1
|
Potter S, Maxwell C, Rijken J. The accuracy of Eclipse AXB and AAA dose algorithms with dental amalgam. Phys Eng Sci Med 2024:10.1007/s13246-024-01471-4. [PMID: 39141184 DOI: 10.1007/s13246-024-01471-4] [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: 02/04/2024] [Accepted: 07/28/2024] [Indexed: 08/15/2024]
Abstract
High-density materials used for dental restorations are poorly defined in CT imaging due to scanner limitations. Studies have established that Eclipse offers poor agreement with delivered dose in situations involving high-density material. Defining the accuracy of dose algorithms in situations involving high-density overrides would improve clinical outcomes both for target coverage and OAR sparing. Dental amalgam was placed within a solid water phantom and measurements were taken at 1 cm increments beneath the amalgam down to a depth of 6 cm. Exposed film was compared with Eclipse Treatment Planning system (TPS) calculations on a CT of the experimental setup. The amalgam was overridden with a range of HU values and material selections for dose calculation. AXB performs poorly at describing depth dose downstream of Amalgam, regardless of the override material selected. Applying the known mass density with the Anisotropic Analytical Algorithm (AAA) predicts an average of 1.8% and 2.8% for 6 MV and 10 MV beams. The closest agreement achieved using the Acuros XB (AXB) was overriding with stainless steel, which predicted approximately 1.1% and 1.8% above measured dose for 6 MV and 10 MV respectively. Without overriding the density of amalgam, AAA and AXB return depth dose predictions of 7.3% and 5.8% above film measurement for a 6 MV and 7.6% and 6.5% for 10 MV static beams. Applying override options to a clinical case using an anthropomorphic phantom showed using AXB with Stainless Steel as amalgam override returns the same results as AAA with mass density applied for amalgam. Both of these were in close agreement to the TPS.
Collapse
Affiliation(s)
- Sam Potter
- Icon Cancer Centre, Windsor Gardens, SA, Australia.
| | | | - James Rijken
- Icon Cancer Centre, Windsor Gardens, SA, Australia
| |
Collapse
|
2
|
Malhotra A, Carpentier EE, Duzenli C. Recommendations for using analytical anisotropic algorithm and AcurosXB for epidermal dose calculations in breast radiotherapy from an in vivo Gafchromic film study. J Appl Clin Med Phys 2024; 25:e14416. [PMID: 38812120 PMCID: PMC11302804 DOI: 10.1002/acm2.14416] [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: 02/12/2024] [Revised: 03/27/2024] [Accepted: 04/25/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND AND PURPOSE This study recommends clinical epidermal dose calculation methods based on in-vivo film measurements and registered skin dose distributions with the Eclipse (Varian Medical Systems) treatment planning system's Analytical Anisotropic Algorithm (AAA) and Acuros XB (AXB) dose calculation algorithms. MATERIALS AND METHODS Eighteen AAA V13.6 breast plans were recalculated using AXB (dose to medium) V13.5 with the same beam parameters and monitor units as in the original plans. These are compared against in-vivo Gafchromic film measurements from the lateral and inferior breast regions. Three skin structures in the treatment planning system are evaluated: a surface layer of voxels of the body contour, a 0.2 cm internal skin rind, and a 0.5 cm internal skin rind. RESULTS Systematic shifts are demonstrated between the film measurements of skin dose and the Eclipse dose calculations. On average, the dose to the surface layer of pixels is underestimated by AAA by 8% and overestimated by AXB by 3%. A 5 mm skin rind extended into the body can increase epidermal dose calculations on average by 8% for AAA and 4% for AXB. CONCLUSION This is the first study to register in-vivo skin dose distributions in the breast to the treatment planning system for comparison. Based on the results from this study it is recommended that epidermal dose is calculated with a 0.5 cm skin rind for the AAA algorithm and with rind thickness up to 0.2 cm for the AXB algorithm.
Collapse
Affiliation(s)
- Aria Malhotra
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Emilie E. Carpentier
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Cheryl Duzenli
- BC CancerVancouverBritish ColumbiaCanada
- Department of Physics and AstronomyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of SurgeryDivision of Radiation Oncology and Experimental RadiotherapeuticsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| |
Collapse
|
3
|
Schmidt TR, Dwyer RH, Broughton DP, Hochanadel MP, Batha SH. A modular, high dynamic range passive neutron dosimeter and imaging diagnostic. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:073513. [PMID: 39007678 DOI: 10.1063/5.0216486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/01/2024] [Indexed: 07/16/2024]
Abstract
The multi-decade neutron dosimeter and imaging diagnostic (MDND) is a passive diagnostic that utilizes the polyethylene (n, p) nuclear reaction to enhance the diagnostic's sensitivity for time and energy integrated neutron measurements in the range of 2.45-14.1 MeV. The MDND utilizes a combination of radiochromic film, phosphor image plates, and solid-state nuclear track detectors, with the goal of providing several orders of magnitude of dynamic range in terms of measured neutron fluence. The diagnostic design was guided by simulations in the Monte Carlo N-Particle (MCNP) transport code to determine the optimum thickness of the polyethylene convertor for maximum proton fluence incident on the detection medium as a function of incident neutron energy. In addition, the simulation results of complete diagnostic assemblies, or "stacks," were used to determine the total dynamic range of an MDND in terms of measured neutron source yield, which was found to be between around 107 and 1015 emitted into 4π with the detector located 1 m away from the source. Complimentary to these simulations, individual detectors within a stack were simulated and analyzed to determine response as a function of neutron energy and yield. This work presents the diagnostic design, MCNP simulation results, and analysis of expected signals for varying neutron sources.
