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Wood TJ, Davis AT, Earley J, Edyvean S, Findlay U, Lindsay R, Plaistow R, Williams M. IPEM topical report: the first UK survey of cone beam CT dose indices in radiotherapy verification imaging for adult patients. Phys Med Biol 2024; 69:225002. [PMID: 39423854 DOI: 10.1088/1361-6560/ad88d1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Accepted: 10/18/2024] [Indexed: 10/21/2024]
Abstract
Cone beam CT is integral to most modern radiotherapy treatments. The application of daily and repeat CBCT imaging can lead to high imaging doses over a large volume of tissue that extends beyond the treatment site. Hence, it is important to ensure exposures are optimised to keep doses as low as reasonably achievable, whilst ensuring images are suitable for the clinical task. This IPEM topical report presents the results of the first UK survey of dose indices in radiotherapy CBCT. Dose measurements, as defined by the cone beam dose index (CBDIw), were collected along with protocol information for seven treatment sites. Where a range of optimised protocols were available in a centre, a sample of patient data demonstrating the variation in protocol use were requested. Protocol CBDIwvalues were determined from the average dosimetry data for each type of linear accelerator, and median CBDIwand scan length were calculated for each treatment site at each centre. Median CBDIwvalues were compared and summary statistics derived that enable the setting of national dose reference levels (DRLs). A total of 63 UK radiotherapy centres contributed data. The proposed CBDIwDRLs are; prostate 20.6 mGy, gynaecological 20.8 mGy, breast 5.0 mGy, 3D-lung 6.0 mGy, 4D-lung 11.8 mGy, brain 3.5 mGy and head/neck 4.2 mGy. However, large differences between models of imaging system were noted. Where centres had pro-active optimisation strategies in place, such as sized based protocols with selection criteria, dose reductions on the 'average' patient were possible compared with vendor defaults. Optimisation of scan length was noted in some clinical sites, with Elekta users tending to fit different collimators for prostate imaging (relatively short) compared with gynaecological treatments (longest). This contrasts with most Varian users who apply the default scan length in most cases.
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Affiliation(s)
- Tim J Wood
- Institute of Physics and Engineering in Medicine: Radiotherapy and Diagnostic Radiology Special Interest Groups, Doses to patients from x-ray imaging in radiotherapy working party, York, United Kingdom
- Medical Physics Service, Queen's Centre, Castle Hill Hospital, Hull University Teaching Hospitals NHS Trust, Castle Road, Hull HU16 5JQ, United Kingdom
| | - Anne T Davis
- Institute of Physics and Engineering in Medicine: Radiotherapy and Diagnostic Radiology Special Interest Groups, Doses to patients from x-ray imaging in radiotherapy working party, York, United Kingdom
- Medical Physics Department, Portsmouth Hospitals University NHS Trust, Portsmouth PO6 3LY, United Kingdom
| | - James Earley
- Institute of Physics and Engineering in Medicine: Radiotherapy and Diagnostic Radiology Special Interest Groups, Doses to patients from x-ray imaging in radiotherapy working party, York, United Kingdom
- Radiotherapy Physics, Royal Surrey Foundation Trust Hospital NHS Foundation Trust, Guildford, United Kingdom
| | - Sue Edyvean
- Radiation Dosimetry Department, Radiation, Chemicals and Environmental Hazards Directorate, UK Health Security Agency, Chilton, Oxon OX11 0RQ, United Kingdom
| | - Una Findlay
- Medical Exposure Group, Radiation, Chemicals and Environmental Hazards Directorate, UK Health Security Agency, Chilton, Oxon OX11 0RQ, United Kingdom
| | - Rebecca Lindsay
- Institute of Physics and Engineering in Medicine: Radiotherapy and Diagnostic Radiology Special Interest Groups, Doses to patients from x-ray imaging in radiotherapy working party, York, United Kingdom
- Medical Physics Department, Leeds Cancer Centre, Leeds LS9 7TF, United Kingdom
| | - Rosaleen Plaistow
- Institute of Physics and Engineering in Medicine: Radiotherapy and Diagnostic Radiology Special Interest Groups, Doses to patients from x-ray imaging in radiotherapy working party, York, United Kingdom
- Medical Physics Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, United Kingdom
| | - Matthew Williams
- Institute of Physics and Engineering in Medicine: Radiotherapy and Diagnostic Radiology Special Interest Groups, Doses to patients from x-ray imaging in radiotherapy working party, York, United Kingdom
- Radiotherapy Physics, Velindre University NHS Trust, Velindre Road, Whitchurch, Cardiff CF14 2TL, United Kingdom
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Altergot A, Schürmann M, Jungert T, Auerbach H, Nüsken F, Palm J, Rübe C, Rübe CE, Dzierma Y. Imaging doses for different CBCT protocols on the Halcyon 3.0 linear accelerator - TLD measurements in an anthropomorphic phantom. Z Med Phys 2024; 34:580-595. [PMID: 37088675 PMCID: PMC11624401 DOI: 10.1016/j.zemedi.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 02/28/2023] [Accepted: 03/07/2023] [Indexed: 04/25/2023]
Abstract
INTRODUCTION Image guided radiotherapy allows for particularly conformal tumour irradiation through precise patient positioning. Becoming the standard for radiotherapy, this increases imaging doses to the patient. The Halcyon 3.0 linear accelerator (Varian Medical Systems, Palo Alto, CA) requires daily imaging due to its geometry. For this reason, the accelerator is equipped with on-line kV and MV imaging. However, daily CBCT images required for irradiation apply additional radiation, which increases the dose to normal tissue and therefore can affect the patient's secondary cancer risk. In this study, actual organ doses were measured for the kV system, and a comparison of normal tissue doses for all available kV CBCT protocols was presented to demonstrate differences in imaging doses across entities and protocols. In addition, effective dose and secondary cancer risk from imaging are evaluated. MATERIAL AND METHODS Measurements were performed with thermoluminescent dosimeters in an anthropomorphic phantom positioned according to each entity (brain, head and neck, breast, lung, pelvis). CBCT images were obtained, using all available pre-set protocols without further adjustment of the parameters. Measured doses for each position and each protocol were then compared and secondary cancer risk of relevant and specifically radiosensitive organs was calculated. RESULTS It was found that imaging doses for protocols such as Pelvis and Head could be reduced by up to half using the corresponding Fast and Low Dose modes, respectively. On the other hand, larger field sizes or the Large mode yielded higher doses than their initial protocols. Image Gently was found to spare normal tissue best, however it is not suitable for certain entities due to low image quality or insufficient projection data. DISCUSSION By using appropriate kV-CBCT protocols, it is possible to reduce imaging doses to a significant extent and therefore spare healthy tissue. Combined with studies of image quality, the results of this study could lead to adjustments in workflow regarding the choice of protocols used in daily routine. This could prevent unnecessary radiation exposure and reduce secondary cancer risk.
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Affiliation(s)
- Angelika Altergot
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany.
| | - Michaela Schürmann
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Tanja Jungert
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Hendrik Auerbach
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Frank Nüsken
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Jan Palm
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Christian Rübe
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Claudia E Rübe
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Yvonne Dzierma
- Department of Radiotherapy and Radiation Oncology, Saarland University Medical Centre, Homburg/Saar, Germany
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Michail C, Liaparinos P, Kalyvas N, Kandarakis I, Fountos G, Valais I. Radiation Detectors and Sensors in Medical Imaging. SENSORS (BASEL, SWITZERLAND) 2024; 24:6251. [PMID: 39409289 PMCID: PMC11478476 DOI: 10.3390/s24196251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2024] [Revised: 09/23/2024] [Accepted: 09/25/2024] [Indexed: 10/20/2024]
Abstract
Medical imaging instrumentation design and construction is based on radiation sources and radiation detectors/sensors. This review focuses on the detectors and sensors of medical imaging systems. These systems are subdivided into various categories depending on their structure, the type of radiation they capture, how the radiation is measured, how the images are formed, and the medical goals they serve. Related to medical goals, detectors fall into two major areas: (i) anatomical imaging, which mainly concerns the techniques of diagnostic radiology, and (ii) functional-molecular imaging, which mainly concerns nuclear medicine. An important parameter in the evaluation of the detectors is the combination of the quality of the diagnostic result they offer and the burden of the patient with radiation dose. The latter has to be minimized; thus, the input signal (radiation photon flux) must be kept at low levels. For this reason, the detective quantum efficiency (DQE), expressing signal-to-noise ratio transfer through an imaging system, is of primary importance. In diagnostic radiology, image quality is better than in nuclear medicine; however, in most cases, the dose is higher. On the other hand, nuclear medicine focuses on the detection of functional findings and not on the accurate spatial determination of anatomical data. Detectors are integrated into projection or tomographic imaging systems and are based on the use of scintillators with optical sensors, photoconductors, or semiconductors. Analysis and modeling of such systems can be performed employing theoretical models developed in the framework of cascaded linear systems analysis (LCSA), as well as within the signal detection theory (SDT) and information theory.
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Affiliation(s)
| | | | | | - Ioannis Kandarakis
- Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece; (C.M.); (P.L.); (N.K.); (G.F.); (I.V.)
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Haida DM, Mohr P, Won SY, Möhlig T, Holl M, Enk T, Hanschen M, Huber-Wagner S. Hybrid-3D robotic suite in spine and trauma surgery - experiences in 210 patients. J Orthop Surg Res 2024; 19:565. [PMID: 39272126 PMCID: PMC11401291 DOI: 10.1186/s13018-024-05044-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2024] [Accepted: 08/31/2024] [Indexed: 09/15/2024] Open
Abstract
BACKGROUND In modern Hybrid ORs, the synergies of navigation and robotics are assumed to contribute to the optimisation of the treatment in trauma, orthopaedic and spine surgery. Despite promising evidence in the area of navigation and robotics, previous publications have not definitively proven the potential benefits. Therefore, the aim of this retrospective study was to evaluate the potential benefit and clinical outcome of patients treated in a fully equipped 3D-Navigation Hybrid OR. METHODS Prospective data was collected (March 2022- March 2024) after implementation of a fully equipped 3D-Navigation Hybrid OR ("Robotic Suite") in the authors level 1 trauma centre. The OR includes a navigation unit, a cone beam CT (CBCT), a robotic arm and mixed reality glasses. Surgeries with different indications of the spine, the pelvis (pelvic ring and acetabulum) and the extremities were performed. Spinal and non-spinal screws were inserted. The collected data was analysed retrospectively. Pedicle screw accuracy was graded according to the Gertzbein and Robbins (GR) classification. RESULTS A total of n = 210 patients (118 m:92f) were treated in our 3D-Navigation Hybrid OR, with 1171 screws inserted. Among these patients, 23 patients (11.0%) arrived at the hospital via the trauma room with an average Injury Severity Score (ISS) of 25.7. There were 1035 (88.4%) spinal screws inserted at an accuracy rate of 98.7% (CI95%: 98.1-99.4%; 911 GR-A & 111 GR-B screws). The number of non-spinal screws were 136 (11.6%) with an accuracy rate of 99.3% (CI95%: 97.8-100.0%; 135 correctly placed screws). This resulted in an overall accuracy rate of 98.8% (CI95%: 98.2-99.4%). The robotic arm was used in 152 cases (72.4%), minimally invasive surgery (MIS) was performed in 139 cases (66.2%) and wound infection occurred in 4 cases (1,9%). Overall, no revisions were needed. CONCLUSION By extending the scope of application, this study showed that interventions in a fully equipped 3D-Navigation Hybrid OR can be successfully performed not only on the spine, but also on the pelvis and extremities. In trauma, orthopaedics and spinal surgery, navigation and robotics can be used to perform operations with a high degree of precision, increased safety, reduced radiation exposure for the OR-team and a very low complication rate.
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Affiliation(s)
- Dominik M Haida
- Department of Trauma Surgery, Technical University of Munich, Klinikum rechts der Isar, Ismaninger Straße 22, 81675, Munich, Germany
- Department of Trauma Surgery, Diakonie-Klinikum Schwäbisch Hall, Diakoniestraße 10, 74523, Schwäbisch Hall, Germany
| | - Peter Mohr
- Radiation Protection, Diakonie-Klinikum Schwäbisch Hall, Diakoniestraße 10, 74523, Schwäbisch Hall, Germany
| | - Sae-Yeon Won
- Department of Neurosurgery, Rostock University Medical Center, Schillingallee 35, 18057, Rostock, Germany
| | - Thorsten Möhlig
- Department of Trauma Surgery, Diakonie-Klinikum Schwäbisch Hall, Diakoniestraße 10, 74523, Schwäbisch Hall, Germany
| | - Mike Holl
- Department of Trauma Surgery, Diakonie-Klinikum Schwäbisch Hall, Diakoniestraße 10, 74523, Schwäbisch Hall, Germany
| | - Thorsten Enk
- Department of Neurosurgery, Diakonie-Klinikum Schwäbisch Hall, Diakoniestraße 10, 74523, Schwäbisch Hall, Germany
| | - Marc Hanschen
- Department of Trauma Surgery, Technical University of Munich, Klinikum rechts der Isar, Ismaninger Straße 22, 81675, Munich, Germany
| | - Stefan Huber-Wagner
- Department of Trauma Surgery, Technical University of Munich, Klinikum rechts der Isar, Ismaninger Straße 22, 81675, Munich, Germany.
- Department of Trauma Surgery, Diakonie-Klinikum Schwäbisch Hall, Diakoniestraße 10, 74523, Schwäbisch Hall, Germany.
