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Dufreneix S, Kirié C, Autret D. Evaluation of stereotactic VMAT lung treatment plans for small moving targets. Phys Med 2023; 107:102547. [PMID: 36804692 DOI: 10.1016/j.ejmp.2023.102547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/09/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
PURPOSE The aim of this study is to perform patient quality controls and end-to-end tests for stereotactic VMAT lung treatment plans and to investigate the influence of various parameters on the results. METHOD 18 plans were defined by an experimental design methodology to cover a large variety of stereotactic VMAT lung treatments including different doses per fraction, target diameters, target movements and respiratory parameters. Plans were first controlled using portal dosimetry and a homogeneous static cylindrical phantom. End-to-end tests were then performed in a dynamic respiratory thorax phantom. Measurements were conducted with ionization chamber and films. Calculations were performed with the AcurosXB and AAA algorithms in 6 FFF. RESULTS Portal dosimetry gave excellent gamma pass rates (greater than 97.1 %) and dose deviations between measurement and calculations in a homogeneous static phantom were smaller than 2 %. The methodology followed for comparing calculated and measured doses in a moving target was validated in static fields (largest deviation smaller than 2 %). End-to-end tests showed mean deviations of 1.9 %, 3.3 % and 6.6 % for the 3, 2 and 1 cm diameter's target respectively. Deviations increased for larger movements for the 1 cm lesion. CONCLUSION End-to-end tests revealed that stereotactic VMAT lung treatment plans for moving targets can be delivered within 5 % for 3 and 2 cm diameter targets and amplitudes up to 1.5 cm. The AcurosXB and AAA algorithms however tend to underestimate the dose to the target. Even with satisfactory patient quality controls like portal dosimetry, extra care should be taken for GTV lesions smaller than 2 cm.
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Affiliation(s)
- S Dufreneix
- Institut de Cancérologie de l'Ouest, Angers, France; CEA, List, Laboratoire National Henri Becquerel (LNE-LNHB), Palaiseau, France.
| | - C Kirié
- Institut de Cancérologie de l'Ouest, Angers, France
| | - D Autret
- Institut de Cancérologie de l'Ouest, Angers, France
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Byrne M, Archibald-Heeren B, Hu Y, Greer P, Luo S, Aland T. Assessment of semi-automated stereotactic treatment planning for online adaptive radiotherapy in ethos. Med Dosim 2022; 47:342-347. [PMID: 36127189 DOI: 10.1016/j.meddos.2022.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/04/2022] [Accepted: 08/22/2022] [Indexed: 10/14/2022]
Abstract
INTRODUCTION The Ethos treatment planning system allows for the rapid generation of online adaptive treatment plans while the patient is on the treatment couch. One promising application of online adaptive radiotherapy is its use in stereotactic radiotherapy. The purpose of this study was to ensure the Ethos treatment planning system (TPS) can produce clinically acceptable stereotactic plans, that are non-inferior to those from the Eclipse TPS. METHOD Forty patients that received previous stereotactic radiotherapy treatment on a Halcyon, 20 of which were lung cases, and 20 that were brain cases, were replanned using the Ethos TPS. The generated IMRT and VMAT plans were compared to the clinical Eclipse VMAT plan. RESULTS This study found that the Ethos TPS can produce VMAT plans of equivalent quality (target coverage, conformity and OAR doses) to those from the Eclipse TPS for lung SBRT and brain SRT. The IMRT plans produced by the Ethos planning system were marginally inferior to Eclipse VMAT plans, with the differences likely primarily due to beam geometry rather than the optimization system. Ethos plans were generally more modulated than Eclipse plans. With careful selection of optimization structures and reduction in the body contour, VMAT plan generation time could be reduced by 87%. CONCLUSION Ethos can generate stereotactic VMAT plans that are equivalent to those from Eclipse in the timeframe required for online adaptive radiotherapy.
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Affiliation(s)
- Mikel Byrne
- Strategic Investment & Clinical Care, Icon Group, South Brisbane, QLD, Australia; University of Newcastle, Newcastle, NSW, Australia.