Collapse
Affiliation(s)
- T R Schmidt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - R H Dwyer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - D P Broughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - M P Hochanadel
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - S H Batha
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| |
Collapse
|
4
|
Diaz-Martinez VD, Cyr M, Devic S, Tomic N, Lewis DF, Enger SA. Investigation of dosimetric characteristics of radiochromic film in response to alpha particles emitted from Americium-241. Med Phys 2024. [PMID: 38767310 DOI: 10.1002/mp.17133] [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: 08/26/2023] [Revised: 02/15/2024] [Accepted: 03/15/2024] [Indexed: 05/22/2024] Open
Abstract
BACKGROUND In radiotherapy, it is essential to deliver prescribed doses to tumors while minimizing damage to surrounding healthy tissue. Accurate measurements of absorbed dose are required for this purpose. Gafchromic® external beam therapy (EBT) radiochromic films have been widely used in radiotherapy. While the dosimetric characteristics of the EBT3 model film have been extensively studied for photon and charged particle beams (protons, electrons, and carbon ions), little research has been done on α $\alpha$ -particle dosimetry. α $\alpha$ -emitting radionuclides have gained popularity in cancer treatment due to their high linear energy transfer, short range in tissue, and ability to spare surrounding organs at risk, thereby delivering a more localized dose distribution to the tumor. Therefore, a dose-calibration film protocol for α $\alpha$ -particles is required. PURPOSE This study aimed to develop a dose-calibration protocol for the α $\alpha$ -particle emitting radionuclide 241Am, using Monte Carlo (MC) simulations and measurements with unlaminated EBT3 films. METHODS In this study, a MC-based user code was developed using the Geant4 simulation toolkit to model and simulate an 241Am source and an unlaminated EBT3 film. Two simulations were performed: one with voxelized geometries of the EBT3 active volume composition and the other using water. The dose rate was calculated within a region of interest in the voxelized geometries. Unlaminated EBT3 film pieces were irradiated with the 241Am source at various exposure times inside a black box. Film irradiations were compared to a 6-MV photon beam from a Varian TrueBeam machine. The simulated dose rate was used to convert the exposure times into absorbed doses to water, describing a radiochromic-film-based reference dosimetry protocol for α $\alpha$ -particles. The irradiated films were scanned and through an in-house Python script, the normalized pixel values from the green-color channel of scanned film images were analyzed. RESULTS The 241Am energy spectra obtained from the simulations were in good agreement with IAEA and NIST databases, having differences < $<$ 0.516% for the emitted γ $\gamma$ -rays and produced characteristic x-rays and < $<$ 0.006% for the α $\alpha$ -particles. Due to the short range of α $\alpha$ -particles, there was no energy deposition in the voxels outside the active 241Am source region projected onto the film surface. Thus, the total dose rate within the voxels covering the source was 0.847 ± $\pm$ 0.003 Gy/min within the sensitive layer of the film (LiPCDA) and 0.847 ± $\pm$ 0.004 Gy/min in water, indicating that the active volume can be considered water equivalent for the 241Am beam quality. A novel approach was employed in α $\alpha$ -film dosimetry using an exponential fit for the green channel, which showed promising results by reducing the uncertainty in dose estimation within 5%. Although the statistical analysis did not reveal significant differences between the 6-MV photon beam and the α $\alpha$ calibration curves, the dose-response curves exhibited the expected behavior. CONCLUSIONS The developed MC user code simulated the experimental setup for α $\alpha$ -dosimetry using radiochromic film with acceptable uncertainty. Unlaminated EBT3 film is suitable for the dosimetry of α $\alpha$ -radiation at low doses and can be used in conjunction with other unlaminated GafChromic® films for quality assurance and research purposes.
Collapse
Affiliation(s)
- Victor D Diaz-Martinez
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Mélodie Cyr
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Slobodan Devic
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Nada Tomic
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | | | - Shirin A Enger
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
- Research Institute of McGill University Health Centre, Montréal, Québec, Canada
| |
Collapse
|
5
|
Prezado Y, Grams M, Jouglar E, Martínez-Rovira I, Ortiz R, Seco J, Chang S. Spatially fractionated radiation therapy: a critical review on current status of clinical and preclinical studies and knowledge gaps. Phys Med Biol 2024; 69:10TR02. [PMID: 38648789 DOI: 10.1088/1361-6560/ad4192] [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: 11/27/2023] [Accepted: 04/22/2024] [Indexed: 04/25/2024]
Abstract
Spatially fractionated radiation therapy (SFRT) is a therapeutic approach with the potential to disrupt the classical paradigms of conventional radiation therapy. The high spatial dose modulation in SFRT activates distinct radiobiological mechanisms which lead to a remarkable increase in normal tissue tolerances. Several decades of clinical use and numerous preclinical experiments suggest that SFRT has the potential to increase the therapeutic index, especially in bulky and radioresistant tumors. To unleash the full potential of SFRT a deeper understanding of the underlying biology and its relationship with the complex dosimetry of SFRT is needed. This review provides a critical analysis of the field, discussing not only the main clinical and preclinical findings but also analyzing the main knowledge gaps in a holistic way.