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Abuhaimed A, Mujammami H, AlEnazi K, Abanomy A, Alashban Y, Martin CJ. Estimation of organ and effective doses of CBCT scans of radiotherapy using size-specific field of view (FOV): a Monte Carlo study. Phys Eng Sci Med 2024; 47:895-906. [PMID: 38536632 DOI: 10.1007/s13246-024-01413-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 03/04/2024] [Indexed: 09/18/2024]
Abstract
The kV cone beam computed tomography (CBCT) is one of the most common imaging modalities used for image-guided radiation therapy (IGRT) procedures. Additional doses are delivered to patients, thus assessment and optimization of the imaging doses should be taken into consideration. This study aimed to investigate the influence of using fixed and patient-specific FOVs on the patient dose. Monte Carlo simulations were performed to simulate kV beams of the imaging system integrated into Truebeam linear accelerator using BEAMnrc code. Organ and size-specific effective doses resulting from chest and pelvis scanning protocols were estimated with DOSXYZnrc code using a phantom library developed by the National Cancer Institute (NCI) of the US. The library contains 193 (100 male and 93 female) mesh-type computational human adult phantoms, and it covers a large ratio of patient sizes with heights and weights ranging from 150 to 190 cm and 40 to 125 kg. The imaging doses were assessed using variable FOV of three sizes, small (S), medium (M), and large (L) for each scan region. The results show that the FOV and the patient size played a major role in the scan dose. The average percentage differences (PDs) for doses of organs that were fully inside the different FOVs were relatively low, all within 11% for both protocols. However, doses to organs that were scanned partially or near the FOVs were affected significantly. For the chest protocol, the inclusion of the thyroid in the scan field could give a dose of 1-7 mGy/100 mAs to the thyroid, compared to 0.4-1 mGy/100 mAs when it was excluded. Similarly, on average, testes doses could be 6 mGy/100 mAs for the male pelvis protocol compared to 3 mGy/100 mAs when it did not lie in the field irradiated. These dose differences resulted in an average increase of up to 27% in the size-specific effective dose of the protocols. Since changing the field size is possible for CBCT scans, the results suggest that patient-specific scanning protocols could be applied for each scan area in a manner similar to that used for CT scans. Adjustment of the FOV size should be subject to the clinical needs, and assist in improving the treatment accuracy. The patient's height and weight might be considered as the main factors upon which, the selection of the appropriate patient-specific protocol is based. This approach should optimize the imaging doses used for IGRT procedures by minimizing doses of a large ratio of patients.
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Affiliation(s)
- Abdullah Abuhaimed
- King Abdulaziz City for Science and Technology (KACST), P.O Box 6086, 11442, Riyadh, Saudi Arabia.
| | - Huda Mujammami
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, 4545, Riyadh, Saudi Arabia
| | - Khaled AlEnazi
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, 4545, Riyadh, Saudi Arabia
| | - Ahmed Abanomy
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, 4545, Riyadh, Saudi Arabia
| | - Yazeed Alashban
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, P.O. Box 145111, 4545, Riyadh, Saudi Arabia
| | - Colin J Martin
- Department of Clinical Physics and Bio-Engineering, Gartnavel Royal Hospital, University of Glasgow, Glasgow, G12 8QQ, UK
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Gáldi Á, Farkas G, Gazdag-Hegyesi S, Koszta E, Ágoston P, Pesznyák C, Major T, Takácsi-Nagy Z, Polgár C, Jurányi Z. Combined biological effects of CBCT and therapeutic X-ray dose on chromosomal aberrations of lymphocytes. Radiat Oncol 2024; 19:109. [PMID: 39143640 PMCID: PMC11325805 DOI: 10.1186/s13014-024-02504-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 08/05/2024] [Indexed: 08/16/2024] Open
Abstract
BACKGROUND AND PURPOSE Cone beam computed tomography (CBCT) is routinely used in radiotherapy to localize target volume. The aim of our study was to determine the biological effects of CBCT dose compared to subsequent therapeutic dose by using in vitro chromosome dosimetry. MATERIALS AND METHODS Peripheral blood samples from five healthy volunteers were irradiated in two phantoms (water filled in-house made cylindrical, and Pure Image CTDI phantoms) with 6 MV FFF X-ray photons, the dose rate was 800 MU/min and the absorbed doses ranged from 0.5 to 8 Gy. Irradiation was performed with a 6 MV linear accelerator (LINAC) to generate a dose-response calibration curve. In the first part of the investigation, 1-5 CBCT imaging was used, in the second, only 2 Gy doses were delivered with a LINAC, and then, in the third part, a combination of CBCT and 2 Gy irradiation was performed mimicking online adapted radiotherapy treatment. Metaphases were prepared from lymphocyte cultures, using standard cytogenetic techniques, and chromosomal aberrations were evaluated. Estimate doses were calculated from chromosome aberrations using dose-response curves. RESULTS Samples exposed to X-ray from CBCT imaging prior to treatment exhibited higher chromosomal aberrations and Estimate dose than the 2 Gy therapeutic (real) dose, and the magnitude of the increase depended on the number of CBCTs: 1-5 CBCT corresponded to 0.04-0.92 Gy, 1 CBCT + 2 Gy to 2.32 Gy, and 5 CBCTs + 2 Gy to 3.5 Gy. CONCLUSION The estimated dose based on chromosomal aberrations is 24.8% higher than the physical dose, for the combination of 3 CBCTs and the therapeutic 2 Gy dose, which should be taken into account when calculating the total therapeutic dose that could increase the risk of a second cancer. The clinical implications of the combined radiation effect may require further investigation.
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Affiliation(s)
- Ádám Gáldi
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary.
- Doctoral College, Semmelweis University, Budapest, Hungary.
| | - Gyöngyi Farkas
- Department of Radiobiology and Diagnostic Onco-Cytogenetics, Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
| | - Szilvia Gazdag-Hegyesi
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Doctoral School of Physical Sciences, University of Technology and Economics, Budapest, Hungary
| | - Enikő Koszta
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Doctoral School of Physical Sciences, University of Technology and Economics, Budapest, Hungary
| | - Péter Ágoston
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Department of Oncology, National Institute of Oncology, Semmelweis University, Ráth György U.7-9, Budapest, 1122, Hungary
| | - Csilla Pesznyák
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Institute of Nuclear Techniques, University of Technology and Economics, Budapest, Hungary
| | - Tibor Major
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Department of Oncology, National Institute of Oncology, Semmelweis University, Ráth György U.7-9, Budapest, 1122, Hungary
| | - Zoltán Takácsi-Nagy
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Department of Oncology, National Institute of Oncology, Semmelweis University, Ráth György U.7-9, Budapest, 1122, Hungary
| | - Csaba Polgár
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Department of Oncology, National Institute of Oncology, Semmelweis University, Ráth György U.7-9, Budapest, 1122, Hungary
| | - Zsolt Jurányi
- Centre of Radiotherapy, National Institute of Oncology, Ráth György U. 7-9, Budapest, 1122, Hungary
- Department of Oncology, National Institute of Oncology, Semmelweis University, Ráth György U.7-9, Budapest, 1122, Hungary
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Siiskonen T, Alenius S, Seppälä T, Tikkanen J, Nadhum M, Ojala J. Cone beam CT doses in radiotherapy patient positioning in Finland-prostate treatments. RADIATION PROTECTION DOSIMETRY 2024; 200:842-847. [PMID: 38828501 DOI: 10.1093/rpd/ncae133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/22/2024] [Accepted: 05/17/2024] [Indexed: 06/05/2024]
Abstract
Imaging parameters, frequencies and resulting patient organ doses in treatments of prostate cancer were assessed in Finnish radiotherapy centres. Based on a questionnaire to the clinics, Monte Carlo method was used to estimate organ doses in International Commission on Radiological Protection standard phantom for prostate, bladder, rectum and femoral head. The results show that doses from cone beam computed tomography imaging have reduced compared to earlier studies and are between 3.6 and 34.5 mGy per image for the above-mentioned organs and for normal sized patients. There still is room for further optimization of the patient exposure, as many centres use the default imaging parameters, and the length of the imaged region may not be optimal for the purpose.
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Affiliation(s)
- Teemu Siiskonen
- Department of Physics, University of Helsinki, P.O. Box 64 (Gustaf Hällströmin katu 2), FI-00014 Helsinki, Finland
- STUK-Radiation and Nuclear Safety Authority, Measurements and Environmental Surveillance, Jokiniemenkuja 1, FI-01370 Vantaa, Finland
| | - Saara Alenius
- Department of Physics, University of Helsinki, P.O. Box 64 (Gustaf Hällströmin katu 2), FI-00014 Helsinki, Finland
| | - Tiina Seppälä
- Comprehensive Cancer Center, Helsinki University Hospital and University of Helsinki, PL180, 00290 Helsinki, Finland
| | - Joonas Tikkanen
- STUK-Radiation and Nuclear Safety Authority, Measurements and Environmental Surveillance, Jokiniemenkuja 1, FI-01370 Vantaa, Finland
| | - Miia Nadhum
- Department of Medical Physics, Tampere University Hospital, FI-33521 Tampere, Finland
- Faculty of Medicine and Health Technology, Tampere University, FI-33720 Tampere, Finland
| | - Jarkko Ojala
- Department of Medical Physics, Tampere University Hospital, FI-33521 Tampere, Finland
- Faculty of Medicine and Health Technology, Tampere University, FI-33720 Tampere, Finland
- Department of Oncology, Tampere University Hospital, FI-33521 Tampere, Finland
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Frencken AL, Richtsmeier D, Leonard RL, Williams AG, Johnson CE, Johnson JA, Blasiak B, Orlef A, Skorupa A, Sokół M, Tomanek B, Beckham W, Bazalova-Carter M, van Veggel FCJM. X-ray-Sensitive Doped CaF 2-Based MRI Contrast Agents for Local Radiation Dose Measurement. ACS APPLIED MATERIALS & INTERFACES 2024; 16:13453-13465. [PMID: 38445594 DOI: 10.1021/acsami.3c16336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Ionizing radiation has become widely used in medicine, with application in diagnostic techniques, such as computed tomography (CT) and radiation therapy (RT), where X-rays are used to diagnose and treat tumors. The X-rays used in CT and, in particular, in RT can have harmful side effects; hence, an accurate determination of the delivered radiation dose is of utmost importance to minimize any damage to healthy tissues. For this, medical specialists mostly rely on theoretical predictions of the delivered dose or external measurements of the dose. To extend the practical use of ionizing radiation-based medical techniques, such as magnetic resonance imaging (MRI)-guided RT, a more precise measurement of the internal radiation dose internally is required. In this work, a novel approach is presented to measure dose in liquids for potential future in vivo applications. The strategy relies on MRI contrast agents (CAs) that provide a dose-sensitive signal. The demonstrated materials are (citrate-capped) CaF2 nanoparticles (NPs) doped with Eu3+ or Fe2+/Fe3+ ions. Free electrons generated by ionizing radiation allow the reduction of Eu3+, which produces a very small contrast in MRI, to Eu2+, which induces a strong contrast. Oxidative species generated by high-energy X-rays can be measured indirectly using Fe2+ because it oxidizes to Fe3+, increasing the contrast in MRI. Notably, in the results, a strong increase in the proton relaxation rates is observed for the Eu3+-doped NPs at 40 kV. At 6 MV, a significant increase in proton relaxation rates is observed using CaF2 NPs doped with Fe2+/Fe3+ after irradiation. The presented concept shows great promise for use in the clinic to measure in vivo local ionizing radiation dose, as these CAs can be intravenously injected in a saline solution.
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Affiliation(s)
- Adriaan L Frencken
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Devon Richtsmeier
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - R Lee Leonard
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Aleia G Williams
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Charles E Johnson
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Jacqueline A Johnson
- Aerospace and Biomedical Engineering, The University of Tennessee Space Institute Tullahoma, Tullahoma, Tennessee 37388-9700, United States
| | - Barbara Blasiak
- Experimental Imaging Centre, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow 31-342, Poland
| | - Andrzej Orlef
- Department of Medical Physics, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-102 Gliwice, Poland
| | - Agnieszka Skorupa
- Department of Medical Physics, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-102 Gliwice, Poland
| | - Maria Sokół
- Department of Medical Physics, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-102 Gliwice, Poland
| | - Boguslaw Tomanek
- Experimental Imaging Centre, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow 31-342, Poland
- Oncology Department, University of Alberta, 8303-112 Street NW, Edmonton, Alberta T6G 2T4, Canada
| | - Wayne Beckham
- BC Cancer, Royal Jubilee Hospital, Victoria, British Columbia V8R 6 V5, Canada
| | - Magdalena Bazalova-Carter
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Frank C J M van Veggel
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Centre for Advanced Materials & Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
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9
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Moglioni M, Carra P, Arezzini S, Belcari N, Bersani D, Berti A, Bisogni MG, Calderisi M, Ceppa I, Cerello P, Ciocca M, Ferrero V, Fiorina E, Kraan AC, Mazzoni E, Morrocchi M, Pennazio F, Retico A, Rosso V, Sbolgi F, Vitolo V, Sportelli G. Synthetic CT imaging for PET monitoring in proton therapy: a simulation study. Phys Med Biol 2024; 69:065011. [PMID: 38373343 DOI: 10.1088/1361-6560/ad2a99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 02/19/2024] [Indexed: 02/21/2024]
Abstract
Objective.This study addresses a fundamental limitation of in-beam positron emission tomography (IB-PET) in proton therapy: the lack of direct anatomical representation in the images it produces. We aim to overcome this shortcoming by pioneering the application of deep learning techniques to create synthetic control CT images (sCT) from combining IB-PET and planning CT scan data.Approach.We conducted simulations involving six patients who underwent irradiation with proton beams. Leveraging the architecture of a visual transformer (ViT) neural network, we developed a model to generate sCT images of these patients using the planning CT scans and the inter-fractional simulated PET activity maps during irradiation. To evaluate the model's performance, a comparison was conducted between the sCT images produced by the ViT model and the authentic control CT images-serving as the benchmark.Main results.The structural similarity index was computed at a mean value across all patients of 0.91, while the mean absolute error measured 22 Hounsfield Units (HU). Root mean squared error and peak signal-to-noise ratio values were 56 HU and 30 dB, respectively. The Dice similarity coefficient exhibited a value of 0.98. These values are comparable to or exceed those found in the literature. More than 70% of the synthetic morphological changes were found to be geometrically compatible with the ones reported in the real control CT scan.Significance.Our study presents an innovative approach to surface the hidden anatomical information of IB-PET in proton therapy. Our ViT-based model successfully generates sCT images from inter-fractional PET data and planning CT scans. Our model's performance stands on par with existing models relying on input from cone beam CT or magnetic resonance imaging, which contain more anatomical information than activity maps.