| | - Ben Archibald-Heeren
- Strategic Investment & Clinical Care, Icon Group, South Brisbane, QLD, Australia
| | - Yunfei Hu
- Strategic Investment & Clinical Care, Icon Group, South Brisbane, QLD, Australia
| | - Peter Greer
- University of Newcastle, Newcastle, NSW, Australia; Calvary Mater Newcastle Hospital, Newcastle, NSW, Australia
| | - Suhuai Luo
- University of Newcastle, Newcastle, NSW, Australia
| | - Trent Aland
- Strategic Investment & Clinical Care, Icon Group, South Brisbane, QLD, Australia
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Hu Y, Arnesen M, Aland T. Characterization of an advanced cone beam CT (CBCT) reconstruction algorithm used for dose calculation on Varian Halcyon linear accelerators. Biomed Phys Eng Express 2022; 8. [PMID: 35139503 DOI: 10.1088/2057-1976/ac536b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/09/2022] [Indexed: 11/12/2022]
Abstract
In this study, the performance of a new iterative reconstruction algorithm, the pre-clinical AcurosXB iCBCT algorithm, has been characterized on Varian Halcyon linear accelerators with respect to the potential of radiotherapy dose calculations on CBCT images. The study utilized various phantom setups to verify the accuracy of the pre-clinical algorithm under different scatter conditions and compared dose calculations performed on CBCT images reconstructed with the pre-clinical algorithm to those performed on typical planning CT images. The results indicated that despite showing improvements compared to the existing iCBCT protocol, certain restrictions should be introduced when the pre-clinical AcurosXB iCBCT algorithm was used for dose calculations. Changes in the scatter condition exhibited a larger effect on CBCTs than on planning CTs. Therefore, users should be careful in offsetting the patient and positioning the patient's arms if the resultant images will be used for dose calculations. In addition, protocols with different kV settings should be approached with caution, where 100 kV protocols should only be used to scan the head and neck area, while the rest of the body should be scanned with the 125 kV and 140 kV protocols. When the patient is set up properly and the appropriate energy is selected for the anatomical area, the uncertainty of using the novel AcurosXB iCBCT algorithm for treatment planning dose calculation is within ± 2.0%.
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Affiliation(s)
- Yunfei Hu
- Gosford, Icon Cancer Care South Brisbane, 41 William St, Gosford, New South Wales, 2077, AUSTRALIA
| | - Marius Arnesen
- Toowoomba, Icon Cancer Care South Brisbane, St Andrew's Cancer Care Centre, 280 North St, Rockville, Queensland, 4350, AUSTRALIA
| | - Trent Aland
- National Head Office, Icon Cancer Care South Brisbane, Level 1/22 Cordelia St, South Brisbane, Queensland, 4101, AUSTRALIA
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Miura H. [5. Robust Techniques for Radiotherapy Treatment Plan]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2022; 78:882-888. [PMID: 35989258 DOI: 10.6009/jjrt.2022-2072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
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Savanović M, Jaroš D, Foulquier JN. Planning target volume density impact on treatment planning for lung stereotactic body radiation therapy. Acta Oncol 2021; 60:1296-1300. [PMID: 34259116 DOI: 10.1080/0284186x.2021.1950926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND To evaluate the impact of the planning target volume (PTV) density on treatment planning for lung Stereotactic Body Radiation Therapy (SBRT). MATERIAL AND METHODS The PTV coverage was analyzed in two groups of 40 lung SBRT patients. One group had PTV density <0.5 g/cm3, while the other group had PTV density >0.5 g/cm3. The treatments were planned in Pinnacle 9.10, using the collapsed cone convolution (CCC) algorithm. The prescribed dose was 60 Gy to the PTV in 4-8 fractions. Respecting constraint for the PTV coverage (D98% > 95%), we compared changes in the isodose line prescription, the number of monitor units (MU), maximum dose (Dmax), irradiated volume covered with 30 Gy (V30Gy), and the optimization planning volume (OPV). RESULTS For the same median values of the PTV coverage (98.3%), the differences are presented with median values between lower and higher density than 0.5 g/cm3. The isodose line prescription was 83 vs. 90% (p < 0.0001), the MUs were 2294 vs. 1655 MU (p < 0.0001), Dmax was 74.26 vs. 68.09 Gy (p < 0.0001), V30Gy was 117.03 vs. 104.81 cc (p = 0.04), and OPV was 28.48 vs. 39.35 cc (p < 0.001). By overriding the ITV density to 0.8 g/cm3, the isodose line prescription decreases. The Dmax and MUs decrease by 7%, V30Gy by 34%, and OPV by 70%. CONCLUSION To obtain similar PTV coverage for PTV which is <0.5 g/cm3, a larger margin irradiating a large OPV was used. More MUs and a higher maximum dose were delivered. For the PTV density of ≤0.36 g/cm3, overriding is recommended to reduce the dose and irradiated volume.