Collapse
Affiliation(s)
- Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, F-91400, Orsay, France
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, F-91400, Orsay, France
- New Approaches in Radiotherapy Lab, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Instituto de investigación Sanitaria de Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, A Coruña, E-15706, Spain
- Oportunius Program, Galician Agency of Innovation (GAIN), Xunta de Galicia, Santiago de Compostela, A Coruña, Spain
| | - Michael Grams
- Department of Radiation Oncology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, United States of America
| | - Emmanuel Jouglar
- Institut Curie, PSL Research University, Department of Radiation Oncology, F-75005, Paris and Orsay Protontherapy Center, F-91400, Orsay, France
| | - Immaculada Martínez-Rovira
- Physics Department, Universitat Auto`noma de Barcelona, E-08193, Cerdanyola del Valle`s (Barcelona), Spain
| | - Ramon Ortiz
- University of California San Francisco, Department of Radiation Oncology, 1600 Divisadero Street, San Francisco, CA 94143, United States of America
| | - Joao Seco
- Division of Biomedical physics in Radiation Oncology, DKFZ-German Cancer Research Center, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Sha Chang
- Dept of Radiation Oncology and Department of Biomedical Engineering, University of North Carolina School of Medicine, United States of America
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolin State University, United States of America
| |
Collapse
|
6
|
Clements N, Esplen N, Bateman J, Robertson C, Dosanjh M, Korysko P, Farabolini W, Corsini R, Bazalova-Carter M. Mini-GRID radiotherapy on the CLEAR very-high-energy electron beamline: collimator optimization, film dosimetry, and Monte Carlo simulations. Phys Med Biol 2024; 69:055003. [PMID: 38295408 DOI: 10.1088/1361-6560/ad247d] [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: 08/10/2023] [Accepted: 01/31/2024] [Indexed: 02/02/2024]
Abstract
Objective.Spatially-fractionated radiotherapy (SFRT) delivered with a very-high-energy electron (VHEE) beam and a mini-GRID collimator was investigated to achieve synergistic normal tissue-sparing through spatial fractionation and the FLASH effect.Approach.A tungsten mini-GRID collimator for delivering VHEE SFRT was optimized using Monte Carlo (MC) simulations. Peak-to-valley dose ratios (PVDRs), depths of convergence (DoCs, PVDR ≤ 1.1), and peak and valley doses in a water phantom from a simulated 150 MeV VHEE source were evaluated. Collimator thickness, hole width, and septal width were varied to determine an optimal value for each parameter that maximized PVDR and DoC. The optimized collimator (20 mm thick rectangular prism with a 15 mm × 15 mm face with a 7 × 7 array of 0.5 mm holes separated by 1.1 mm septa) was 3D-printed and used for VHEE irradiations with the CERN linear electron accelerator for research beam. Open beam and mini-GRID irradiations were performed at 140, 175, and 200 MeV and dose was recorded with radiochromic films in a water tank. PVDR, central-axis (CAX) and valley dose rates and DoCs were evaluated.Main results.Films demonstrated peak and valley dose rates on the order of 100 s of MGy/s, which could promote FLASH-sparing effects. Across the three energies, PVDRs of 2-4 at 13 mm depth and DoCs between 39 and 47 mm were achieved. Open beam and mini-GRID MC simulations were run to replicate the film results at 200 MeV. For the mini-GRID irradiations, the film CAX dose was on average 15% higher, the film valley dose was 28% higher, and the film PVDR was 15% lower than calculated by MC.Significance.Ultimately, the PVDRs and DoCs were determined to be too low for a significant potential for SFRT tissue-sparing effects to be present, particularly at depth. Further beam delivery optimization and investigations of new means of spatial fractionation are warranted.
Collapse
Affiliation(s)
- Nathan Clements
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | - Nolan Esplen
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | - Joseph Bateman
- Department of Physics, University of Oxford, Oxford, United Kingdom
| | | | - Manjit Dosanjh
- Department of Physics, University of Oxford, Oxford, United Kingdom
- CERN, Geneva, Switzerland
| | - Pierre Korysko
- Department of Physics, University of Oxford, Oxford, United Kingdom
- CERN, Geneva, Switzerland
| | | | | | | |
Collapse
|
7
|
Malhotra A, Carpentier EE, Grahame S, Chan EK, Nichol A, Duzenli C. Toward a Skin Dose-Area Metric Predictive of Moist Desquamation Using In Vivo Skin Dosimetry and Skin Assessments. Adv Radiat Oncol 2024; 9:101318. [PMID: 38260224 PMCID: PMC10801659 DOI: 10.1016/j.adro.2023.101318] [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: 03/26/2023] [Accepted: 07/13/2023] [Indexed: 01/24/2024] Open
Abstract
Purpose Moist desquamation (MD) is a concerning acute side effect of radiation therapy for breast cancer, often seen in skin folds for patients having large or pendulous breasts. In vivo skin dosimetry, clinical assessments, and patient-reported skin reactions were used to determine a relationship between dose-area metrics and the development of MD, to lend insight into skin tolerances and possibly guide future treatment planning dose constraints. Methods and Materials Skin dose was measured using GafChromic film on the inner surface of an early prototype carbon-fiber accessory for breast support to remove the inframammary fold in 20 patients at high risk of developing MD undergoing adjuvant whole breast radiation therapy. Prescribed doses were 42.5 Gray (Gy) in 16 fractions or 50 Gy in 25 fractions using 6 to 15 MV x-rays. To account for fraction size differences, analysis was performed using the equivalent dose in 2 Gy fractions using α/β = 11 (EQD211). MD was assessed out to 2 weeks post radiation therapy by trained therapists and by a patient-reported outcome questionnaire. Results Statistically significant differences in areas receiving 30 to 48 Gy (EQD211) were observed between patients who did and did not develop MD in the inframammary area. Patients receiving EQD211 maximum dose ≤ 46 Gy and ≥ 38 Gy to ≤ 50 cm2 of their breast skin did not develop MD. Conclusions The findings of this study offer insight into the relationship between skin toxicity and areas of skin irradiated to doses up to 50 Gy. Potential skin dose constraints to test in future studies to prevent MD are suggested.