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Affiliation(s)
- Martina Moglioni
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | - Pietro Carra
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | - Silvia Arezzini
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | - Nicola Belcari
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | - Davide Bersani
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
| | - Andrea Berti
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | - Maria Giuseppina Bisogni
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | | | | | - Piergiorgio Cerello
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy
| | - Mario Ciocca
- Centro Nazionale di Adroterapia Oncologica, I-27100 Pavia, Italy
| | - Veronica Ferrero
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy
| | - Elisa Fiorina
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy
| | | | - Enrico Mazzoni
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
| | - Matteo Morrocchi
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | - Francesco Pennazio
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino, Italy
| | - Alessandra Retico
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
| | - Valeria Rosso
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
| | | | - Viviana Vitolo
- Centro Nazionale di Adroterapia Oncologica, I-27100 Pavia, Italy
| | - Giancarlo Sportelli
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
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10
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Tsironi F, Myronakis M, Stratakis J, Sotiropoulou V, Damilakis J. Organ dose prediction for patients undergoing radiotherapy CBCT chest examinations using artificial intelligence. Phys Med 2024; 119:103305. [PMID: 38320358 DOI: 10.1016/j.ejmp.2024.103305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/13/2024] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
PURPOSE To propose an artificial intelligence (AI)-based method for personalized and real-time dosimetry for chest CBCT acquisitions. METHODS CT images from 113 patients who underwent radiotherapy treatment were collected for simulating thorax examinations using cone-beam computed tomography (CBCT) with the Monte Carlo technique. These simulations yielded organ dose data, used to train and validate specific AI algorithms. The efficacy of these AI algorithms was evaluated by comparing dose predictions with the actual doses derived from Monte Carlo simulations, which are the ground truth, utilizing Bland-Altman plots for this comparative analysis. RESULTS The absolute mean discrepancies between the predicted doses and the ground truth are (0.9 ± 1.3)% for bones, (1.2 ± 1.2)% for the esophagus, (0.5 ± 1.3)% for the breast, (2.5 ± 1.4)% for the heart, (2.4 ± 2.1)% for lungs, (0.8 ± 0.6)% for the skin, and (1.7 ± 0.7)% for integral. Meanwhile, the maximum discrepancies between the predicted doses and the ground truth are (14.4 ± 1.3)% for bones, (12.9 ± 1.2)% for the esophagus, (9.4 ± 1.3)% for the breast, (14.6 ± 1.4)% for the heart, (21.2 ± 2.1)% for lungs, (10.0 ± 0.6)% for the skin, and (10.5 ± 0.7)% for integral. CONCLUSIONS AI models that can make real-time predictions of the organ doses for patients undergoing CBCT thorax examinations as part of radiotherapy pre-treatment positioning were developed. The results of this study clearly show that the doses predicted by analyzed AI models are in close agreement with those calculated using Monte Carlo simulations.
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Affiliation(s)
- Fereniki Tsironi
- Department of Medical Physics, University Hospital of Crete, Iraklion, Greece
| | - Marios Myronakis
- Department of Medical Physics, School of Medicine, University of Crete, Iraklion, Greece
| | - John Stratakis
- Department of Medical Physics, University Hospital of Crete, Iraklion, Greece; Department of Medical Physics, School of Medicine, University of Crete, Iraklion, Greece
| | | | - John Damilakis
- Department of Medical Physics, University Hospital of Crete, Iraklion, Greece; Department of Medical Physics, School of Medicine, University of Crete, Iraklion, Greece.
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11
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Becksfort J, Uh J, Saunders A, Byrd JA, Worrall HM, Marker M, Melendez-Suchi C, Li Y, Chang J, Raghavan K, Merchant TE, Hua CH. Setup Uncertainty of Pediatric Brain Tumor Patients Receiving Proton Therapy: A Prospective Study. Cancers (Basel) 2023; 15:5486. [PMID: 38001746 PMCID: PMC10670653 DOI: 10.3390/cancers15225486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/11/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
This study quantifies setup uncertainty in brain tumor patients who received image-guided proton therapy. Patients analyzed include 165 children, adolescents, and young adults (median age at radiotherapy: 9 years (range: 10 months to 24 years); 80 anesthetized and 85 awake) enrolled in a single-institution prospective study from 2020 to 2023. Cone-beam computed tomography (CBCT) was performed daily to calculate and correct manual setup errors, once per course after setup correction to measure residual errors, and weekly after treatments to assess intrafractional motion. Orthogonal radiographs were acquired consecutively with CBCT for paired comparisons of 40 patients. Translational and rotational errors were converted from 6 degrees of freedom to a scalar by a statistical approach that considers the distance from the target to the isocenter. The 95th percentile of setup uncertainty was reduced by daily CBCT from 10 mm (manual positioning) to 1-1.5 mm (after correction) and increased to 2 mm by the end of fractional treatment. A larger variation existed between the roll corrections reported by radiographs vs. CBCT than for pitch and yaw, while there was no statistically significant difference in translational variation. A quantile mixed regression model showed that the 95th percentile of intrafractional motion was 0.40 mm lower for anesthetized patients (p=0.0016). Considering additional uncertainty in radiation-imaging isocentricity, the commonly used total plan robustness of 3 mm against positional uncertainty would be appropriate for our study cohort.
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Affiliation(s)
- Jared Becksfort
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Jinsoo Uh
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Andrew Saunders
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Julia A. Byrd
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Hannah M. Worrall
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Matt Marker
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Christian Melendez-Suchi
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Yimei Li
- Department of Biostatistics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Jenghwa Chang
- Department of Radiation Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY 11549, USA
| | - Kavitha Raghavan
- Department of Pediatric Medicine, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA;
| | - Thomas E. Merchant
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
| | - Chia-ho Hua
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (J.U.); (J.A.B.); (H.M.W.); (T.E.M.); (C.-h.H.)
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12
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Velonis M, Papanastasiou E, Hatziioannou K, Siountas A, Kamperis E, Papavasileiou P, Koukourakis MI, Seimenis I. Dose optimization of 2D X-ray image acquisition protocols in image-guided radiotherapy. Phys Med 2023; 115:103161. [PMID: 37847953 DOI: 10.1016/j.ejmp.2023.103161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 09/06/2023] [Accepted: 10/06/2023] [Indexed: 10/19/2023] Open
Abstract
PURPOSE In contemporary radiotherapy, patient positioning accuracy relies on kV imaging. This study aims at optimizing planar kV image acquisition protocols regarding patient dose without degrading image quality. MATERIALS AND METHODS An image quality test-object was placed in-between PMMA plates, suitably arranged to model head or pelvis. Constructed phantoms were imaged using default protocols, the resultant image quality was assessed and the corresponding radiation dose was measured. The process was repeated using numerous kV/mAs combinations to identify those acquisition settings providing images at lower dose than the default protocols but without deterioration in image quality. Default and dose-optimized protocols were then tested on an anthropomorphic phantom and on 51 patients during two successive treatment sessions. Image quality was independently assessed by two readers. Organ and effective doses were estimated using a Monte Carlo simulation software. RESULTS Low-contrast detectability exhibited a stronger dependence on kV/mAs settings, compared to high-contrast resolution. Dose-optimized protocols resulted in significant dose reductions (anteroposterior-head 48.0 %, lateral-head 30.0 %, anteroposterior-pelvis 28.4 %, lateral-pelvis 27.0 %) compared to the default ones, without compromising image quality. Optimized protocols decreased effective doses by 54 % and 29.6 % in head and pelvic acquisitions, respectively. Regarding image quality, anthropomorphic and patient images acquired using the dose-optimized protocols were subjectively evaluated equivalent to those obtained with the corresponding default settings, indicating that the proposed protocols may be routinely used. CONCLUSIONS Given the potentially large number of radiotherapy fractions and the pertinent image acquisitions, dose-optimized protocols could significantly reduce patient dose associated with planar imaging without compromising positioning accuracy.
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Affiliation(s)
- Marios Velonis
- Department of Medicine, Faculty of Health Sciences, Democritus University of Thrace, Greece; Department of Medical Physics, Papageorgiou General Hospital, Thessaloniki, Greece.
| | - Emmanouil Papanastasiou
- Medical Physics & Digital Innovation Laboratory, Medical School, Aristotle University of Thessaloniki, Greece
| | | | - Anastasios Siountas
- Medical Physics & Digital Innovation Laboratory, Medical School, Aristotle University of Thessaloniki, Greece
| | - Efstathios Kamperis
- Department of Radiotherapy, Papageorgiou General Hospital, Thessaloniki, Greece
| | - Periklis Papavasileiou
- Department of Biomedical Sciences, School of Health Sciences, University of West Attica, Greece
| | - Michael I Koukourakis
- Department of Medicine, Faculty of Health Sciences, Democritus University of Thrace, Greece
| | - Ioannis Seimenis
- Medical Physics Laboratory, School of Medicine, National and Kapodistrian University of Athens, Greece
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13
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Hu D, Zhang Y, Li W, Zhang W, Reddy K, Ding Q, Zhang X, Chen Y, Gao H. SEA-Net: Structure-Enhanced Attention Network for Limited-Angle CBCT Reconstruction of Clinical Projection Data. IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2023; 72:4507613. [PMID: 38957474 PMCID: PMC11218899 DOI: 10.1109/tim.2023.3318712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
This work aims to improve limited-angle (LA) cone beam computed tomography (CBCT) by developing deep learning (DL) methods for real clinical CBCT projection data, which is the first feasibility study of clinical-projection-data-based LA-CBCT, to the best of our knowledge. In radiation therapy (RT), CBCT is routinely used as the on-board imaging modality for patient setup. Compared to diagnostic CT, CBCT has a long acquisition time, e.g., 60 seconds for a full 360° rotation, which is subject to the motion artifact. Therefore, the LA-CBCT, if achievable, is of the great interest for the purpose of RT, for its proportionally reduced scanning time in addition to the radiation dose. However, LA-CBCT suffers from severe wedge artifacts and image distortions. Targeting at real clinical projection data, we have explored various DL methods such as image/data/hybrid-domain methods and finally developed a so-called Structure-Enhanced Attention Network (SEA-Net) method that has the best image quality from clinical projection data among the DL methods we have implemented. Specifically, the proposed SEA-Net employs a specialized structure enhancement sub-network to promote texture preservation. Based on the observation that the distribution of wedge artifacts in reconstruction images is non-uniform, the spatial attention module is utilized to emphasize the relevant regions while ignores the irrelevant ones, which leads to more accurate texture restoration.
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Affiliation(s)
- Dianlin Hu
- Department of Radiation Oncology, University of Kansas Medical Center, KS 66160, USA
- Jiangsu Provincial Joint International Research Laboratory of Medical Information Processing, the Laboratory of Image Science and Technology, the School of Computer Science and Engineering, and the Key Laboratory of New Generation Artificial Intelligence Technology and Its Interdisciplinary Applications (Southeast University), Ministry of Education, Nanjing 210096, China
| | - Yikun Zhang
- Department of Radiation Oncology, University of Kansas Medical Center, KS 66160, USA
- Jiangsu Provincial Joint International Research Laboratory of Medical Information Processing, the Laboratory of Image Science and Technology, the School of Computer Science and Engineering, and the Key Laboratory of New Generation Artificial Intelligence Technology and Its Interdisciplinary Applications (Southeast University), Ministry of Education, Nanjing 210096, China
| | - Wangyao Li
- Department of Radiation Oncology, University of Kansas Medical Center, KS 66160, USA
| | - Weijie Zhang
- Department of Radiation Oncology, University of Kansas Medical Center, KS 66160, USA
| | - Krishna Reddy
- Department of Radiation Oncology, University of Kansas Medical Center, KS 66160, USA
| | - Qiaoqiao Ding
- Institute of Natural Sciences & School of Mathematical Sciences & MOE-LSC & SJTU-GenSci Joint Lab, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaoqun Zhang
- Institute of Natural Sciences & School of Mathematical Sciences & MOE-LSC & SJTU-GenSci Joint Lab, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yang Chen
- Jiangsu Provincial Joint International Research Laboratory of Medical Information Processing, the Laboratory of Image Science and Technology, the School of Computer Science and Engineering, and the Key Laboratory of New Generation Artificial Intelligence Technology and Its Interdisciplinary Applications (Southeast University), Ministry of Education, Nanjing 210096, China
| | - Hao Gao
- Department of Radiation Oncology, University of Kansas Medical Center, KS 66160, USA
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14
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Milana M, Jelena M, Borislava P. Quality assurance of six cylindrical and two parallel plate chambers by radioactive check device: Influence of chamber age to its performance. Phys Med 2023; 112:102635. [PMID: 37480711 DOI: 10.1016/j.ejmp.2023.102635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 05/02/2023] [Accepted: 07/04/2023] [Indexed: 07/24/2023] Open
Abstract
PURPOSE To evaluate the performances of eight ionization chambers, (two types) manufactured in a time span of 14 years, with radioactive source devices and photon beams. METHODS The measurements were performed with six Farmer and two parallel plate ionization chambers with appropriate radioactive check devices and accompanying inserts. Some tests were performed with photon beams at linear accelerator. Physical visibility check, stability, linearity of response, directional dependence, determination of leakage current, ion recombination and polarity effect and influence of background radiation tests were conducted and analyzed. RESULTS The performance of all Farmer ionization chambers was in agreement to IEC standard as well as for parallel plate type chambers. Long-term stability of older planparallel chamber was somewhat worse than expected. CONCLUSION Radioactive check devices have proven to be easy to use in clinical environment. According to results of this work Farmer type ionization chambers showed good quality regardless of the time of production, which make them long-term suitable for clinical dosimetry in radiotherapy. Also, for parallel plate type of ionization chambers the results showed fine agreement with the IEC standard, except long-term stability for older chamber, which needs further investigation.