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Affiliation(s)
- Milovan Savanović
- Faculty of Medicine, University of Paris-Saclay, Le Kremlin-Bicêtre, France
- Department of Radiation Oncology, Tenon Hospital, APHP, Sorbonne University, Paris, France
| | - Dražan Jaroš
- Center for Radiotherapy, International Medical Centers, Affidea, Banja Luka, Bosnia and Herzegovina
| | - Jean-Noël Foulquier
- Department of Radiation Oncology, Tenon Hospital, APHP, Sorbonne University, Paris, France
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Retif P, Djibo Sidikou A, Letellier R, Verrecchia-Ramos E, Quetin P. Technical Note: A 3D-printed phantom for radiochromic film evaluation of moving lung tumor SBRT without dose convolution. Med Phys 2021; 48:3453-3458. [PMID: 33720419 DOI: 10.1002/mp.14841] [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: 09/02/2020] [Revised: 02/17/2021] [Accepted: 03/03/2021] [Indexed: 12/25/2022] Open
Abstract
PURPOSE A common dosimetric quality assurance (QA) method in stereotactic body radiation therapy (SBRT) of lung tumors is to use lung phantoms with radiochromic film. However, in most phantoms, the film moves with the tumor, leading to the blurring effect. This technical note presents the QA performance of a novel phantom in which the film is fixed; this phantom can be used for both patient-specific QA and end-to-end testing. METHODS Lung tumor motion was simulated with the CIRS Model 008A phantom. A lung-equivalent insert that consisted of a fixed radiochromic film around which a 2-cm tumor moved in the inferior/superior direction (i.e., mimicking respiration-induced tumor motion) was generated by 3D printing. Two common SBRT plans [dynamic conformal arc (DCA) and volumetric-modulated arc therapy (VMAT)] were calculated on the average intensity projection (AIP) image set in Varian Eclipse using the dose calculation algorithm Acuros XB. The plans were delivered by a Varian TrueBeam STx accelerator using 6-MV flattening filter-free energy. EBT3 films were used for treatment-dose verification. The measured and planned dose distributions were compared by using the local gamma index at 3% and 2 mm. RESULTS Mean gamma pass rates of film and planned dose distributions were all ≥95%. DCA and VMAT plans did not differ in gamma pass rates. Planned and measured dose distributions agreed well, as did planned and measured gamma maps. CONCLUSIONS With this new insert, measured and planned dose distributions were very similar, which supports the current view in the field that dose calculations on AIP image sets account sufficiently for tumor motion during treatment. The phantom also performed well despite challenging breathing parameters (large tumor amplitude and slow breathing rate) and the application of a complex treatment technique (VMAT). This phantom could facilitate clinical and end-to-end film-based dosimetric QA for lung SBRT. TAXONOMY Twenty-seven TH- Radiation dose measurement devices. Eleven Phantoms for dosimetric measurement.
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Affiliation(s)
- Paul Retif
- Medical Physics Unit, CHR Metz-Thionville, Metz, France.,Université de Lorraine, CNRS, CRAN, F-54000, Nancy, France
| | | | | | | | - Philippe Quetin
- Radiation Therapy Department, CHR Metz-Thionville, Metz, France
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Image-guided Radiotherapy to Manage Respiratory Motion: Lung and Liver. Clin Oncol (R Coll Radiol) 2020; 32:792-804. [PMID: 33036840 DOI: 10.1016/j.clon.2020.09.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/26/2020] [Accepted: 09/18/2020] [Indexed: 12/25/2022]
Abstract
Organ motion as a result of respiratory and cardiac motion poses significant challenges for the accurate delivery of radiotherapy to both the thorax and the upper abdomen. Modern imaging techniques during radiotherapy simulation and delivery now permit better quantification of organ motion, which in turn reduces tumour and organ at risk position uncertainty. These imaging advances, coupled with respiratory correlated radiotherapy delivery techniques, have led to the development of a range of approaches to manage respiratory motion. This review summarises the key strategies of image-guided respiratory motion management with a focus on lung and liver radiotherapy.
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Miura H, Ozawa S, Doi Y, Nakao M, Kubo K, Kenjo M, Nagata Y. Effectiveness of robust optimization in volumetric modulated arc therapy using 6 and 10 MV flattening filter-free beam therapy planning for lung stereotactic body radiation therapy with a breath-hold technique. JOURNAL OF RADIATION RESEARCH 2020; 61:575-585. [PMID: 32367109 PMCID: PMC7336549 DOI: 10.1093/jrr/rraa026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/27/2020] [Indexed: 06/11/2023]
Abstract
We investigated the feasibility of a robust optimization with 6 MV X-ray (6X) and 10 MV X-ray (10X) flattening filter-free (FFF) beams in a volumetric modulated arc therapy (VMAT) plan for lung stereotactic body radiation therapy (SBRT) using a breath-holding technique. Ten lung cancer patients were selected. Four VMAT plans were generated for each patient; namely, an optimized plan based on the planning target volume (PTV) margin and a second plan based on a robust optimization of the internal target volume (ITV) with setup uncertainties, each for the 6X- and 10X-FFF beams. Both optimized plans were normalized by the percentage of the prescription dose covering 95% of the target volume (D95%) to the PTV (1050 cGy × 4 fractions). All optimized plans were evaluated using perturbed doses by specifying user-defined shifted values from the isocentre. The average perturbed D99% doses to the ITV, compared to the nominal plan, decreased by 369.1 (6X-FFF) and 301.0 cGy (10X-FFF) for the PTV-based optimized plan, and 346.0 (6X-FFF) and 271.6 cGy (10X-FFF) for the robust optimized plan, respectively. The standard deviation of the D99% dose to the ITV were 163.6 (6X-FFF) and 158.9 cGy (10X-FFF) for the PTV-based plan, and 138.9 (6X-FFF) and 128.5 cGy (10X-FFF) for the robust optimized plan, respectively. Robust optimized plans with 10X-FFF beams is a feasible method to achieve dose certainty for the ITV for lung SBRT using a breath-holding technique.