Collapse
Affiliation(s)
- Aria Malhotra
- Department of Medical Physics, BC Cancer, Vancouver, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Emilie E. Carpentier
- Department of Medical Physics, BC Cancer, Vancouver, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Sheri Grahame
- Department of Radiation Therapy, BC Cancer, Vancouver, Canada
| | - Elisa K. Chan
- Department of Radiation Oncology, BC Cancer, Vancouver, Canada
- Department of Surgery, Division of Radiation Oncology and Developmental Radiotherapeutics, University of British Columbia, Vancouver, Canada
| | - Alan Nichol
- Department of Radiation Oncology, BC Cancer, Vancouver, Canada
- Department of Surgery, Division of Radiation Oncology and Developmental Radiotherapeutics, University of British Columbia, Vancouver, Canada
| | - Cheryl Duzenli
- Department of Medical Physics, BC Cancer, Vancouver, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Department of Surgery, Division of Radiation Oncology and Developmental Radiotherapeutics, University of British Columbia, Vancouver, Canada
| |
Collapse
|
8
|
Lin YF, Hsieh CH, Tien HJ, Lee YH, Chen YC, Lai LH, Hsu SM, Shueng PW. Evaluation of cutout factors with small and narrow fields using various dosimetry detectors in electron beam keloid radiotherapy. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2024; 32:1177-1184. [PMID: 38905079 DOI: 10.3233/xst-240059] [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: 06/23/2024]
Abstract
BACKGROUND The inherent problems in the existence of electron equilibrium and steep dose fall-off pose difficulties for small- and narrow-field dosimetry. OBJECTIVE To investigate the cutout factors for keloid electron radiotherapy using various dosimetry detectors for small and narrow fields. METHOD The measurements were performed in a solid water phantom with nine different cutout shapes. Five dosimetry detectors were used in the study: pinpoint 3D ionization chamber, Farmer chamber, semiflex chamber, Classic Markus parallel plate chamber, and EBT3 film. RESULTS The results demonstrated good agreement between the semiflex and pinpoint chambers. Furthermore, there was no difference between the Farmer and pinpoint chambers for large cutouts. For the EBT3 film, half of the cases had differences greater than 1%, and the maximum discrepancy compared with the reference chamber was greater than 2% for the narrow field. CONCLUSION The parallel plate, semiflex chamber and EBT3 film are suitable dosimeters that are comparable with pinpoint 3D chambers in small and narrow electron fields. Notably, a semiflex chamber could be an alternative option to a pinpoint 3D chamber for cutout widths≥3 cm. It is very important to perform patient-specific cutout factor calibration with an appropriate dosimeter for keloid radiotherapy.
Collapse
Affiliation(s)
- Yu-Fang Lin
- Department of Radiology, Division of Radiation Oncology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chen-Hsi Hsieh
- Department of Radiology, Division of Radiation Oncology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Traditional Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- School of Nursing, Yuan Ze University, Taoyuan, Taiwan
| | - Hui-Ju Tien
- Department of Radiology, Division of Radiation Oncology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Huan Lee
- Department of Radiology, Division of Radiation Oncology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Yi-Chun Chen
- Department of Radiology, Division of Radiation Oncology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Lu-Han Lai
- Department of Medical Imaging and Radiological Technology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Shih-Ming Hsu
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Pei-Wei Shueng
- Department of Radiology, Division of Radiation Oncology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| |
Collapse
|
9
|
Guerra Liberal FDC, Parsons JL, McMahon SJ. Most DNA repair defects do not modify the relationship between relative biological effectiveness and linear energy transfer in CRISPR-edited cells. Med Phys 2024; 51:591-600. [PMID: 37753877 DOI: 10.1002/mp.16764] [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: 06/29/2023] [Revised: 09/15/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Cancer is a highly heterogeneous disease, driven by frequent genetic alterations which have significant effects on radiosensitivity. However, radiotherapy for a given cancer type is typically given with a standard dose determined from population-level trials. As a result, a proportion of patients are under- or over-dosed, reducing the clinical benefit of radiotherapy. Biological optimization would not only allow individual dose prescription but also a more efficient allocation of limited resources, such as proton and carbon ion therapy. Proton and ion radiotherapy offer an advantage over photons due to their elevated Relative Biological Effectiveness (RBE) resulting from their elevated Linear Energy Transfer (LET). Despite significant interest in optimizing LET by tailoring radiotherapy plans, RBE's genetic dependence remains unclear. PURPOSE The aim of this study is to better define the RBE/LET relationship in a panel of cell lines with different defects in DSB repair pathways, but otherwise identical biological features and genetic background to isolate these effects. METHODS Normal human cells (RPE1), genetically modified to introduce defects in DNA double-strand break (DSB) repair genes, ATM, BRCA1, DCLRE1C, LIG4, PRKDC and TP53, were used to map the RBE-LET relationship. Cell survival was measured with clonogenic assays after exposure to photons, protons (LET 1 and 12 keV/µm) and alpha particles (129 keV/µm). Gene knockout sensitizer enhancement ratio (SER) values were calculated as the ratio of the mean inactivation dose (MID) of wild-type cells to repair-deficient cells, and RBE values were calculated as the ratio of the MID of X-ray and particle irradiated cells. 53BP1 foci were used to quantify radiation-induced DSBs and their repair following irradiation. RESULTS Deletion of NHEJ genes had the greatest impact on photon sensitivity (ATM-/- SER = 2.0 and Lig4-/- SER = 1.8), with genes associated with HR having smaller effects (BRCA1-/- SER = 1.2). Wild-type cells showed RBEs of 1.1, 1.3, 5.0 for low- and high-LET protons and alpha particles respectively. SERs for different genes were independent of LET, apart from NHEJ knockouts which proved to be markedly hypersensitive across all tested LETs. Due to this hypersensitivity, the impact of high LET was reduced in cell models lacking the NHEJ repair pathway. HR-defective cells had moderately increased sensitivity across all tested LETs, but, notably, the contribution of HR pathway to survival appeared independent of LET. Analysis of 53BP1 foci shows that NHEJ-defective cells had the least DSB repair capacity after low LET exposure, and no visible repair after high LET exposure. HR-defective cells also had slower repair kinetics, but the impact of HR defects is not as severe as NHEJ defects. CONCLUSIONS DSB repair defects, particularly in NHEJ, conferred significant radiosensitivity across all LETs. This sensitization appeared independent of LET, suggesting that the contribution of different DNA repair pathways to survival does not depend on radiation quality.