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Affiliation(s)
- Marjanovic Milana
- Radiotherapy Department, Oncology Institute of Vojvodina, Put dr Goldmana 4, 21204 Sremska Kamenica, Serbia; Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia.
| | - Moravčević Jelena
- Radiotherapy Department, Oncology Institute of Vojvodina, Put dr Goldmana 4, 21204 Sremska Kamenica, Serbia.
| | - Petrović Borislava
- Radiotherapy Department, Oncology Institute of Vojvodina, Put dr Goldmana 4, 21204 Sremska Kamenica, Serbia; Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia.
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15
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Harris TC, Jacobson M, Myronakis M, Lehmann M, Huber P, Morf D, Ozoemelam I, Hu YH, Ferguson D, Fueglistaller R, Corral Arroyo P, Berbeco RI. Impact of a novel multilayer imager on metal artifacts in MV-CBCT. Phys Med Biol 2023; 68:10.1088/1361-6560/ace09a. [PMID: 37343590 PMCID: PMC10382207 DOI: 10.1088/1361-6560/ace09a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/21/2023] [Indexed: 06/23/2023]
Abstract
Objective. Megavoltage cone-beam computed tomography (MV-CBCT) imaging offers several advantages including reduced metal artifacts and accurate electron density mapping for adaptive or emergent situations. However, MV-CBCT imaging is limited by the poor efficiency of current detectors. Here we examine a new MV imager and compare CBCT reconstructions under clinically relevant scenarios.Approach. A multilayer imager (MLI), consisting of four vertically stacked standard flat-panel imagers, was mounted to a clinical linear accelerator. A custom anthropomorphic pelvis phantom with replaceable femoral heads was imaged using MV-CBCT and kilovoltage CBCT (kV-CBCT). Bone, aluminum, and titanium were used as femoral head inserts. 8 MU 2.5 MV scans were acquired for all four layers and (as reference) the top layer. Prostate and bladder were contoured on a reference CT and transferred to the other scans after rigid registration, from which the structural similarity index measure (SSIM) was calculated. Prostate and bladder were also contoured on CBCT scans without guidance, and Dice coefficients were compared to CT contours.Main results. kV-CBCT demonstrated the highest SSIMs with bone inserts (prostate: 0.86, bladder: 0.94) and lowest with titanium inserts (0.32, 0.37). Four-layer MV-CBCT SSIMs were preserved with bone (0.75, 0.80) as compared to titanium (0.67, 0.74), outperforming kV-CBCT when metal is present. One-layer MV-CBCT consistently underperformed four-layer results across all phantom configurations. Unilateral titanium inserts and bilateral aluminum insert results fell between the bone and bilateral titanium results. Dice coefficients trended similarly, with four-layer MV-CBCT reducing metal artifact impact relative to KV-CBCT to provide better soft-tissue identification.Significance. MV-CBCT with a four-layer MLI showed improvement over single-layer MV scans, approaching kV-CBCT quality for soft-tissue contrast. In the presence of artifact-producing metal implants, four-layer MV-CBCT scans outperformed kV-CBCT by eliminating artifacts and single-layer MV-CBCT by reducing noise. MV-CBCT with a novel multi-layer imager may be a valuable alternative to kV-CBCT, particularly in the presence of metal.
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Affiliation(s)
- T C Harris
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
| | - M Jacobson
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
| | - M Myronakis
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
| | - M Lehmann
- Varian Medical Systems, Baden-Dattwil, Switzerland
| | - P Huber
- Varian Medical Systems, Baden-Dattwil, Switzerland
| | - D Morf
- Varian Medical Systems, Baden-Dattwil, Switzerland
| | - I Ozoemelam
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
| | - Y H Hu
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
| | - D Ferguson
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
| | | | | | - R I Berbeco
- Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA, United States of America
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16
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Lavrova E, Garrett MD, Wang YF, Chin C, Elliston C, Savacool M, Price M, Kachnic LA, Horowitz DP. Adaptive Radiation Therapy: A Review of CT-based Techniques. Radiol Imaging Cancer 2023; 5:e230011. [PMID: 37449917 PMCID: PMC10413297 DOI: 10.1148/rycan.230011] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/18/2023] [Accepted: 05/10/2023] [Indexed: 07/18/2023]
Abstract
Adaptive radiation therapy is a feedback process by which imaging information acquired over the course of treatment, such as changes in patient anatomy, can be used to reoptimize the treatment plan, with the end goal of improving target coverage and reducing treatment toxicity. This review describes different types of adaptive radiation therapy and their clinical implementation with a focus on CT-guided online adaptive radiation therapy. Depending on local anatomic changes and clinical context, different anatomic sites and/or disease stages and presentations benefit from different adaptation strategies. Online adaptive radiation therapy, where images acquired in-room before each fraction are used to adjust the treatment plan while the patient remains on the treatment table, has emerged to address unpredictable anatomic changes between treatment fractions. Online treatment adaptation places unique pressures on the radiation therapy workflow, requiring high-quality daily imaging and rapid recontouring, replanning, plan review, and quality assurance. Generating a new plan with every fraction is resource intensive and time sensitive, emphasizing the need for workflow efficiency and clinical resource allocation. Cone-beam CT is widely used for image-guided radiation therapy, so implementing cone-beam CT-guided online adaptive radiation therapy can be easily integrated into the radiation therapy workflow and potentially allow for rapid imaging and replanning. The major challenge of this approach is the reduced image quality due to poor resolution, scatter, and artifacts. Keywords: Adaptive Radiation Therapy, Cone-Beam CT, Organs at Risk, Oncology © RSNA, 2023.
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Affiliation(s)
- Elizaveta Lavrova
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Matthew D. Garrett
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Yi-Fang Wang
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Christine Chin
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Carl Elliston
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Michelle Savacool
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Michael Price
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - Lisa A. Kachnic
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
| | - David P. Horowitz
- From the Department of Radiation Oncology, Columbia University Irving
Medical Center, 622 W 168th St, New York, NY 10032 (E.L., M.D.G., Y.F.W., C.C.,
C.E., M.S., M.P., L.A.K., D.P.H.); and Herbert Irving Comprehensive Cancer
Center, New York, NY (C.C., L.A.K., D.P.H.)
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17
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Szmul A, Taylor S, Lim P, Cantwell J, Moreira I, Zhang Y, D’Souza D, Moinuddin S, Gaze MN, Gains J, Veiga C. Deep learning based synthetic CT from cone beam CT generation for abdominal paediatric radiotherapy. Phys Med Biol 2023; 68:105006. [PMID: 36996837 PMCID: PMC10160738 DOI: 10.1088/1361-6560/acc921] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 03/13/2023] [Accepted: 03/30/2023] [Indexed: 04/01/2023]
Abstract
Objective. Adaptive radiotherapy workflows require images with the quality of computed tomography (CT) for re-calculation and re-optimisation of radiation doses. In this work we aim to improve the quality of on-board cone beam CT (CBCT) images for dose calculation using deep learning.Approach. We propose a novel framework for CBCT-to-CT synthesis using cycle-consistent Generative Adversarial Networks (cycleGANs). The framework was tailored for paediatric abdominal patients, a challenging application due to the inter-fractional variability in bowel filling and small patient numbers. We introduced to the networks the concept of global residuals only learning and modified the cycleGAN loss function to explicitly promote structural consistency between source and synthetic images. Finally, to compensate for the anatomical variability and address the difficulties in collecting large datasets in the paediatric population, we applied a smart 2D slice selection based on the common field-of-view (abdomen) to our imaging dataset. This acted as a weakly paired data approach that allowed us to take advantage of scans from patients treated for a variety of malignancies (thoracic-abdominal-pelvic) for training purposes. We first optimised the proposed framework and benchmarked its performance on a development dataset. Later, a comprehensive quantitative evaluation was performed on an unseen dataset, which included calculating global image similarity metrics, segmentation-based measures and proton therapy-specific metrics.Main results. We found improved performance for our proposed method, compared to a baseline cycleGAN implementation, on image-similarity metrics such as Mean Absolute Error calculated for a matched virtual CT (55.0 ± 16.6 HU proposed versus 58.9 ± 16.8 HU baseline). There was also a higher level of structural agreement for gastrointestinal gas between source and synthetic images measured using the dice similarity coefficient (0.872 ± 0.053 proposed versus 0.846 ± 0.052 baseline). Differences found in water-equivalent thickness metrics were also smaller for our method (3.3 ± 2.4% proposed versus 3.7 ± 2.8% baseline).Significance. Our findings indicate that our innovations to the cycleGAN framework improved the quality and structure consistency of the synthetic CTs generated.
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Affiliation(s)
- Adam Szmul
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
| | - Sabrina Taylor
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Pei Lim
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Jessica Cantwell
- Radiotherapy, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Isabel Moreira
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Ying Zhang
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Derek D’Souza
- Radiotherapy Physics Services, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Syed Moinuddin
- Radiotherapy, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Mark N. Gaze
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Jennifer Gains
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Catarina Veiga
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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18
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Seller Oria C, Free J, Marmitt GG, Knäusl B, Brandenburg S, Knopf AC, Meijers A, Langendijk JA, Both S. Technical note: Flat panel proton radiography with a patient specific imaging field for accurate WEPL assessment. Med Phys 2023; 50:1756-1765. [PMID: 36629844 DOI: 10.1002/mp.16208] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Proton radiography (PR) uses highly energetic proton beams to create images where energy loss is the main contrast mechanism. Water-equivalent path length (WEPL) measurements using flat panel PR (FP-PR) have potential for in vivo range verification. However, an accurate WEPL measurement via FP-PR requires irradiation with multiple energy layers, imposing high imaging doses. PURPOSE A FP-PR method is proposed for accurate WEPL determination based on a patient-specific imaging field with a reduced number of energies (n) to minimize imaging dose. METHODS Patient-specific FP-PRs were simulated and measured for a head and neck (HN) phantom. An energy selection algorithm estimated spot-wise the lowest energy required to cross the anatomy (Emin) using a water-equivalent thickness map. Starting from Emin, n was restricted to certain values (n = 26, 24, 22, …, 2 for simulations, n = 10 for measurements), resulting in patient-specific FP-PRs. A reference FP-PR with a complete set of energies was compared against patient-specific FP-PRs covering the whole anatomy via mean absolute WEPL differences (MAD), to evaluate the impact of the developed algorithm. WEPL accuracy of patient-specific FP-PRs was assessed using mean relative WEPL errors (MRE) with respect to measured multi-layer ionization chamber PRs (MLIC-PR) in the base of skull, brain, and neck regions. RESULTS MADs ranged from 2.1 mm (n = 26) to 21.0 mm (n = 2) for simulated FP-PRs, and 7.2 mm for measured FP-PRs (n = 10). WEPL differences below 1 mm were observed across the whole anatomy, except at the phantom surfaces. Measured patient-specific FP-PRs showed good agreement against MLIC-PRs, with MREs of 1.3 ± 2.0%, -0.1 ± 1.0%, and -0.1 ± 0.4% in the three regions of the phantom. CONCLUSION A method to obtain accurate WEPL measurements using FP-PR with a reduced number of energies selected for the individual patient anatomy was established in silico and validated experimentally. Patient-specific FP-PRs could provide means of in vivo range verification.
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Affiliation(s)
- Carmen Seller Oria
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jeffrey Free
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gabriel Guterres Marmitt
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Barbara Knäusl
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Sytze Brandenburg
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Antje C Knopf
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Department of Internal Medicine, Center for Integrated Oncology Cologne, University Hospital of Cologne, Cologne, Germany
| | - Arturs Meijers
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland
| | - Johannes A Langendijk
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Stefan Both
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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19
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Wang L, Alexander S, Mason S, Blasiak-Wal I, Harris E, McNair H, Lalondrelle S. Carpe Diem: Making the Most of Plan-of-the-Day for Cervical Cancer Radiation Therapy. Pract Radiat Oncol 2023; 13:132-147. [PMID: 36481683 DOI: 10.1016/j.prro.2022.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 10/26/2022] [Accepted: 11/03/2022] [Indexed: 12/12/2022]
Abstract
PURPOSE Radiation therapy is the key treatment for locally advanced cervical cancer. Organ motion presents a challenge to accurate targeting of external beam radiation therapy. The plan-of-the-day (PotD) adaptive approach is therefore an attractive option. We present our experience and the procedural steps required to implement PotD for cervix cancer. METHODS AND MATERIALS We reviewed relevant studies on organ motion and adaptive radiation therapy identified through a literature search and cross referencing. These included 10 dosimetric and 3 quality of life studies directly assessing the PotD approach to radiation therapy in cervix cancer. RESULTS Studies show improvements in target coverage and reduction of dose received by normal tissues and suggest improved toxicity. Clinical implementation of PotD has been slow because of a number of difficulties and uncertainties, which we discuss with the aim of helping teams to implement PotD at their center. CONCLUSIONS The PotD approach improves dosimetry and may improve toxicity. We describe a framework to assist with practical implementation.
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Affiliation(s)
- Lei Wang
- The Joint Department of Physics at the Institute of Cancer Research, Sutton, Surrey, United Kingdom.
| | - Sophie Alexander
- Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
| | - Sarah Mason
- The Joint Department of Physics at the Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Irena Blasiak-Wal
- The Joint Department of Physics at the Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Emma Harris
- The Joint Department of Physics at the Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Helen McNair
- Radiotherapy Department, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
| | - Susan Lalondrelle
- The Joint Department of Physics at the Institute of Cancer Research, Sutton, Surrey, United Kingdom
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20
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Abuhaimed A, Martin CJ. Assessment of organ and size-specific effective doses from cone beam CT (CBCT) in image-guided radiotherapy (IGRT) based on body mass index (BMI). Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2023.110889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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21
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Shimizu H, Sasaki K, Aoyama T, Iwata T, Kitagawa T, Kodaira T. Evaluation of a new acrylic-lead shielding device for peripheral dose reduction during cone-beam computed tomography. BJR Open 2022; 4:20220043. [PMID: 38525166 PMCID: PMC10958996 DOI: 10.1259/bjro.20220043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
Objective To clarify the peripheral dose changes, especially in the eye lens and thyroid gland regions, using an acrylic-lead shield in cone-beam computed tomography (CBCT). Methods The acrylic-lead shield consists of system walls and a system mat. The radiophotoluminescence glass dosemeter was set on the eye lens and thyroid gland regions on the RANDO phantom. The system mat was laid under the RANDO phantom ranging from the top of the head to the shoulders, and then, the system walls shielded the phantom's head. Additionally, the phantom was covered anteriorly with a band that had the same shielding ability as the system mat to cover the thyroid gland region. Protocols for CBCT imaging of the thoracic or pelvic region in clinical practice were used. The measurement was performed with and without the acrylic-lead shield. Results The dose to the eye lens region was reduced by 45% using the system wall. Conversely, the dose to the thyroid gland was unchanged. The use of the system mat reduced the dose to the thyroid gland region by 47%, and the dose to the eye lens was reduced by 22%. The dose to the eye lens region decreased to the background level using the system walls and mat. Conclusion The newly proposed device using an acrylic-lead shield reduced the peripheral dose in CBCT imaging. Advances in knowledge Attention is focused on managing peripheral dose in image-guided radiation therapy. The peripheral dose reduction using the acrylic-lead shield is a new proposal in radiotherapy that has never been studied.