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Affiliation(s)
- Hideharu Miura
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Shuichi Ozawa
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Yoshiko Doi
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Minoru Nakao
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | | | - Masahiko Kenjo
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Yasushi Nagata
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
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Sande EPS, Acosta Roa AM, Hellebust TP. Dose deviations induced by respiratory motion for radiotherapy of lung tumors: Impact of CT reconstruction, plan complexity, and fraction size. J Appl Clin Med Phys 2020; 21:68-79. [PMID: 32166850 PMCID: PMC7170288 DOI: 10.1002/acm2.12847] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 02/03/2020] [Accepted: 02/08/2020] [Indexed: 11/11/2022] Open
Abstract
A thorax phantom was used to assess radiotherapy dose deviations induced by respiratory motion of the target volume. Both intensity modulated and static, non‐modulated treatment plans were planned on CT scans of the phantom. The plans were optimized using various CT reconstructions, to investigate whether they had an impact on robustness to target motion during delivery. During irradiation, the target was programmed to simulate respiration‐induced motion of a lung tumor, using both patient‐specific and sinusoidal motion patterns in three dimensions. Dose was measured in the center of the target using an ion chamber. Differences between reference measurements with a stationary target and dynamic measurements were assessed. Possible correlations between plan complexity metrics and measured dose deviations were investigated. The maximum observed motion‐induced dose differences were 7.8% and 4.5% for single 2 Gy and 15 Gy fractions, respectively. The measurements performed with the largest target motion amplitude in the superior–inferior direction yielded the largest dosimetric deviations. For 2 Gy fractionation schemes, the summed dose deviation after 33 fractions is likely to be less than 2%. Measured motion‐induced dose deviations were significantly larger for one CT reconstruction compared to all the others. Static, non‐modulated plans showed superior robustness to target motion during delivery. Moderate correlations between the modulation complexity score applied to VMAT (MCSv) and measured dose deviations were found for 15 Gy SBRT treatment plans. Correlations between other plan complexity metrics and measured dose deviations were not found.
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Affiliation(s)
- Erlend P S Sande
- Department of Medical Physics, Oslo University Hospital, Oslo, Norway
| | - Ana M Acosta Roa
- Department of Medical Physics, Oslo University Hospital, Oslo, Norway
| | - Taran P Hellebust
- Department of Medical Physics, Oslo University Hospital, Oslo, Norway.,Department of Physics, University of Oslo, Oslo, Norway
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Freislederer P, von Münchow A, Kamp F, Heinz C, Gerum S, Corradini S, Söhn M, Reiner M, Roeder F, Floca R, Alber M, Belka C, Parodi K. Comparison of planned dose on different CT image sets to four-dimensional Monte Carlo dose recalculation using the patient's actual breathing trace for lung stereotactic body radiation therapy. Med Phys 2019; 46:3268-3277. [PMID: 31074510 DOI: 10.1002/mp.13579] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 12/25/2022] Open
Abstract
PURPOSE The need for four-dimensional (4D) treatment planning becomes indispensable when it comes to radiation therapy for moving tumors in the thoracic and abdominal regions. The primary purpose of this study is to combine the actual breathing trace during each individual treatment fraction with the Linac's log file information and Monte Carlo 4D dose calculations. We investigated this workflow on multiple computed tomography (CT) datasets in a clinical environment for stereotactic body radiation therapy (SBRT) treatment planning. METHODS We have developed a workflow, which allows us to recalculate absorbed dose to a 4DCT dataset using Monte Carlo calculation methods and accumulate all 4D doses in order to compare them to the planned dose using the Linac's log file, a 4DCT dataset, and the patient's actual breathing curve for each individual fraction. For five lung patients, three-dimensional-conformal radiation therapy (3D-CRT) and volumetric modulated arc treatment (VMAT) treatment plans were generated on four different CT image datasets: a native free-breathing 3DCT, an average intensity projection (AIP) and a maximum intensity projection (MIP) CT both obtained from a 4DCT, and a 3DCT with density overrides based on the 3DCT (DO). The Monte Carlo 4D dose has been calculated on each 4DCT phase using the Linac's log file and the patient's breathing trace as a surrogate for tumor motion and dose was accumulated to the gross tumor volume (GTV) at the 50% breathing phase (end of exhale) using deformable image registration. RESULTS Δ D 98 % and Δ D 2 % between 4D dose and planned dose differed largely for 3DCT-based planning and also for DO in three patients. Least dose differences between planned and recalculated dose have been found for AIP and MIP treatment planning which both tend to be superior to DO, but the results indicate a dependency on the breathing variability, tumor motion, and size. An interplay effect has not been observed in the small patient cohort. CONCLUSIONS We have developed a workflow which, to our best knowledge, is the first incorporation of the patient breathing trace over the course of all individual treatment fractions with the Linac's log file information and 4D Monte Carlo recalculations of the actual treated dose. Due to the small patient cohort, no clear recommendation on which CT can be used for SBRT treatment planning can be given, but the developed workflow, after adaption for clinical use, could be used to enhance a priori 4D Monte Carlo treatment planning in the future and help with the decision on which CT dataset treatment planning should be carried out.