Collapse
Affiliation(s)
| | - Jason L Parsons
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - Stephen J McMahon
- The Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| |
Collapse
|
10
|
Wang J, Xiang ZZ, Tan CF, Zeng YY, Yang T, Wei XY, Yu ST, Dai ZL, Xu NY, Liu L. Individualized 3D-printed bolus promotes precise postmastectomy radiotherapy in patients receiving breast reconstruction. Front Oncol 2023; 13:1239636. [PMID: 38152364 PMCID: PMC10751906 DOI: 10.3389/fonc.2023.1239636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 11/29/2023] [Indexed: 12/29/2023] Open
Abstract
Purpose To evaluate the efficacy and safety of 3D-printed tissue compensations in breast cancer patients receiving breast reconstruction and postmastectomy radiotherapy (PMRT). Methods and materials We enrolled patients with breast cancer receiving breast reconstruction and PMRT. The dose distribution of target and skin, conformability, and dose limit of organs at risk (OARs) were collected to evaluate the efficacy of the 3D-printed bolus. Radiation Therapy Oncology Group (RTOG) radiation injury classification was used to evaluated the skin toxicities. Results A total of 30 patients diagnosed between October 2019 to July 2021 were included for analysis. Among all the patients, the 3D-printed bolus could ensure the dose coverage of planning target volume (PTV) [homogeneity index (HI) 0.12 (range: 0.08-0.18)], and the mean doses of D99%, D98%, D95%, D50%, D2% and Dmean were 4606.29cGy, 4797.04cGy, 4943.32cGy, 5216.07cGy, 5236.10cGy, 5440.28cGy and 5462.10cGy, respectively. The bolus demonstrated an excellent conformability, and the mean air gaps between the bolus and the chest wall in five quadrants were 0.04cm, 0.18cm, 0.04cm, 0.04cm and 0.07cm, respectively. In addition, the bolus had acceptable dosage limit of OARs [ipsilateral lung: Dmean 1198.68 cGy, V5 46.10%, V20 21.66%, V30 16.31%); heart: Dmean 395.40 cGy, V30 1.02%, V40 0.22%; spinal cord planning risk volume (PRV): Dmax 1634 cGy] and skin toxicity (grade 1, 76.0%; grade 2, 21.0%; grade 3, 3.3%). Conclusion The 3D-printed bolus offers advantages in terms of dose uniformity and controllable skin toxicities in patients receiving breast reconstruction and PMRT. Further research is needed to comprehensively evaluate the effectiveness of the 3Dprinted bolus in this patient subset.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Lei Liu
- Division of Head & Neck Tumor Multimodality Treatment, Cancer Center, West, China Hospital, Sichuan University, Chengdu, Sichuan, China
| |
Collapse
|
11
|
Kaiyum R, Schruder CW, Mermut O, Rink A. Investigation of cyanine-based infrared dyes as calibrants in radiochromic films. Med Phys 2023; 50:8034-8043. [PMID: 37633840 DOI: 10.1002/mp.16674] [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: 05/01/2023] [Revised: 07/03/2023] [Accepted: 07/29/2023] [Indexed: 08/28/2023] Open
Abstract
BACKGROUND Radiochromic material such as lithium pentacosa-10,12-diynoate (LiPCDA) has been suggested as the radiation-sensitive material for real-time in vivo fiber-optic dosimetry. In this configuration, micron-thick radiochromic coating would measure the absorbed dose, where a major challenge is the uncertainty in the active material thickness, necessitating calibration. A homogeneously incorporated inert infrared (IR) dye, which must also be stable in ambient conditions and against radiolysis, can be added to the radiochromic film to enable optical calibration. PURPOSE This study investigates four commercial cyanine-based dyes (IR-783, IR-806, IR-868, and IR-880) for use as an optical calibrant in fiber-optic radiochromic dosimeters. METHODS All dyes were dissolved in water to confirm solubility. IR-783 and IR-806 were dissolved in 10% w/w gelatin solution and coated onto a polyester substrate, which were then sandwiched between two layers of adhesives forming IR-783 and IR-806 films. A second batch of IR dyes in gelatin incorporated the LiPCDA, and was coated onto substrate and sandwiched between adhesive to form IR dye + LiPCDA films. The absorbance spectra of the films were measured periodically (176 and 102 days for IR-dye films, and IR dye + LiPCDA, respectively). The average percentage absorbance, normalized to day 1, was fit to either a single or a double exponential decay model to calculate the spectral