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Affiliation(s)
- Hidetoshi Shimizu
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya, Aichi, Japan
| | - Koji Sasaki
- Graduate School of Radiological Technology, Gunma Prefectural College of Health Sciences, 323-1 Kamioki, Maebashi, Gunma, Japan
| | | | - Tohru Iwata
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya, Aichi, Japan
| | - Tomoki Kitagawa
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya, Aichi, Japan
| | - Takeshi Kodaira
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya, Aichi, Japan
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22
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Khan M, Sandhu N, Naeem M, Ealden R, Pearson M, Ali A, Honey I, Webster A, Eaton D, Ntentas G. Implementation of a comprehensive set of optimised CBCT protocols and validation through imaging quality and dose audit. Br J Radiol 2022; 95:20220070. [PMID: 36000497 PMCID: PMC9793481 DOI: 10.1259/bjr.20220070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Cone-beam computed tomography (CBCT) for radiotherapy treatment verification has increased in frequency; therefore, it is crucial to optimise image quality and radiation dose to patients. The aim of this study was to implement optimised CBCT protocols for the Varian TrueBeams for most tumour sites in adult patients. METHODS A combination of patient size-specific CBCT protocols from the literature and developed in-house was used. Scans taken before and after optimisation were compared by senior radiographers and physicists to evaluate how changes affected image quality and clinical usability for online image registration. The change in dose for each new CBCT protocol was compared to the Varian default. A clinical audit was performed following implementation to evaluate the changes in imaging dose for all patients receiving a CBCT during that period. RESULTS Ten CBCT protocols were introduced including head and neck and patient-size-specific thorax and pelvis/abdomen protocols. Scans from 102 patients with images before and after optimisation were assessed, none of the scans showed image quality changes compromising clinical usability and for some image quality was improved. Between November 2020 and June 2021, 1185 patients had CBCTs using the new protocols. The imaging dose was reduced for 52% of patients, remained the same for 37% and increased for 12%. CONCLUSIONS This study showed that substantial dose reductions and image quality improvements can be achieved with simple changes in the default settings of the Varian TrueBeam CBCT without affecting the radiographers' confidence in online image registration. ADVANCES IN KNOWLEDGE This study represents a comprehensive assessment and optimisation of CBCT protocols for most sites, validated on a large cohort of patients.
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Affiliation(s)
- Marina Khan
- Department of Radiotherapy, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Navneet Sandhu
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Marium Naeem
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Rebecca Ealden
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Michael Pearson
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Abdirzak Ali
- Department of Radiotherapy, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Ian Honey
- Department of Medical Physics, Guy’s & St Thomas’ NHS Foundation Trust, London, UK
| | - Amanda Webster
- Department of Radiotherapy, University College Hospital, London, UK
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23
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Al-Kabkabi A, Ramachandran P, Aamry A, Tamam N, Abuhadi NH, Johary Y, Aamri H, Sulieman A, Trapp J. Assessment of cone beam computed tomography image quality and dose for commonly used pre-sets in external beam radiotherapy. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Martin CJ, Abuhaimed A. Variations in size-specific effective dose with patient stature and beam width for kV cone beam CT imaging in radiotherapy. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2022; 42:031512. [PMID: 35917802 DOI: 10.1088/1361-6498/ac85fa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
The facilities now available on linear accelerators for external beam radiotherapy enable radiation fields to be conformed to the shapes of tumours with a high level of precision. However, in order for the treatment delivered to take advantage of this, the patient must be positioned on the couch with the same degree of accuracy. Kilovoltage cone beam computed tomography systems are now incorporated into radiotherapy linear accelerators to allow imaging to be performed at the time of treatment, and image-guided radiation therapy is now standard in most radiotherapy departments throughout the world. However, because doses from imaging are much lower than therapy doses, less effort has been put into optimising radiological protection of imaging protocols. Standard imaging protocols supplied by the equipment vendor are often used with little adaptation to the stature of individual patients, and exposure factors and field sizes are frequently larger than necessary. In this study, the impact of using standard protocols for imaging anatomical phantoms of varying size from a library of 193 adult phantoms has been evaluated. Monte Carlo simulations were used to calculate doses for organs and tissues for each phantom, and results combined in terms of size-specific effective dose (SED). Values of SED from pelvic scans ranged from 11 mSv to 22 mSv for male phantoms and 8 mSv to 18 mSv for female phantoms, and for chest scans from 3.8 mSv to 7.6 mSv for male phantoms and 4.6 mSv to 9.5 mSv for female phantoms. Analysis of the results showed that if the same exposure parameters and field sizes are used, a person who is 5 cm shorter will receive a size SED that is 3%-10% greater, while a person who is 10 kg lighter will receive a dose that is 10%-14% greater compared with the average size.
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Affiliation(s)
- C J Martin
- Department of Clinical Physics and Bioengineering, University of Glasgow, Gartnavel Royal Hospital, Glasgow G12 0XH, United Kingdom
| | - A Abuhaimed
- King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
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25
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Castelluccia A, Mincarone P, Tumolo MR, Sabina S, Colella R, Bodini A, Tramacere F, Portaluri M, Leo CG. Economic Evaluations of Magnetic Resonance Image-Guided Radiotherapy (MRIgRT): A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph191710800. [PMID: 36078513 PMCID: PMC9517760 DOI: 10.3390/ijerph191710800] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/17/2022] [Accepted: 08/20/2022] [Indexed: 05/06/2023]
Abstract
OBJECTIVES This review systematically summarizes the evidence on the economic impact of magnetic resonance image-guided RT (MRIgRT). METHODS We systematically searched INAHTA, MEDLINE, and Scopus up to March 2022 to retrieve health economic studies. Relevant data were extracted on study type, model inputs, modeling methods and economic results. RESULTS Five studies were included. Two studies performed a full economic assessment to compare the cost-effectiveness of MRIgRT with other forms of image-guided radiation therapy. One study performed a cost minimization analysis and two studies performed an activity-based costing, all comparing MRIgRT with X-ray computed tomography image-guided radiation therapy (CTIgRT). Prostate cancer was the target condition in four studies and hepatocellular carcinoma in one. Considering the studies with a full economic assessment, MR-guided stereotactic body radiation therapy was found to be cost effective with respect to CTIgRT or conventional or moderate hypofractionated RT, even with a low reduction in toxicity. Conversely, a greater reduction in toxicity is required to compete with extreme hypofractionated RT without MR guidance. CONCLUSIONS This review highlights the great potential of MRIgRT but also the need for further evidence, especially for late toxicity, whose reduction is expected to be the real added value of this technology.
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Affiliation(s)
- Alessandra Castelluccia
- Radiation Oncology, Department of Radiotherapy, Hospital “A. Perrino”, ASL Brindisi, 72100 Brindisi, Italy
| | - Pierpaolo Mincarone
- Institute for Research on Population and Social Policies, National Research Council, 72100 Brindisi, Italy
- MOVE-Mentis s.r.l., 47522 Cesena, Italy
- Correspondence: ; Tel.: +39-3289168745
| | - Maria Rosaria Tumolo
- Department of Biological and Environmental Sciences and Technology, University of Salento, 73100 Lecce, Italy
| | - Saverio Sabina
- MOVE-Mentis s.r.l., 47522 Cesena, Italy
- Institute of Clinical Physiology, National Research Council, 73100 Lecce, Italy
| | - Riccardo Colella
- Department of Engineering for Innovation, University of Salento, 73100 Lecce, Italy
| | - Antonella Bodini
- Institute for Applied Mathematics and Information Technologies “E. Magenes”, National Research Council, 20133 Milan, Italy
| | - Francesco Tramacere
- Radiation Oncology, Department of Radiotherapy, Hospital “A. Perrino”, ASL Brindisi, 72100 Brindisi, Italy
| | - Maurizio Portaluri
- Radiation Oncology, Department of Radiotherapy, Hospital “A. Perrino”, ASL Brindisi, 72100 Brindisi, Italy
| | - Carlo Giacomo Leo
- MOVE-Mentis s.r.l., 47522 Cesena, Italy
- Institute of Clinical Physiology, National Research Council, 73100 Lecce, Italy
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El Naqa I, Pogue BW, Zhang R, Oraiqat I, Parodi K. Image guidance for FLASH radiotherapy. Med Phys 2022; 49:4109-4122. [PMID: 35396707 PMCID: PMC9844128 DOI: 10.1002/mp.15662] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/10/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023] Open
Abstract
FLASH radiotherapy (FLASH-RT) is an emerging ultra-high dose (>40 Gy/s) delivery that promises to improve the therapeutic potential by limiting toxicities compared to conventional RT while maintaining similar tumor eradication efficacy. Image guidance is an essential component of modern RT that should be harnessed to meet the special emerging needs of FLASH-RT and its associated high risks in planning and delivering of such ultra-high doses in short period of times. Hence, this contribution will elaborate on the imaging requirements and possible solutions in the entire chain of FLASH-RT treatment, from the planning, through the setup and delivery with online in vivo imaging and dosimetry, up to the assessment of biological mechanisms and treatment response. In patient setup and delivery, higher temporal sampling than in conventional RT should ensure that the short treatment is delivered precisely to the targeted region. Additionally, conventional imaging tools such as cone-beam computed tomography will continue to play an important role in improving patient setup prior to delivery, while techniques based on magnetic resonance imaging or positron emission tomography may be extremely valuable for either linear accelerator (Linac) or particle FLASH therapy, to monitor and track anatomical changes during delivery. In either planning or assessing outcomes, quantitative functional imaging could supplement conventional imaging for more accurate utilization of the biological window of the FLASH effect, selecting for or verifying things such as tissue oxygen and existing or transient hypoxia on the relevant timescales of FLASH-RT delivery. Perhaps most importantly at this time, these tools might help improve the understanding of the biological mechanisms of FLASH-RT response in tumor and normal tissues. The high dose deposition of FLASH provides an opportunity to utilize pulse-to-pulse imaging tools such as Cherenkov or radiation acoustic emission imaging. These could provide individual pulse mapping or assessing the 3D dose delivery superficially or at tissue depth, respectively. In summary, the most promising components of modern RT should be used for safer application of FLASH-RT, and new promising developments could be advanced to cope with its novel demands but also exploit new opportunities in connection with the unique nature of pulsed delivery at unprecedented dose rates, opening a new era of biological image guidance and ultrafast, pulse-based in vivo dosimetry.
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Affiliation(s)
- Issam El Naqa
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
- Department of Medical Physics, University of Wisconsin-Madison, WI 53705, USA
| | - Rongxiao Zhang
- Giesel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Ibrahim Oraiqat
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
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Pham TT, Whelan B, Oborn BM, Delaney GP, Vinod S, Brighi C, Barton M, Keall P. Magnetic resonance imaging (MRI) guided proton therapy: A review of the clinical challenges, potential benefits and pathway to implementation. Radiother Oncol 2022; 170:37-47. [DOI: 10.1016/j.radonc.2022.02.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/09/2022] [Accepted: 02/25/2022] [Indexed: 10/18/2022]
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Gilling L, Ali O. Organ dose from Varian XI and Varian OBI systems are clinically comparable for pelvic CBCT imaging. Phys Eng Sci Med 2022; 45:279-285. [PMID: 35143026 DOI: 10.1007/s13246-021-01090-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 12/07/2021] [Indexed: 11/27/2022]
Abstract
Pelvic cone-beam computed tomography (CBCT) occurs daily in many radiotherapy clinics as a part of image-guided verification before treatment. These images are acquired by the use of ionizing radiation. The dose received by CBCT imaging is often not quantified in a patient's radiation therapy prescription. The purpose of this work was to quantify the dose from a TrueBeam XI pelvic CBCT imaging system. The dose to organs from this imaging protocol was then compared with published dose data for OBI v1.4 pelvic CBCT imaging. A model of the Varian XI imager was constructed using GATE Monte Carlo scripting language. The model was calibrated by correlation with experimental measurements. An IBA 3D water tank was used to perform relative dose measurements in water. An adult anthropomorphic Alderson phantom with embedded thermolumeniscent dosimeters was used to evaluate dose from prostate CBCT imaging. Following the calibration, the GATE model was used to simulate the dose from the XI pelvic CBCT protocol to the ICRP computational anthropomorphic phantom. The Monte Carlo model constructed in GATE was validated for use in dose estimates for the XI pelvic imaging protocol. The D50 and D10 values tabulated the pelvic CBCT protocol show that doses to organs in the pelvic region are comparable for both systems. For a clinician who intends to evaluate the dose to organs as a result of CBCT imaging of the pelvis from the TrueBeam XI system, for the purposes of treatment planning, the doses reported for OBI v1.4 given in AAPM TG-180 provide a valid estimate.