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Affiliation(s)
- Philipp Freislederer
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Asmus von Münchow
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Florian Kamp
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Christian Heinz
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Sabine Gerum
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Stefanie Corradini
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Matthias Söhn
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Michael Reiner
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | - Falk Roeder
- Department of Radiotherapy and Radiation Oncology, Paracelsus Medical University, Landeskrankenhaus, Salzburg, Austria.,CCU Molecular Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ralf Floca
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany.,Division of Medical Image Computing, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Markus Alber
- Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany.,Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Claus Belka
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany.,German Cancer Consortium (DKTK), Munich, Germany.,Member of the German Center for Lung Research (DZL), Comprehensive Pneumology Center Munich (CPC-M), Munich, Germany
| | - Katia Parodi
- Department of Experimental Physics - Medical Physics, LMU Munich, Munich, Germany
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Pallotta S, Calusi S, Masi L, Talamonti C, Marrazzo L, Foggi L, Casati M, Livi L, Simontacchi G, Desideri I, Lisci R. ADAM phantom to test 4D medical imaging and dose delivery devices. ACTA ACUST UNITED AC 2019; 64:105002. [DOI: 10.1088/1361-6560/ab1a49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Investigating the impact of tumour motion on TomoTherapy stereotactic ablative body radiotherapy (SABR) deliveries on 3-dimensional and 4-dimensional computed tomography. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:169-179. [PMID: 30790140 DOI: 10.1007/s13246-019-00727-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 01/18/2019] [Indexed: 12/25/2022]
Abstract
TomoTherapy can provide highly accurate SABR deliveries, but currently it does not have any effective motion management techniques. Shallow breathing has been identified as one possible motion management solution on TomoTherapy, which has been made possible with the BreatheWell audiovisual biofeedback (AVB) device. Since both the shallow breathing technique and the clinical use of the BreatheWell device are novel, their implementation requires comprehensive verification and validation work. As the first stage of the validation, this paper investigates the impact of target motion on a TomoTherapy SABR delivery is assessed on both 3D CT and 4D CT using a 4D respiratory phantom. A dosimetric study on a 4D respiratory phantom was conducted, with the phantom's insert designed to move at four different amplitudes in the superior-inferior direction. SABR plans on 3D and 4D CT scans were created and measured. Critical plan statistics and measurement results were compared. It is found that for TomoTherapy SABR deliveries, by reducing the targets respiratory motion, target coverage, organ-at-risk (OAR) sparing, and delivery accuracy were improved.
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Schrenk O, Spindeldreier CK, Schmitt D, Roeder F, Bangert M, Burigo LN, Pfaffenberger A. The effect of density overrides on magnetic resonance-guided radiation therapy planning for lung cancer. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 8:23-27. [PMID: 33458412 PMCID: PMC7807559 DOI: 10.1016/j.phro.2018.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 12/31/2022]
Abstract
Background and Purpose Inverse treatment planning for lung cancer can be challenging since density heterogeneities may appear inside the planning target volume (PTV). One method to improve the quality of intensity modulation is the override of low density tissues inside the PTV during plan optimization. For magnetic resonance-guided radiation therapy (MRgRT), where the influence of the magnetic field on secondary electrons is sensitive to the tissue density, the reliability of density overrides has not yet been proven. This work, therefore, gains a first insight into density override strategies for MRgRT. Material and methods Monte Carlo-based treatment plans for five lung cancer patients were generated based on free-breathing CTs and two density override strategies. Different magnetic field configurations were considered with their effect being accounted for during optimization. Optimized plans were forward calculated to 4D-CTs and accumulated for the comparison of planned and expected delivered dose. Results For MRgRT, density overrides led to a discrepancy between the delivered and planned dose. The tumor volume coverage deteriorated for perpendicular magnetic fields of 1.5 T to 93.6% (D98%). For inline fields a maximal increase of 2.2% was found for the mean dose. In terms of organs at risk, a maximal sparing of 0.6 Gy and 0.9 Gy was observed for lung and heart, respectively. Conclusions In this work, first results on the effect of density overrides on treatment planning for MRgRT are presented. It was observed that the underestimation of magnetic field effects in overridden densities during treatment planning resulted in an altered delivered dose, depending on the field strength and orientation.