stability lifetime (τ1 , τ2 ). Films were irradiated using a 6 MV LINAC beam with a standard setup of 100 source to axis distance (SAD), 10 cm × 10 cm field size and 1.5 cm depth. The change in absorbance of the IR-dye + LiPCDA films were measured after they were irradiated to 1, 2, 5, 10, and 20 Gy at 3 Gy/min. RESULTS Only IR-783 and IR-806 were sufficiently water soluble. In gelatin matrix, these dyes demonstrated a decrease in absorbance with time for IR-783 and IR-806 dyes, with IR-783 films having an average τ1 = 73 ± 7 days and IR-806 films τ1 = 7 ± 3 days. When combined with LiPCDA, IR-806 degraded, losing its original peak at ∼820 nm. Similarly, IR-783, combined with LiPCDA, showed signs of degradation; however, its original absorbance peak was still observed at ∼800 nm. In the IR-783 + LiPCDA films, the IR-783 dye had a τ = 4 ± 1 days, an order of magnitude faster than the IR-783 with no LiPCDA films. When exposed to x-ray irradiation, the IR-783 dye in the IR-783 + LiPCDA films showed no change in absorbance with increasing absorbed dose. In contrast, the LiPCDA in the films responded as expected, increasing in optical density with increased absorbed dose. CONCLUSIONS IR-783 and IR-806 dyes were observed to degrade over time following exponential decay curves. IR-806 could not be combined with the LiPCDA without degrading. The combination of IR-783 with LiPCDA demonstrated single exponential decay behavior at a comparatively faster rate than films that did not have LiPCDA. IR-783 was insensitive to ionizing radiation and thus may be suitable for thickness correction, but an alternative manufacturing procedure may need to be developed.
Collapse
Affiliation(s)
- Rohith Kaiyum
- Department of Physics and Astronomy, York University, Toronto, Canada
- TECHNA Institute, University Health Network, Toronto, Canada
| | - Christopher W Schruder
- Department of Physics and Astronomy, York University, Toronto, Canada
- TECHNA Institute, University Health Network, Toronto, Canada
| | - Ozzy Mermut
- Department of Physics and Astronomy, York University, Toronto, Canada
| | - Alexandra Rink
- Department of Medical Physics, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| |
Collapse
|
12
|
van den Dobbelsteen M, Hackett SL, van Asselen B, Oolbekkink S, Wolthaus JW, de Vries JW, Raaymakers BW. Experimental validation of multi-fraction online adaptations in magnetic resonance guided radiotherapy. Phys Imaging Radiat Oncol 2023; 28:100507. [PMID: 38035206 PMCID: PMC10685304 DOI: 10.1016/j.phro.2023.100507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
Background and purpose Radiotherapy plan verification is generally performed on the reference plan based on the pre-treatment anatomy. However, the introduction of online adaptive treatments demands a new approach, as plans are created daily on different anatomies. The aim of this study was to experimentally validate the accuracy of total doses of multi-fraction plan adaptations in magnetic resonance imaging guided radiotherapy in a phantom study, isolated from the uncertainty of deformable image registration. Materials and methods We experimentally verified the total dose, measured on external beam therapy 3 (EBT3) film, using a treatment with five online adapted fractions. Three series of experiments were performed, each focusing on a category of inter-fractional variation; translations, rotations and body modifications. Variations were introduced during each fraction and adapted plans were generated and irradiated. Single fraction doses and total doses over five online adapted fractions were investigated. Results The online adapted measurements and calculations showed a good agreement for single fractions and multi-fraction treatments for the dose profiles, gamma passing rates, dose deviations and distances to agreement. The gamma passing rate using a 2%/2 mm criterion ranged from 99.2% to 99.5% for a threshold dose of 10% of the maximum dose (Dmax) and from 96.2% to 100% for a threshold dose of 90% of Dmax, for the total translations, rotations and body modifications. Conclusions The total doses of multi-fraction treatments showed similar accuracies compared to single fraction treatments, indicating an accurate dosimetric outcome of a multi-fraction treatment in adaptive magnetic resonance imaging guided radiotherapy.