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Affiliation(s)
- Luke Gilling
- Medical Physics Department, Waikato District Health Board, Hamilton, New Zealand.
| | - Omer Ali
- Medical Physics Department, Waikato District Health Board, Hamilton, New Zealand
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O'Connell J, Bazalova‐Carter M. Investigation of image quality of MV and kV CBCT with low‐Z beams and high DQE detector. Med Phys 2022; 49:2334-2341. [DOI: 10.1002/mp.15503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 01/06/2022] [Accepted: 01/20/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jericho O'Connell
- Department of Physics and Astronomy University of Victoria Victoria BC V8W 2Y2 Canada
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PCXMC cone beam computed tomography dosimetry investigations. Phys Eng Sci Med 2022; 45:205-218. [PMID: 35072895 DOI: 10.1007/s13246-022-01103-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 01/07/2022] [Indexed: 10/19/2022]
Abstract
With cone beam computed tomography (CBCT) in image guided radiation therapy being amongst the most widely used imaging modalities, there has been an increasing interest in quantifying the concomitant dose and risk. Whilst there have been several studies on this topic, there remains a lack of standardisation and knowledge on dose variations and the impact of patient size. Recently, PCXMC (a Monte Carlo simulator) has been used to assess both the concomitant dose and dosimetric impact of patient size variations for CBCT. The scopes of these studies, however, have included only a limited range of imaging manufacturers, protocols, and patient sizes. An approach using PCXMC and MATLAB was developed to enable a generalised method for rapidly quantifying and formulating the concomitant dose as a function of patient size across numerous CBCT vendors and protocols. The method was investigated using the Varian on board imaging 1.6 default pelvis and pelvis spotlight protocols, for 94 adult and paediatric phantoms over 6 age groups with extensive height and mass variations. It was found that dose varies significantly with patient size, as much as doubling and halving the average for patients of lower and higher mass, respectively. These variations, however, can be formulated and accounted for using the method developed, across a wide range of patient sizes for all CBCT vendors and protocols. This will enable the development of a comprehensive catalogue to account for concomitant doses in almost any clinically relevant scenario.
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Le Deroff C, Berger L, Bellec J, Boissonnat G, Chesneau H, Chiavassa S, Desrousseaux J, Gempp S, Henry O, Jarril J, Lazaro D, Lefeuvre R, Passal V, Solinhac F, Lafond C, Delpon G. Monte Carlo-based software for 3D personalized dose calculations in image-guided radiotherapy. Phys Imaging Radiat Oncol 2022; 21:108-114. [PMID: 35243041 PMCID: PMC8885460 DOI: 10.1016/j.phro.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/28/2022] [Accepted: 02/11/2022] [Indexed: 11/23/2022] Open
Abstract
Monte Carlo calculations offer 3D personalized IGRT imaging dose distributions. Histogram dose volume were obtained for three anatomical sites and 5 imaging device. The image frequency is responsible for the cumulated dose to organs. Adapting the protocols to morphologies reduce the imaging dose.
Background and purpose Image-guided radiotherapy (IGRT) involves frequent in-room imaging sessions contributing to additional patient irradiation. The present work provided patient-specific dosimetric data related to different imaging protocols and anatomical sites. Material and methods We developed a Monte Carlo based software able to calculate 3D personalized dose distributions for five imaging devices delivering kV-CBCT (Elekta and Varian linacs), MV-CT (Tomotherapy machines) and 2D-kV stereoscopic images from BrainLab and Accuray. Our study reported the dose distributions calculated for pelvis, head and neck and breast cases based on dose volume histograms for several organs at risk. Results 2D-kV imaging provided the minimum dose with less than 1 mGy per image pair. For a single kV-CBCT and MV-CT, median dose to organs were respectively around 30 mGy and 15 mGy for the pelvis, around 7 mGy and 10 mGy for the head and neck and around 5 mGy and 15 mGy for the breast. While MV-CT dose varied sparsely with tissues, dose from kV imaging was around 1.7 times higher in bones than in soft tissue. Daily kV-CBCT along 40 sessions of prostate radiotherapy delivered up to 3.5 Gy to the femoral heads. The dose level for head and neck and breast appeared to be lower than 0.4 Gy for every organ in case of a daily imaging session. Conclusions This study showed the dosimetric impact of IGRT procedures. Acquisition parameters should therefore be chosen wisely depending on the clinical purposes and tailored to morphology. Indeed, imaging dose could be reduced up to a factor 10 with optimized protocols.
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Affiliation(s)
- Coralie Le Deroff
- Centre Eugène Marquis (Unicancer), Rennes, France
- Corresponding author.
| | - Lucie Berger
- Centre Jean Perrin (Unicancer), Clermont Ferrand, France
| | | | | | | | - Sophie Chiavassa
- Institut de Cancérologie de l’Ouest (Unicancer), Saint-Herblain, France
| | | | - Stéphanie Gempp
- Assistance Publique – Hôpitaux de Marseille, Marseille, France
| | | | - Jimmy Jarril
- Centre Jean Perrin (Unicancer), Clermont Ferrand, France
| | - Delphine Lazaro
- Université Paris-Saclay, CEA, List, F-91120 Palaiseau, France
| | | | - Vincent Passal
- Institut de Cancérologie de l’Ouest (Unicancer), Saint-Herblain, France
| | - Fanny Solinhac
- Assistance Publique – Hôpitaux de Marseille, Marseille, France
| | - Caroline Lafond
- Centre Eugène Marquis (Unicancer), Rennes, France
- Université de Rennes, Inserm, LTSI – UMR 1099, Rennes, France
| | - Gregory Delpon
- Institut de Cancérologie de l’Ouest (Unicancer), Saint-Herblain, France
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Liu W, Zhang L, Dai G, Zhang X, Li G, Yi Z. Deep Neural Network with Structural Similarity Difference and Orientation-based Loss for Position Error Classification in The Radiotherapy of Graves' Ophthalmopathy Patients. IEEE J Biomed Health Inform 2021; 26:2606-2614. [PMID: 34941537 DOI: 10.1109/jbhi.2021.3137451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Identifying position errors for Graves' ophthalmopathy (GO) patients using electronic portal imaging device (EPID) transmission fluence maps is helpful in monitoring treatment.} However, most of the existing models only extract features from dose difference maps computed from EPID images, which do not fully characterize all information of the positional errors. In addition, the position error has a three-dimensional spatial nature, which has never been explored in previous work. To address the above problems, a deep neural network (DNN) model with structural similarity difference and orientation-based loss is proposed in this paper, which consists of a feature extraction network and a feature enhancement network. To capture more information, three types of Structural SIMilarity (SSIM) sub-index maps are computed to enhance the luminance, contrast, and structural features of EPID images, respectively. These maps and the dose difference maps are fed into different networks to extract radiomic features. To acquire spatial features of the position errors, an orientation-based loss function is proposed for optimal training. It makes the data distribution more consistent with the realistic 3D space by integrating the error deviations of the predicted values in the left-right, superior-inferior, anterior-posterior directions. Experimental results on a constructed dataset demonstrate the effectiveness of the proposed model, compared with other related models and existing state-of-the-art methods.
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Svarc P, Hagen T, Waltenburg H, Andersson C, Bläckberg M, Baco E, Taudorf M, Røder MA, Lindgren H, Kløw NE, Lönn LB. Center experience and other determinants of patient radiation exposure during prostatic artery embolization: a retrospective study in three Scandinavian centers. Eur Radiol 2021; 32:2404-2413. [PMID: 34786614 DOI: 10.1007/s00330-021-08351-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/19/2021] [Accepted: 09/21/2021] [Indexed: 10/19/2022]
Abstract
OBJECTIVES To evaluate the effects of center experience and a variety of patient- and procedure-related factors on patient radiation exposure during prostatic artery embolization (PAE) in three Scandinavian centers with different PAE protocols and levels of experience. Understanding factors that influence radiation exposure is crucial in effective patient selection and procedural planning. METHODS Data were collected retrospectively for 352 consecutive PAE procedures from January 2015 to June 2020 at the three centers. Dose area product (DAP (Gy·cm2)) was selected as the primary outcome measure of radiation exposure. Multiple patient- and procedure-related explanatory variables were collected and correlated with the outcome variable. A multiple linear regression model was built to determine significant predictors of increased or decreased radiation exposure as reflected by DAP. RESULTS There was considerable variation in DAP between the centers. Intended unilateral PAE (p = 0.03) and each 10 additional patients treated (p = 0.02) were significant predictors of decreased DAP. Conversely, increased patient body mass index (BMI, p < 0.001), fluoroscopy time (p < 0.001), and number of digital subtraction angiography (DSA) acquisitions (p < 0.001) were significant predictors of increased DAP. CONCLUSIONS To minimize patient radiation exposure during PAE radiologists may, in collaboration with clinicians, consider unilateral embolization, pre-interventional CTA for procedure planning, using predominantly anteroposterior (AP) projections, and limiting the use of cone-beam CT (CBCT) and fluoroscopy. KEY POINTS • Growing center experience and intended unilateral embolization decrease patient radiation exposure during prostatic artery embolization. • Patient BMI, fluoroscopy time, and number of DSA acquisitions are associated with increased DAP during procedures. • Large variation in radiation exposure between the centers may reflect the use of CTA before and CBCT during the procedure.
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Affiliation(s)
- Petra Svarc
- Department of Radiology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark. .,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2100, Copenhagen, Denmark.
| | - Thijs Hagen
- Department of Radiology and Nuclear Medicine, Oslo University Hospital, Kirkeveien 166, Oslo, Norway
| | - Hanne Waltenburg
- Radiation Protection, Danish Health Authority, Knapholm 7, 2730, Herlev, Denmark
| | - Christian Andersson
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Helsingborg Hospital, Charlotte Yhlens gata 10, 252 23, Helsingborg, Sweden
| | - Mats Bläckberg
- Department of Urology, Helsingborg Hospital, Charlotte Yhlens gata 10, 252 23, Helsingborg, Sweden.,Department of Clinical Sciences, Faculty of Medicine, Lund University, Box 188, 221 00, Lund, Sweden
| | - Eduard Baco
- Department of Urology, Division of Surgery, Inflammation and Transplantation, Oslo University Hospital, Kirkeveien 166, Oslo, Norway
| | - Mikkel Taudorf
- Department of Radiology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2100, Copenhagen, Denmark
| | - Martin Andreas Røder
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2100, Copenhagen, Denmark.,Department of Urology, Rigshospitalet, Copenhagen Prostate Cancer Center, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Hans Lindgren
- Department of Clinical Sciences, Faculty of Medicine, Lund University, Box 188, 221 00, Lund, Sweden.,Department of Surgery, Section of Interventional Radiology, Helsingborg Hospital, Charlotte Yhlens gata 10, 252 23, Helsingborg, Sweden
| | - Nils-Einar Kløw
- Department of Radiology and Nuclear Medicine, Oslo University Hospital, Kirkeveien 166, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Kirkeveien 166, Oslo, Norway
| | - Lars Birger Lönn
- Department of Radiology, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2100, Copenhagen, Denmark
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Nazir S, Bert J, Fayad H, Visvikis D. Surface imaging for real-time patient positioning in external radiation therapy. Med Phys 2021; 48:8037-8044. [PMID: 34669989 DOI: 10.1002/mp.15300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/20/2021] [Accepted: 10/11/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE In the last few years, there has been a growing interest in surface imaging for patient positioning in external radiation therapy. The aim of this study is to evaluate the accuracy of daily patient positioning using the Azure Kinect surface imaging. METHODS A total of 50 fractions in 10 patients including lung, pelvic, and head and neck tumors were analyzed in real time. A rigid registration algorithm, based on the iterative closest point (ICP) approach, is employed to estimate the patient position in 6 degrees of freedom (DOF). This position is compared to the reference values obtained by the radiograph imaging. The mean setup error and its standard deviation were calculated for all measured fractions. RESULTS The positioning error showed 1.1 ± 1.1 mm in lateral, 1.8 ± 2.1 mm in longitudinal, and 0.8 ± 1.1 mm in vertical, and 0.3°± 0.4° in yaw, 0.2°± 0.2° in pitch, and 0.2°± 0.2° in roll directions. The larger setup error occurred in pelvic regions. CONCLUSION We have evaluated in a radiotherapy set-up considering different patient anatomical locations, a depth measurement based surface imaging solution for patient positioning considering the 6 DOF couch motion. We showed that the proposed solution allows an accurate patient positioning without the need for patient markings or the use of additional radiation dose.
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Affiliation(s)
- Souha Nazir
- INSERM, UMR1101, LaTIM, University of Brest, Brest, France
| | - Julien Bert
- INSERM, UMR1101, LaTIM, University of Brest, Brest, France
| | - Hadi Fayad
- Hamad Medical Corporation OHS, PET/CT Center, Doha, Qatar
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Dai G, Zhang X, Liu W, Li Z, Wang G, Liu Y, Xiao Q, Duan L, Li J, Song X, Li G, Bai S. Analysis of EPID Transmission Fluence Maps Using Machine Learning Models and CNN for Identifying Position Errors in the Treatment of GO Patients. Front Oncol 2021; 11:721591. [PMID: 34595115 PMCID: PMC8476908 DOI: 10.3389/fonc.2021.721591] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/30/2021] [Indexed: 02/05/2023] Open
Abstract
Purpose To find a suitable method for analyzing electronic portal imaging device (EPID) transmission fluence maps for the identification of position errors in the in vivo dose monitoring of patients with Graves' ophthalmopathy (GO). Methods Position errors combining 0-, 2-, and 4-mm errors in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions in the delivery of 40 GO patient radiotherapy plans to a human head phantom were simulated and EPID transmission fluence maps were acquired. Dose difference (DD) and structural similarity (SSIM) maps were calculated to quantify changes in the fluence maps. Three types of machine learning (ML) models that utilize radiomics features of the DD maps (ML 1 models), features of the SSIM maps (ML 2 models), and features of both DD and SSIM maps (ML 3 models) as inputs were used to perform three types of position error classification, namely a binary classification of the isocenter error (type 1), three binary classifications of LR, SI, and AP direction errors (type 2), and an eight-element classification of the combined LR, SI, and AP direction errors (type 3). Convolutional neural network (CNN) was also used to classify position errors using the DD and SSIM maps as input. Results The best-performing ML 1 model was XGBoost, which achieved accuracies of 0.889, 0.755, 0.778, 0.833, and 0.532 in the type 1, type 2-LR, type 2-AP, type 2-SI, and type 3 classification, respectively. The best ML 2 model was XGBoost, which achieved accuracies of 0.856, 0.731, 0.736, 0.949, and 0.491, respectively. The best ML 3 model was linear discriminant classifier (LDC), which achieved accuracies of 0.903, 0.792, 0.870, 0.931, and 0.671, respectively. The CNN achieved classification accuracies of 0.925, 0.833, 0.875, 0.949, and 0.689, respectively. Conclusion ML models and CNN using combined DD and SSIM maps can analyze EPID transmission fluence maps to identify position errors in the treatment of GO patients. Further studies with large sample sizes are needed to improve the accuracy of CNN.