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Affiliation(s)
- Oliver Schrenk
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Medical Faculty, University of Heidelberg, Heidelberg, Germany
| | - Claudia Katharina Spindeldreier
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Daniela Schmitt
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Falk Roeder
- Clinical Cooperation Unit Molecular Radiooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Radiation Oncology, University of Munich (LMU), Munich, Germany
| | - Mark Bangert
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Lucas Norberto Burigo
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Asja Pfaffenberger
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
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14
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Healy GEA, Marsh SH, Cousins AT. The dosimetric effect of electron density overrides in 3DCRT Lung SBRT for a range of lung tumor dimensions. J Appl Clin Med Phys 2018; 19:79-87. [PMID: 30199127 PMCID: PMC6236830 DOI: 10.1002/acm2.12446] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 07/24/2018] [Accepted: 08/04/2018] [Indexed: 11/25/2022] Open
Abstract
The combined effects of lung tumor motion and limitations of treatment planning system dose calculations in lung regions increases uncertainty in dose delivered to the tumor and surrounding normal tissues in lung stereotactic body radiotherapy (SBRT). This study investigated the effect on plan quality and accuracy when overriding treatment volume electron density values. The QUASAR phantom with modified cork cylindrical inserts, each containing a simulated spherical tumor of 15‐mm, 22‐mm, or 30‐mm diameter, was used to simulate lung tumor motion. Using Monaco 5.1 treatment planning software, two standard plans (50% central phase (50%) and average intensity projection (AIP)) were compared to eight electron density overridden plans that focused on different target volumes (internal target volume (ITV), planning target volume (PTV), and a hybrid plan (HPTV)). The target volumes were set to a variety of electron densities between lung and water equivalence. Minimal differences were seen in the 30‐mm tumor in terms of target coverage, plan conformity, and improved dosimetric accuracy. For the smaller tumors, a PTV override showed improved target coverage as well as better plan conformity compared to the baseline plans. The ITV plans showed the highest gamma pass rate agreement between treatment planning system (TPS) and measured dose (P < 0.040). However, the low electron density PTV and HPTV plans also showed improved gamma pass rates (P < 0.035, P < 0.011). Low‐density PTV overrides improved the plan quality and accuracy for tumor diameters less than 22 mm only. Although an ITV override generated the most significant increase in accuracy, the low‐density PTV plans had the additional benefit of plan quality improvement. Although this study and others agreed that density overrides improve the treatment of SBRT, the optimal density override and the conditions under which it should be applied were found to be department specific, due to variations in commissioning and calculation methods.
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Affiliation(s)
- Grace E A Healy
- University of Canterbury, Canterbury, New Zealand.,Department of Medical Physics and Bioengineering, Christchurch Hospital, Canterbury, New Zealand
| | | | - Andrew T Cousins
- Department of Medical Physics and Bioengineering, Christchurch Hospital, Canterbury, New Zealand
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15
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Mohatt DJ, Ma T, Wiant DB, Islam NM, Gomez J, Singh AK, Malhotra HK. Technical and dosimetric implications of respiratory induced density variations in a heterogeneous lung phantom. Radiat Oncol 2018; 13:165. [PMID: 30180894 PMCID: PMC6124019 DOI: 10.1186/s13014-018-1110-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/21/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Stereotactic Body Radiotherapy (SBRT) is an ablative dose delivery technique which requires the highest levels of precision and accuracy. Modeling dose to a lung treatment volume has remained a complex and challenging endeavor due to target motion and the low density of the surrounding media. When coupled together, these factors give rise to pulmonary induced tissue heterogeneities which can lead to inaccuracies in dose computation. This investigation aims to determine which combination of imaging techniques and computational algorithms best compensates for time dependent lung target displacements. METHODS A Quasar phantom was employed to simulate respiratory motion for target ranges up to 3 cm. 4DCT imaging was used to generate Average Intensity Projection (AIP), Free Breathing (FB), and Maximum Intensity Projection (MIP) image sets. In addition, we introduce and compare a fourth dataset for dose computation based on a novel phase weighted density (PWD) technique. All plans were created using Eclipse version 13.6 treatment planning system and calculated using the Analytical Anisotropic Algorithm and Acuros XB. Dose delivery was performed using Truebeam STx linear accelerator where radiochromic film measurements were accessed using gamma analysis to compare planned versus delivered dose. RESULTS In the most extreme case scenario, the mean CT difference between FB and MIP datasets was found to be greater than 200 HU. The near maximum dose discrepancies between AAA and AXB algorithms were determined to be marginal (< 2.2%), with a greater variability occurring within the near minimum dose regime (< 7%). Radiochromatic film verification demonstrated all AIP and FB based computations exceeded 98% passing rates under conventional radiotherapy tolerances (gamma 3%, 3 mm). Under more stringent SBRT tolerances (gamma 3%, 1 mm), the AIP and FB based treatment plans exhibited higher pass rates (> 85%) when compared to MIP and PWD (< 85%) for AAA computations. For AXB, however, the delivery accuracy for all datasets were greater than 85% (gamma 3%,1 mm), with a corresponding reduction in overall lung irradiation. CONCLUSIONS Despite the substantial density variations between computational datasets over an extensive range of target movement, the dose difference between CT datasets is small and could not be quantified with ion chamber. Radiochromatic film analysis suggests the optimal CT dataset is dependent on the dose algorithm used for evaluation. With AAA, AIP and FB resulted in the best conformance between measured versus calculated dose for target motion ranging up to 3 cm under both conventional and SBRT tolerance criteria. With AXB, pass rates improved for all datasets with the PWD technique demonstrating slightly better conformity over AIP and FB based computations (gamma 3%, 1 mm). As verified in previous studies, our results confirm a clear advantage in delivery accuracy along with a relative decrease in calculated dose to the lung when using Acuros XB over AAA.