Collapse
Affiliation(s)
- Madelon van den Dobbelsteen
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Sara L. Hackett
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bram van Asselen
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Stijn Oolbekkink
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Jochem W.H. Wolthaus
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - J.H. Wilfred de Vries
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bas W. Raaymakers
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| |
Collapse
|
13
|
Rana S, Eckert C, Tesfamicael B. Feasibility study of utilizing Sphinx Compact for quality assurance in uniform scanning proton therapy. Phys Med 2023; 113:102468. [PMID: 36336530 DOI: 10.1016/j.ejmp.2022.10.001] [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: 02/27/2022] [Revised: 07/17/2022] [Accepted: 10/07/2022] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To investigate the feasibility of utilizing the Sphinx Compact detector for quality assurance in a uniform scanning proton therapy system. METHOD The Sphinx Compact detector was used to measure various dosimetric parameters of uniform scanning proton beam at the Oklahoma Proton Center: distal range, distal-fall-off, collinearity, field symmetry, flatness, and field size for four different beams. A specially designed brass aperture was used to perform the required measurements. The Sphinx Compact measurement results were validated against the measurement results from the well-established detectors in proton therapy: IBA Zebra, IBA MatriXX-PT, EBT3 films, and Logos XRV-124. The data collected using the Sphinx Compact was analyzed in myQA software. RESULTS Based on the data analysis performed, the Sphinx Compact measurements were within acceptable accuracy to the results from the detectors mentioned in the Method section. Specifically, the lateral penumbra was within ±0.4 mm, collinearity was within ± 0.5 mm, flatness was within ±0.6 %, symmetry within ±1.6 %, distal range was within ±0.5 mm, distal-fall-off was <0.9 mm, and field size was within ±1 mm. The reproducibility of the Sphinx Compact was tested for range and collinearity, and the results were within ±0.1 mm. CONCLUSION The sphinx Compact detector could potentially replace multiple detectors utilized for monthly QA in uniform scanning proton therapy. In a multi-room center, performing the QA with one detector compared to using multiple detectors dramatically reduces total QA time and the complexity of the QA process.
Collapse
Affiliation(s)
- Suresh Rana
- Department of Medical Physics, The Oklahoma Proton Center, Oklahoma City, OK, USA; Department of Radiation Oncology, Lynn Cancer Institute, Boca Raton Regional Hospital, Baptist Health South Florida, Boca Raton, FL, USA; Department of Radiation Oncology, Florida International University, Miami, FL, USA.
| | - Colton Eckert
- Department of Medical Physics, The Oklahoma Proton Center, Oklahoma City, OK, USA
| | - Biniam Tesfamicael
- Department of Medical Physics, The Oklahoma Proton Center, Oklahoma City, OK, USA
| |
Collapse
|
14
|
Palmer AL, Nash D, Polak W, Wilby S. Evaluation of a new radiochromic film dosimeter, Gafchomic EBT4, for VMAT, SABR and HDR treatment delivery verification. Phys Med Biol 2023; 68:175003. [PMID: 37499683 DOI: 10.1088/1361-6560/aceb48] [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: 02/03/2023] [Accepted: 07/27/2023] [Indexed: 07/29/2023]
Abstract
Objective.To evaluate a new film for radiotherapy dosimetry, Gafchromic EBT4, compared to the current EBT3. To evaluate dose-response and verify test cases in MV external beam and HDR brachytherapy.Approach. Three lots (batches) of EBT4 and three lots of EBT3 films were calibrated at 6 MV over 0-1200 cGy range, using FilmQAPro software. Signal-to-noise of pixel value, reported dose (RD), and factors affecting dosimetry accuracy were evaluated (rotation of the film at scanning, energy response and post-exposure darkening). Both films were exposed to clinical treatment plans (VMAT prostate, SABR lung, single HDR source dwell, and 'pseudo' 3-channel HDR cervix brachytherapy). Film-RD was compared to TPS-calculated dose.Main results.EBT4 calibration curves had characteristics more favourable than EBT3 for radiation dosimetry, with improved signal to noise in film-RD of EBT4 compared to EBT3 (increase of average 46% in red and green channels at 500 cGy). Film rotation at scanning and post-exposure darkening was similar for the two films. The energy response of EBT4 is similar to EBT3. For all clinical case studies, EBT4 provided better agreement with the TPS-planned doses than EBT3. VMAT prostate gamma 3%/3 mm passing rate, EBT4 100.0% compared to EBT3 97.9%; SABR lung gamma 2%/2 mm, EBT4 99.6% and EBT3 97.9%; HDR cervix gamma 3%/2 mm, EBT4 97.7% and EBT3 95.0%.Significance.These results show EBT4 is superior to EBT3 for radiotherapy dosimetry validation of TPS plan delivery. Fundamental improvements in noise profile and calibration curve are reported for EBT4. All clinical test cases showed EBT4 provided equivalent or smaller difference in measured dose to TPS calculated dose than EBT3. Baseline data is presented on the achievable accuracy of film dosimetry in radiotherapy using the new Gafchromic EBT4 film.
Collapse
Affiliation(s)
- Antony L Palmer
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| | - David Nash
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| | - Wojciech Polak
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| | - Sarah Wilby
- Medical Physics Dept, Portsmouth Hospitals University NHS Trust, Cosham, PO6 3LY, United Kingdom
| |
Collapse
|
15
|
Endarko E, Aisyah S, Hariyanto AP, Haekal M, Kavilani N, Syafi'i A. Dosimetry Evaluation of Treatment Planning Systems in Patient-Specific 3D Printed Anthropomorphic Phantom for Breast Cancer after Mastectomy using a Single-Beam 3D-CRT Technique for Megavoltage Electron Radiation Therapy. J Biomed Phys Eng 2023; 13:217-226. [PMID: 37312896 PMCID: PMC10258204 DOI: 10.31661/jbpe.v0i0.2111-1428] [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] [Received: 11/08/2021] [Accepted: 03/20/2022] [Indexed: 06/15/2023]
Abstract
Background The patient-specific 3D printed anthropomorphic phantom is used for breast cancer after mastectomy developed by the laboratory of medical physics and biophysics, Department of Physics, Institut Teknologi Sepuluh Nopember, Indonesia. This phantom is applied to simulate and measure the radiation interactions occurring in the human body either using the treatment planning system (TPS) or direct measurement with external beam therapy (EBT) 3 film. Objective This study aimed to provide dose measurements in the patient-specific 3D printed anthropomorphic phantom using a TPS and direct measurements using single-beam three-dimensional conformal radiation therapy (3DCRT) technique with electron energy of 6 MeV. Material and Methods In this experimental study, the patient-specific 3D printed anthropomorphic phantom was used for post-mastectomy radiation therapy. TPS on the phantom was conducted using a 3D-CRT technique with RayPlan 9A software. The single-beam radiation was delivered to the phantom with an angle perpendicular to the breast plane at 337.3° at 6 MeV with a total prescribed dose of 5000 cGy/25 fractions with 200 cGy per fraction. Results The doses at planning target volume (PTV) and right lung confirmed a non-significant difference both for TPS and direct measurement with P-values of 0.074 and 0.143, respectively. The dose at the spinal cord showed statistically significant differences with a P-value of 0.002. The result presented a similar skin dose value using either TPS or direct measurement. Conclusion The patient-specific 3D printed anthropomorphic phantom for breast cancer after mastectomy on the right side has good potential as an alternative to the evaluation of dosimetry for radiation therapy.