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Affiliation(s)
- Guyu Dai
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangbin Zhang
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Wenjie Liu
- Machine Intelligence Laboratory, College of Computer Science, Sichuan University, Chengdu, China
| | - Zhibin Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Guangyu Wang
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yaxin Liu
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Qing Xiao
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Lian Duan
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Jing Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xinyu Song
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Guangjun Li
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Sen Bai
- Department of Radiation Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
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An international survey of imaging practices in radiotherapy. Phys Med 2021; 90:53-65. [PMID: 34562809 DOI: 10.1016/j.ejmp.2021.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 12/25/2022] Open
Abstract
Improvements in delivery of radiation dose to target tissues in radiotherapy have increased the need for better image quality and led to a higher frequency of imaging patients. Imaging for treatment planning extends to function and motion assessment and devices are incorporated into medical linear accelerators (linacs) so that regions of tissue can be imaged at time of treatment delivery to ensure dose distributions are delivered as accurately as possible. A survey of imaging in 97 radiotherapy centres in nine countries on six continents has been undertaken with an on-line questionnaire administered through the International Commission on Radiological Protection mentorship programme to provide a snapshot of imaging practices. Responses show that all centres use CT for planning treatments and many utilise additional information from magnetic resonance imaging and positron emission tomography scans. Most centres have kV cone beam CT attached to at least some linacs and use this for the majority of treatment fractions. The imaging options available declined with the human development index (HDI) of the country, and the frequency of imaging during treatment depended more on country than treatment site with countries having lower HDIs imaging less frequently. The country with the lowest HDI had few kV imaging facilities and relied on MV planar imaging intermittently during treatment. Imaging protocols supplied by vendors are used in most centres and under half adapt exposure conditions to individual patients. Recording of patient doses, a knowledge of which is important in optimisation of imaging protocols, was limited primarily to European countries.
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Optimisation of CT scan parameters to increase the accuracy of gross tumour volume identification in brain radiotherapy. JOURNAL OF RADIOTHERAPY IN PRACTICE 2021. [DOI: 10.1017/s1460396920000436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractAim:This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed.Materials and methods:A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method.Results:Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%).Findings:CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment.
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Borm KJ, Junker Y, Düsberg M, Devečka M, Münch S, Dapper H, Oechsner M, Combs SE. Impact of CBCT frequency on target coverage and dose to the organs at risk in adjuvant breast cancer radiotherapy. Sci Rep 2021; 11:17378. [PMID: 34462489 PMCID: PMC8405651 DOI: 10.1038/s41598-021-96836-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022] Open
Abstract
The current study aims to assess the effect of cone beam computed tomography (CBCT) frequency during adjuvant breast cancer radiotherapy with simultaneous integrated boost (SIB) on target volume coverage and dose to the organs at risk (OAR). 50 breast cancer patients receiving either non-hypofractionated or hypofractionated radiotherapy after lumpectomy including a SIB to the tumor bed were selected for this study. All patients were treated in volumetric modulated arc therapy (VMAT) technique and underwent daily CBCT imaging. In order to estimate the delivered dose during the treatment, the applied fraction doses were recalculated on daily CBCT scans and accumulated using deformable image registration. Based on a total of 2440 dose recalculations, dose coverage in the clinical target volumes (CTV) and OAR was compared depending on the CBCT frequency. The estimated delivered dose (V95%) for breast-CTV and SIB-CTV was significantly lower than the planned dose distribution, irrespective of the CBCT-frequency. Between daily CBCT and CBCT on alternate days, no significant dose differences were found regarding V95% for both, breast-CTV and SIB-CTV. Dose distribution in the OAR was similar for both imaging protocols. Weekly CBCT though led to a significant decrease in dose coverage compared to daily CBCT and a small but significant dose increase in most OAR. Daily CBCT imaging might not be necessary to ensure adequate dose coverage in the target volumes while efficiently sparing the OAR during adjuvant breast cancer radiotherapy with SIB.
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Affiliation(s)
- Kai J Borm
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany.
| | - Yannis Junker
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany
| | - Mathias Düsberg
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany
| | - Michal Devečka
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany
| | - Stefan Münch
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany
| | - Hendrik Dapper
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany
| | - Markus Oechsner
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany
| | - Stephanie E Combs
- Department of Radiation Oncology, Klinikum Rechts Der Isar, Medical School, Technical University Munich, Ismaningerstraße 22, 81675, Munich, Germany.,Deutsches Konsortium Für Translationale Krebsforschung (DKTK)-Partner Site Munich, Munich, Germany.,Institute of Radiation Medicine, Helmholtzzentrum München, Munich, Germany
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Ordóñez-Sanz C, Cowen M, Shiravand N, MacDougall ND. CBCT imaging: a simple approach for optimising and evaluating concomitant imaging doses, based on patient-specific attenuation, during radiotherapy pelvis treatment. Br J Radiol 2021; 94:20210068. [PMID: 34282947 PMCID: PMC8523193 DOI: 10.1259/bjr.20210068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objectives: A simple, robust method, for optimising cone-beam CT (CBCT) dose and image quality for pelvis treatment, based on patient-specific attenuation. Methods: Methods were investigated for grouping patients into four imaging categories (small [S], medium [M], large [L], extra large [XL]), based on planning-CT CTDIvol, and phantoms constructed to represent each group. CBCTs with varying kV, mA and ms honed in on the best settings, with a bladder noise of 25 HU. A patient pilot study clinically verified the new imaging settings. Results: The planning CTDIvol is a reliable method for grouping patients. Phantom measurements from the S, M and L groups show doses significantly reduced (19–83% reduction), whilst the XL group required an increase of 39%. Phantom TLD measurements showed the number of scans needed to increase rectal organ at risk (OAR) dose by 1 Gy was 143 (S group) and 50 (M group). Images were qualitatively assessed as sufficient by clinicians. Conclusion: Patient-specific CBCT modes are in use clinically with dose reductions across all modes except Pelvis XL, keeping doses ALARP and images optimal. Consideration of OAR doses controls the number of CBCTs allowed to ensure adherence to OAR tolerance. Reporting CBCT doses in “scans per Gray” allows clinicians to make informed decisions regarding the imaging schedule and concomitant doses. Advances in knowledge: Patient grouping at planning CT, using CTDIvol, allows for CBCT imaging protocols to be selected based on patient specific attenuation. Reporting OAR doses in terms of “scans per Gray” allows translation of imaging dose risk to the Oncologist.
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Affiliation(s)
| | - Mark Cowen
- North West Anglia NHS Foundation Trust, England, UK
| | - Neda Shiravand
- Radiotherapy Physics, St Bartholomew's Hospital, London, UK
| | - Niall D MacDougall
- Radiotherapy Physics, St Bartholomew's Hospital, London, UK.,Barts Cancer Institute, Queen Mary University of London, London, UK
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O'Connell J, Bazalova-Carter M. fastCAT: Fast cone beam CT (CBCT) simulation. Med Phys 2021; 48:4448-4458. [PMID: 34053094 DOI: 10.1002/mp.15007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To develop fastCAT, a fast cone-beam computed tomography (CBCT) simulator. fastCAT uses pre-calculated Monte Carlo (MC) CBCT phantom-specific scatter and detector response functions to reduce simulation time for megavoltage (MV) and kilovoltage (kV) CBCT imaging. METHODS Pre-calculated x-ray beam energy spectra, detector optical spread functions and energy deposition, and phantom scatter kernels are combined with GPU raytracing to produce CBCT volumes. MV x-ray beam spectra are simulated with EGSnrc for 2.5- and 6 MeV electron beams incident on a variety of target materials and kV x-ray beam spectra are calculated analytically for an x-ray tube with a tungsten anode. Detectors were modeled in Geant4 extended by Topas and included optical transport in the scintillators. Two MV detectors were modeled-a standard Varian AS1200 GOS detector and a novel CWO high detective quantum efficiency detector. A kV CsI detector was also modeled. Energy-dependent scatter kernels were created in Topas for two 16 cm diameter phantoms: A Catphan 515 contrast phantom and an anthropomorphic head phantom. The Catphan phantom contained inserts of 1-5 mm in diameter of six different tissue types: brain, deflated lung, compact and cortical bone, adipose, and B-100. RESULTS fastCAT simulations retain high fidelity to measurements and MC simulations: MTF curves were within 3.5% and 1.2% of measured values for the CWO and GOS detectors, respectively. HU values and CNR in a fastCAT Catphan 515 simulation were seen to be within 95% confidence intervals of an equivalent MC simulation for all of the tissues with root mean squared errors less than 16 HU and 1.6 in HU values and CNR comparisons, respectively. The anthropomorphic head phantom CWO detector CBCT image resulted in much higher tissue contrast and lower noise compared to the GOS detector CBCT image. A fastCAT simulation of the Catphan 515 module with an image size of 1024 × 1024 × 10 voxels took 61 s on a GPU while the equivalent Topas MC was estimated to take more than 0.3 CPU years. CONCLUSIONS We present an open source fast CBCT simulation with high fidelity to MC simulations. The fastCAT python package can be found at https://github.com/jerichooconnell/fastCAT.git.
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Affiliation(s)
- Jericho O'Connell
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 5C2, Canada
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Singh T, Lee J, Zahurak M, Bae HJ, Habtu T, Hobbs R, Le Y, Burdette EC, Song DY. Superior Postimplant Dosimetry Achieved Using Dynamic Intraoperative Dosimetry for Permanent Prostate Brachytherapy. Pract Radiat Oncol 2021; 11:264-271. [PMID: 33722782 DOI: 10.1016/j.prro.2021.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Low-dose-rate brachytherapy is a highly effective treatment modality for prostate carcinoma, but postimplant dosimetry quality is essential and correlated with likelihood of treatment success. Registered ultrasound and fluoroscopy (iRUF) can facilitate real-time intraoperative monitoring and plan adaptation, with the aim of attaining superior dosimetric outcomes. The purpose of this research was to compare clinical postimplant dosimetric results of iRUF-guided brachytherapy against brachytherapy using standard ultrasound-guided intraoperative dosimetry methods. METHODS AND MATERIALS We analyzed postimplant dosimetry in 292 patients treated with Pd-103 between January 2007 and December 2018. All patients had postimplant dosimetry measured on day 0 to 1 using fused magnetic resonance/computed tomography assessment. Fifty-two patients were treated in 2 prospective clinical trials using iRUF intraoperative dosimetry, including 6 patients in a pilot study and 46 treated in a phase 2 study. Postimplant dosimetry in iRUF-treated patients was compared with dosimetry from 240 patients treated using standard (real-time ultrasound) intraoperative seed tracking. RESULTS For every parameter measuring dose coverage to the prostate, iRUF patients had significantly higher values, irrespective of adjustment for year of treatment. In adjusted analyses, parameters of dose to urethra and rectum were not significantly higher among iRUF-treated patients. CONCLUSIONS Use of iRUF intraoperative dosimetry was associated with improved postimplant dose coverage in prostate, without associated increases in doses to urethra or rectum.
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Affiliation(s)
- Tanmay Singh
- Departments of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Junghoon Lee
- Departments of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Marianna Zahurak
- Departments of Oncology, Biostatistics and Bioinformatics Division, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hee Joon Bae
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Tamey Habtu
- Merit Health Leadership Academy, Baltimore, Maryland
| | - Robert Hobbs
- Departments of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yi Le
- Department of Radiation Oncology, Indiana University, Bloomington, Indiana
| | | | - Daniel Y Song
- Departments of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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Low-dose CBCT reconstruction via joint non-local total variation denoising and cubic B-spline interpolation. Sci Rep 2021; 11:3681. [PMID: 33574477 PMCID: PMC7878746 DOI: 10.1038/s41598-021-83266-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/28/2021] [Indexed: 12/11/2022] Open
Abstract
This study develops an improved Feldkamp–Davis–Kress (FDK) reconstruction algorithm using non-local total variation (NLTV) denoising and a cubic B-spline interpolation-based backprojector to enhance the image quality of low-dose cone-beam computed tomography (CBCT). The NLTV objective function is minimized on all log-transformed projections using steepest gradient descent optimization with an adaptive control of the step size to augment the difference between a real structure and noise. The proposed algorithm was evaluated using a phantom data set acquired from a low-dose protocol with lower milliampere-seconds (mAs).The combination of NLTV minimization and cubic B-spline interpolation rendered the enhanced reconstruction images with significantly reduced noise compared to conventional FDK and local total variation with anisotropic penalty. The artifacts were remarkably suppressed in the reconstructed images. Quantitative analysis of reconstruction images using low-dose projections acquired from low mAs showed a contrast-to-noise ratio with spatial resolution comparable to images reconstructed using projections acquired from high mAs. The proposed approach produced the lowest RMSE and the highest correlation. These results indicate that the proposed algorithm enables application of the conventional FDK algorithm for low mAs image reconstruction in low-dose CBCT imaging, thereby eliminating the need for more computationally demanding algorithms. The substantial reductions in radiation exposure associated with the low mAs projection acquisition may facilitate wider practical applications of daily online CBCT imaging.