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Affiliation(s)
- Dennis J Mohatt
- Medical Physics Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14214-3005, USA. .,Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, 14293, USA.
| | - Tianjun Ma
- Medical Physics Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14214-3005, USA.,Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, 14293, USA
| | - David B Wiant
- Radiation Oncology, Cone Health Cancer Center, Greensboro, NC, 27403, USA
| | - Naveed M Islam
- Medical Physics Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14214-3005, USA.,Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, 14293, USA
| | - Jorge Gomez
- Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, 14293, USA
| | - Anurag K Singh
- Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, 14293, USA
| | - Harish K Malhotra
- Medical Physics Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14214-3005, USA.,Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY, 14293, USA
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16
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Liang X, Zheng D, Mamalui-Hunter M, Flampouri S, Hoppe BS, Mendenhall N, Li Z. ITV-Based Robust Optimization for VMAT Planning of Stereotactic Body Radiation Therapy of Lung Cancer. Pract Radiat Oncol 2018; 9:38-48. [PMID: 30138747 DOI: 10.1016/j.prro.2018.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 07/09/2018] [Accepted: 08/09/2018] [Indexed: 12/11/2022]
Abstract
PURPOSE Using planning target volume (PTV) to account for setup uncertainties in stereotactic body radiation therapy (SBRT) of lung cancer has been questioned because a significant portion of the PTV contains low-density lung tissue. The purpose of this study is to (1) investigate the feasibility of using robust optimization to account for setup uncertainties in volumetric modulated arc therapy plan for lung SBRT and (2) evaluate the potential normal tissue-sparing benefit of a robust optimized plan compared with a conventional PTV-based optimized plan. METHODS AND MATERIALS The study was conducted with both phantom and patient cases. For each patient or phantom, 2 SBRT lung volumetric modulated arc therapy plans were generated, including an optimized plan based on the PTV (PTV-based plan) with a 5-mm internal target volume (ITV)-to-PTV margin and a second plan based on robust optimization of ITV (ITV-based plan) with ±5-mm setup uncertainties. The target coverage was evaluated on ITV D99 in 15 scenarios that simulated a 5-mm setup error. Dose-volume information on normal lung tissue, intermediate-to-high dose spillage, and integral dose was evaluated. RESULTS Compared with PTV-based plans, ITV-based robust optimized plans resulted in lower normal lung tissue dose, lower intermediate-to-high dose spillage to the body, and lower integral dose, while preserving the dose coverage under setup error scenarios for both phantom and patient cases. CONCLUSIONS Using ITV-based robust optimization, we have shown that accounting for setup uncertainty in SBRT planning is feasible. Further clinical studies are warranted to confirm the clinical effectiveness of this novel approach.
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Affiliation(s)
- Xiaoying Liang
- Department of Radiation Oncology, University of Florida, Gainesville, Florida.
| | - Dandan Zheng
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, Nebraska
| | | | - Stella Flampouri
- Department of Radiation Oncology, University of Florida, Gainesville, Florida
| | - Bradford S Hoppe
- Department of Radiation Oncology, University of Florida, Gainesville, Florida
| | - Nancy Mendenhall
- Department of Radiation Oncology, University of Florida, Gainesville, Florida
| | - Zuofeng Li
- Department of Radiation Oncology, University of Florida, Gainesville, Florida
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17
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Archibald-Heeren BR, Byrne MV, Hu Y, Cai M, Wang Y. Robust optimization of VMAT for lung cancer: Dosimetric implications of motion compensation techniques. J Appl Clin Med Phys 2017; 18:104-116. [PMID: 28786213 PMCID: PMC5874938 DOI: 10.1002/acm2.12142] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/01/2017] [Accepted: 06/02/2017] [Indexed: 12/25/2022] Open
Abstract
In inverse planning of lung radiotherapy, techniques are required to ensure dose coverage of target disease in the presence of tumor motion as a result of respiration. A range of published techniques for mitigating motion effects were compared for dose stability across 5 breath cycles of ±2 cm. Techniques included planning target volume (PTV) expansions, internal target volumes with (OITV) and without tissue override (ITV), average dataset scans (ADS), and mini-max robust optimization. Volumetric arc therapy plans were created on a thorax phantom and verified with chamber and film measurements. Dose stability was compared by DVH analysis in calculations across all geometries. The lung override technique resulted in a substantial lack of dose coverage (-10%) to the tumor in the presence of large motion. PTV, ITV and ADS techniques resulted in substantial (up to 25%) maximum dose increases where solid tissue travelled into low density optimized regions. The results highlight the need for care in optimization of highly heterogeneous where density variations may occur with motion. Robust optimization was shown to provide greater stability in both maximum (<3%) and minimum dose variations (<2%) over all other techniques.
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Affiliation(s)
- Ben R Archibald-Heeren
- Radiation Oncology Centre, Sydney Adventist Hospital, Sydney, NSW, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
| | - Mikel V Byrne
- Radiation Oncology Centre, Sydney Adventist Hospital, Sydney, NSW, Australia
| | - Yunfei Hu
- Radiation Oncology Centre, Sydney Adventist Hospital, Sydney, NSW, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
| | - Meng Cai
- Radiation Oncology Centre, Sydney Adventist Hospital, Sydney, NSW, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
| | - Yang Wang
- Radiation Oncology Centre, Sydney Adventist Hospital, Sydney, NSW, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
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18
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Brandner ED, Chetty IJ, Giaddui TG, Xiao Y, Huq MS. Motion management strategies and technical issues associated with stereotactic body radiotherapy of thoracic and upper abdominal tumors: A review from NRG oncology. Med Phys 2017; 44:2595-2612. [PMID: 28317123 DOI: 10.1002/mp.12227] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/23/2017] [Accepted: 03/10/2017] [Indexed: 12/11/2022] Open
Abstract
The efficacy of stereotactic body radiotherapy (SBRT) has been well demonstrated. However, it presents unique challenges for accurate planning and delivery especially in the lungs and upper abdomen where respiratory motion can be significantly confounding accurate targeting and avoidance of normal tissues. In this paper, we review the current literature on SBRT for lung and upper abdominal tumors with particular emphasis on addressing respiratory motion and its affects. We provide recommendations on strategies to manage motion for different, patient-specific situations. Some of the recommendations will potentially be adopted to guide clinical trial protocols.
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Affiliation(s)
- Edward D Brandner
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute and UPMC CancerCenter, Pittsburgh, PA, 15232, USA
| | - Indrin J Chetty
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, 48202, USA
| | - Tawfik G Giaddui
- Sidney Kimmel Cancer Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Ying Xiao
- Imaging and Radiation Oncology Core (IROC), University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - M Saiful Huq
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute and UPMC CancerCenter, Pittsburgh, PA, 15232, USA
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19
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Schwarz M, Cattaneo GM, Marrazzo L. Geometrical and dosimetrical uncertainties in hypofractionated radiotherapy of the lung: A review. Phys Med 2017; 36:126-139. [DOI: 10.1016/j.ejmp.2017.02.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/23/2016] [Accepted: 02/14/2017] [Indexed: 12/25/2022] Open
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20
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Ohira S, Ueda Y, Hashimoto M, Miyazaki M, Isono M, Kamikaseda H, Masaoka A, Takashina M, Koizumi M, Teshima T. VMAT-SBRT planning based on an average intensity projection for lung tumors located in close proximity to the diaphragm: a phantom and clinical validity study. JOURNAL OF RADIATION RESEARCH 2016; 57:91-97. [PMID: 26419645 PMCID: PMC4708914 DOI: 10.1093/jrr/rrv058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/05/2015] [Accepted: 08/21/2015] [Indexed: 06/05/2023]
Abstract
The aim of the this study was to validate the use of an average intensity projection (AIP) for volumetric-modulated arc therapy for stereotactic body radiation therapy (VMAT-SBRT) planning for a moving lung tumor located near the diaphragm. VMAT-SBRT plans were created using AIPs reconstructed from 10 phases of 4DCT images that were acquired with a target phantom moving with amplitudes of 5, 10, 20 and 30 mm. To generate a 4D dose distribution, the static dose for each phase was recalculated and the doses were accumulated by using the phantom position known for each phase. For 10 patients with lung tumors, a deformable registration was used to generate 4D dose distributions. Doses to the target volume obtained from the AIP plan and the 4D plan were compared, as were the doses obtained from each plan to the organs at risk (OARs). In both phantom and clinical study, dose discrepancies for all parameters of the dose volume (D(min), D(99), D(max), D(1) and D(mean)) to the target were <3%. The discrepancies of D(max) for spinal cord, esophagus and heart were <1 Gy, and the discrepancy of V20 for lung tissue was <1%. However, for OARs with large respiratory motion, the discrepancy of the D(max) was as much as 9.6 Gy for liver and 5.7 Gy for stomach. Thus, AIP is clinically acceptable as a planning CT image for predicting 4D dose, but doses to the OARs with large respiratory motion were underestimated with the AIP approach.
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Affiliation(s)
- Shingo Ohira
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Misaki Hashimoto
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masayoshi Miyazaki
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Masaru Isono
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Hiroshi Kamikaseda
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Akira Masaoka
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Masaaki Takashina
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Teruki Teshima
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
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