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Organ dose and radiogenic risk in dental cone-beam computed tomography examinations. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Daily computed tomography image guidance: Dosimetric advantages outweigh low-dose radiation exposure for treatment of mediastinal lymphoma. Radiother Oncol 2020; 152:14-18. [DOI: 10.1016/j.radonc.2020.06.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/29/2020] [Accepted: 06/19/2020] [Indexed: 11/23/2022]
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Zhao Y, Diao P, Zhang D, Wu J, Xin X, Fontanarosa D, Liu M, Li J, Orlandini LC. Impact of Positioning Errors on the Dosimetry of Breath-Hold-Based Volumetric Arc Modulated and Tangential Field-in-Field Left-Sided Breast Treatments. Front Oncol 2020; 10:554131. [PMID: 33194616 PMCID: PMC7658584 DOI: 10.3389/fonc.2020.554131] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 10/07/2020] [Indexed: 12/11/2022] Open
Abstract
Heart diseases and cardiovascular events are well-known side effects in left-sided breast irradiation. Deep inspiration breath hold (BH) combined with fast delivery techniques such as volumetric modulated arc therapy (VMAT) or tangential field-in-field (TFiF) can serve as a valuable solution to reduce the dose to the heart. This study aims to compare the impact of positioning errors in VMAT and TFiF plans for BH left-sided breast treatments. Fifteen left-sided breast patients treated in BH with TFiF technique were included in this retrospective study. For each patient, a second plan with VMAT technique was optimized. Eighteen setup variations were introduced in each of these VMAT and TFiF reference plans, shifting the isocenter along six different directions by 3, 5, and 10 mm. A total of 540 perturbed plans, 270 for each technique, were recalculated and analyzed. The dose distributions on the target and organs at risk obtained in the different perturbed scenarios were compared with the reference scenarios, using as dosimetric endpoints the dose-volume histograms (DVH). The results were compared using the Wilcoxon test. Comparable plan quality was obtained for the reference VMAT and TFiF plans, except for low doses to organs at risk for which higher values (p < 0.05) were obtained for VMAT plans. For TFiF plans, perturbations of the isocenter position of 3, 5, or 10 mm produced mean deviations of the target DVH dosimetric parameters up to -0.5, -1.0, and -5.2%, respectively; VMAT plans were more sensitive to positioning errors resulting in mean deviations up to -0.5, -4.9, and -13.9%, respectively, for the same magnitude of the above mentioned perturbations. For organs at risk, only perturbations along the left, posterior, and inferior directions resulted in dose increase with a maximum deviation of +2% in the DVH dosimetric parameters. A notable exception were low doses to the left lung and heart for 10 mm isocenter shifts for which the mean differences ranged between +2.7 and +4.1%. Objective information on how external stresses affect the dosimetry of the treatment is the first step towards personalized radiotherapy.
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Affiliation(s)
- Yanqun Zhao
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
| | - Peng Diao
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Da Zhang
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
| | - Juxiang Wu
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
| | - Xin Xin
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
| | - Davide Fontanarosa
- School of Clinical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Min Liu
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
| | - Jie Li
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
| | - Lucia Clara Orlandini
- Department of Radiation Oncology, Sichuan Cancer Hospital and Research Institute, Chengdu, China
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China
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Hua CH, Vern-Gross TZ, Hess CB, Olch AJ, Alaei P, Sathiaseelan V, Deng J, Ulin K, Laurie F, Gopalakrishnan M, Esiashvili N, Wolden SL, Krasin MJ, Merchant TE, Donaldson SS, FitzGerald TJ, Constine LS, Hodgson DC, Haas-Kogan DA, Mahajan A, Laack N, Marcus KJ, Taylor PA, Ahern VA, Followill DS, Buchsbaum JC, Breneman JC, Kalapurakal JA. Practice patterns and recommendations for pediatric image-guided radiotherapy: A Children's Oncology Group report. Pediatr Blood Cancer 2020; 67:e28629. [PMID: 32776500 PMCID: PMC7774502 DOI: 10.1002/pbc.28629] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 06/16/2020] [Accepted: 07/19/2020] [Indexed: 12/18/2022]
Abstract
This report by the Radiation Oncology Discipline of Children's Oncology Group (COG) describes the practice patterns of pediatric image-guided radiotherapy (IGRT) based on a member survey and provides practice recommendations accordingly. The survey comprised of 11 vignettes asking clinicians about their recommended treatment modalities, IGRT preferences, and frequency of in-room verification. Technical questions asked physicists about imaging protocols, dose reduction, setup correction, and adaptive therapy. In this report, the COG Radiation Oncology Discipline provides an IGRT modality/frequency decision tree and the expert guidelines for the practice of ionizing image guidance in pediatric radiotherapy patients.
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Affiliation(s)
- Chia-ho Hua
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, Tennessee
| | | | - Clayton B. Hess
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
- Department of Radiation Oncology, Emory University, Atlanta, Georgia
| | - Arthur J. Olch
- Department of Radiation Oncology, University of Southern California and Children’s Hospital of Los Angeles, Los Angeles, California
| | - Parham Alaei
- Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota
| | | | - Jun Deng
- Department of Therapeutic Radiology, Yale University, New Haven, Connecticut
| | - Kenneth Ulin
- Department of Radiation Oncology, University of Massachusetts, Worcester, Massachusetts
| | - Fran Laurie
- Department of Radiation Oncology, University of Massachusetts, Worcester, Massachusetts
| | | | - Natia Esiashvili
- Department of Radiation Oncology, Emory University, Atlanta, Georgia
| | - Suzanne L. Wolden
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Matthew J. Krasin
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, Tennessee
| | - Thomas E Merchant
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, Tennessee
| | - Sarah S. Donaldson
- Department of Radiation Oncology, Stanford University, Stanford, California
| | - Thomas J. FitzGerald
- Department of Radiation Oncology, University of Massachusetts, Worcester, Massachusetts
| | - Louis S. Constine
- Department of Radiation Oncology, University of Rochester, Rochester, New York
| | - David C. Hodgson
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Daphne A. Haas-Kogan
- Department of Radiation Oncology, Dana Farber Cancer Institute/Boston Children’s Hospital, Boston, Massachusetts
| | - Anita Mahajan
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Nadia Laack
- Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota
| | - Karen J. Marcus
- Department of Radiation Oncology, Dana Farber Cancer Institute/Boston Children’s Hospital, Boston, Massachusetts
| | - Paige A Taylor
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Verity A Ahern
- Department of Radiation Oncology, Children’s Hospital at Westmead, Sydney, Australia
| | - David S. Followill
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jeffrey C. Buchsbaum
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, Maryland
| | - John C. Breneman
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, Ohio
| | - John A. Kalapurakal
- Department of Radiation Oncology, Northwestern University, Chicago, Illinois
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Takei Y, Monzen H, Tamura M, Doi H, Nishimura Y. Dose reduction potential of using gold fiducial markers for kilovoltage image-guided radiotherapy. J Appl Clin Med Phys 2020; 21:151-157. [PMID: 32959957 PMCID: PMC7592977 DOI: 10.1002/acm2.13023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 12/19/2022] Open
Abstract
This study aimed to evaluate the possibility of reducing the imaging dose for image-guided radiotherapy by using planar kilovoltage orthogonal imaging and fiducial markers (kV-FM). We tested kilovoltage planar images under clinical imaging conditions for the pelvis (75 kVp, 200 mA, 50 ms) at a decreasing tube current (from 200 to 10 mA). Imaging doses were measured with a semiconductor detector. The visibility of the kV-FM, aspects of image quality (spatial resolution, low contrast resolution), and the resultant image registration reproducibility were evaluated using various shapes (folded, linear, tadpole-like) of fiducial markers containing 0.5% iron [Gold Anchor™ (GA); Naslund Medical AB, Huddinge, Sweden]. The GA phantom was created by placing these variously shaped GAs in an agar phantom. The imaging doses with 200 and 10 mA were approximately 0.74 and 0.04 mGy and they were correlated to the tube current (R2 = 0.999). Regardless of the marker's shape, the GA phantom ensured visibility even when the tube current was reduced to the minimum value (10 mA). The low contrast resolution was gradually decreased at less than 50 mA, but the spatial resolution did not change. Although the auto-registration function could not be used, manual-registration could be achieved with an accuracy of within 1 mm, even when the imaging dose was reduced to 1/20 of the clinical imaging condition for the pelvis. When using the GA as the fiducial marker, the imaging dose could be reduced to 1/20 of that used clinically while maintaining the accuracy of manual-registration using the kV-FM for image-guided radiotherapy of the pelvis.
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Affiliation(s)
- Yoshiki Takei
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
- Department of Radiology, Kindai University Nara Hospital, Ikoma, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Japan
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Japan
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Eren MF, Çolpan Öksüz D, Sayan M, Karaçam S, Vergalasova I, Ay Eren A, Öner Dinçbaş F. Comparison of kV Orthogonal Radiographs and kV-Cone-Beam Computed Tomography Image-Guided Radiotherapy Methods With and Without Implanted Fiducials in Prostate Cancer. Cureus 2020; 12:e9916. [PMID: 32850264 PMCID: PMC7445001 DOI: 10.7759/cureus.9916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Introduction The aim of this study is to investigate the performance of kilovoltage (kV) cone-beam computed tomography (CBCT)-based adjustments with respect to kV-orthogonal fiducial marker-based matching in a group of patients with prostate cancer. Methods Twenty prostate cancer patients were evaluated retrospectively: 10 with implanted fiducial markers and 10 without. Daily orthogonal kV imaging was recorded prior to radiation delivery. Images were evaluated in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions by matching either the implanted fiducials or going off bony anatomy, depending on the presence or absence of markers, respectively. Cone-beam computed tomography (CBCT) imaging was also subsequently acquired and images were aligned with the planning CT. The couch shifts were calculated and the patient's position was adjusted accordingly. Standard deviations and random errors were also computed. Pearson correlation and Bland-Altman analysis were performed to evaluate relationships between the datasets. Results A total of 240 images were evaluated. The Pearson correlation coefficient for shifts applied to patients with markers using kV and CBCT was 88.3%, 87.8%, and 94.5% for the LR, AP, and SI directions, respectively. For those without markers, the respective values for the LR, AP, and SI directions were: 39.3%, 22.4%, and 3.7%. A Bland-Altman analysis comparing kV and CBCT in patients with markers, revealed R2 values of 0.152, 0.282, and 0.097 in the LR, AP, and SI directions, respectively. The R2 values for patients without markers were 0.008, 0.01, and 0.057, in the LR, AP, and SI directions, respectively. Conclusions Our data suggest that CBCT can be a viable option for image-guidance in clinical settings where fiducial markers are unavailable such as situations of inaccessibility or medical contraindications.
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Affiliation(s)
- Mehmet F Eren
- Radiation Oncology, Marmara University Pendik Education and Research Hospital, Istanbul, TUR
| | - Didem Çolpan Öksüz
- Radiation Oncology, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpaşa, Istanbul, TUR
| | - Mutlay Sayan
- Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, USA
| | - Songül Karaçam
- Radiation Oncology, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpaşa, Istanbul, TUR
| | - Irina Vergalasova
- Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, USA
| | - Ayfer Ay Eren
- Radiation Oncology, Saglik Bilimleri University, Kartal Dr. Lutfi Kirdar Education and Research Hospital, Istanbul, TUR
| | - Fazilet Öner Dinçbaş
- Radiation Oncology, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpaşa, Istanbul, TUR
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Boissonnat G, Chesneau H, Barat E, Dautremer T, Garcia-Hernandez JC, Lazaro D. Validation of histogram-based virtual source models for different IGRT kV-imaging systems. Med Phys 2020; 47:4531-4542. [PMID: 32497267 DOI: 10.1002/mp.14311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Image-guided radiotherapy (IGRT) improves tumor control but its intensive use may entrain late side effects caused by the additional imaging doses. There is a need to better quantify the additional imaging doses, so they can be integrated in the therapeutic workflow. Currently, no dedicated software enables to compute patient-specific imaging doses on a wide range of systems and protocols. As a first step toward this objective, we propose a common methodology to model four different kV-imaging systems used in radiotherapy (Varian's OBI, Elekta's XVI, Brainlab's ExacTrac, and Accuray's Cyberknife) using a new type of virtual source model based on Monte Carlo calculations. METHODS We first describe our method to build a simplified description of the photon output, or virtual source models (VSMs), of each imaging system. Instead of being constructed using measurement data, as it is most commonly the case, our VSM is used as the summary of the phase-space files (PSFs) resulting from a first Monte Carlo simulation of the considered x-ray tube. Second, the VSM is used as a photon generator for a second MC simulation in which we compute the dose. Then, the proposed VSM is thoroughly validated against standard MC simulation using PSFs on the XVI system. Last, each modeled system is compared to profiles and depth-dose-curve measurements performed in homogeneous phantom. RESULTS Comparisons between PSF-based and VSM-based calculations highlight that VSMs could provide equivalent dose results (within 1% of difference) than PSFs inside the imaging field-of-view (FOV). In contrast, VSMs tend to underestimate (for up to 20%) calculated doses outside of the imaging FOV due to the assumptions underlying the VSM construction. In addition, we showed that the use of VSMs allows reducing calculation time by at least a factor of 2.8. Indeed, for identical simulation times, statistical uncertainties on dose distributions computed using VSMs were much lower than those obtained from PSF-based calculations. CONCLUSIONS For each of the four imaging systems, VSMs were successfully validated against measurements in homogeneous phantoms, and are therefore ready to be used for future preclinical studies in heterogeneous or anthropomorphic phantoms. The cross system modeling methodology developed here should enable, later on, to estimate precisely and accurately patient-specific 3D dose maps delivered during a large range of kV-imaging procedures.
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Affiliation(s)
- G Boissonnat
- CEA, LIST, System Modelling and Simulation Lab, Gif-sur-Yvette, F-91191, France
| | - H Chesneau
- CEA, LIST, System Modelling and Simulation Lab, Gif-sur-Yvette, F-91191, France
| | - E Barat
- CEA, LIST, System Modelling and Simulation Lab, Gif-sur-Yvette, F-91191, France
| | - T Dautremer
- CEA, LIST, System Modelling and Simulation Lab, Gif-sur-Yvette, F-91191, France
| | | | - D Lazaro
- CEA, LIST, System Modelling and Simulation Lab, Gif-sur-Yvette, F-91191, France
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50
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Baptista M, Di Maria S, Vieira S, Pereira J, Pereira M, Vaz P. Organ dose measurements using an adult anthropomorphic phantom and risk estimation of cancer incidence from CBCT exposures. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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