Collapse
Affiliation(s)
- Endarko Endarko
- Department of Physics, Institut Teknologi Sepuluh Nopember, Kampus ITS - Sukolilo Surabaya 60111, East Java, Indonesia
| | - Siti Aisyah
- Medical Physicist of Radiotherapy Installation, Naval Hospital Dr. Ramelan, Surabaya 60244, East Java, Indonesia
| | - Aditya Prayugo Hariyanto
- Department of Physics, Institut Teknologi Sepuluh Nopember, Kampus ITS - Sukolilo Surabaya 60111, East Java, Indonesia
| | - Mohammad Haekal
- Department of Physics, Institut Teknologi Sepuluh Nopember, Kampus ITS - Sukolilo Surabaya 60111, East Java, Indonesia
| | - Nandia Kavilani
- Medical Physicist of Radiotherapy Installation, Naval Hospital Dr. Ramelan, Surabaya 60244, East Java, Indonesia
| | - Ahmad Syafi'i
- Medical Physicist of Radiotherapy Installation, Naval Hospital Dr. Ramelan, Surabaya 60244, East Java, Indonesia
| |
Collapse
|
16
|
Cheon BW, Lee HC, You SH, Seo H, Min CH, Choi HJ. Experiment of proof-of-principle on prompt gamma-positron emission tomography (PG-PET) system for in-vivo dose distribution verification in proton therapy. NUCLEAR ENGINEERING AND TECHNOLOGY 2023. [DOI: 10.1016/j.net.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
|
17
|
Trivedi G, Singh PP, Oinam AS. Comparison of single catheter versus dual catheter-based EBT3 film calibration for the Ir-192 beam energy. Biomed Phys Eng Express 2023; 9. [PMID: 36796085 DOI: 10.1088/2057-1976/acbc80] [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: 09/16/2022] [Accepted: 02/16/2023] [Indexed: 02/18/2023]
Abstract
Purpose. Films and TLDs have been the common choices for passivein-vivodose measurement in radiotherapy. In the brachytherapy applications, it is very difficult to report and verify the dose at multiple localized high dose gradient regions and also the dose to organ at risk. This study was carried out to introduce a new and accurate calibration method for GafChromic EBT3 films irradiated using Ir-192 photon energy from miniature High Dose Rate (HDR) Brachytherapy source.Materials and methods. Film holder made of Styrofoam was used to hold the EBT3 film at its center. It was placed inside the mini water phantom and the films were irradiated by Ir-192 source of microSelectron HDR afterloading brachytherapy system. Two different setups: Single catheter-based film exposure and dual catheter-based film exposure were compared. The films scanned on a flatbed scanner were analysed in three different color channels: red, green, and blue using Image J software. The dose calibration graphs were generated using the third-order polynomial equations fitted on the data points from two different methods of calibration procedure. Maximum and mean dose difference between TPS calculated and measured was analyzed.Results. The measured dose difference from the TPS calculated doses were evaluated for the three groups of dose ranges (low, medium and high). In the high dose range, standard uncertainty of dose difference are ±2.3%, ±2.9%, and ±2.4% respectively for the red, green, and blue color channel when the TPS calculated dose was compared with single catheter based film calibration equation. Whereas it is observed as 1.3%, 1.4% and 3.1% for the red, green, and blue color channels respectively when compared with the dual catheter based film calibration equation. A test film was exposed to a TPS calculated dose of 666 cGy to validate the calibration equations, single catheter based film calibration equation estimated the dose difference as -9.2%, -7.8% and -3.6% respectively in the red, green, and blue color channels whereas the same were observed as 0.1%, 0.2% and 6.1% respectively when dual catheter based film calibration equation was applied.Conclusion.Source miniature size, reproducible positioning of the film and catheter system inside water medium are the major challenges in the film calibration with Ir-192 beam. To overcome these situations dual catheter-based film calibration was found more accurate and reproducible as compare to the single catheter based film calibration.
Collapse
Affiliation(s)
- Gaurav Trivedi
- Post Graduate Institute of Medical Education and Research, India.,Indian Institute of Technology, Ropar, India
| | | | - Arun S Oinam
- Post Graduate Institute of Medical Education and Research, India
| |
Collapse
|
18
|
Behrends C, Bäumer C, Verbeek NG, Wulff J, Timmermann B. Optimization of proton pencil beam positioning in collimated fields. Med Phys 2023; 50:2540-2551. [PMID: 36609847 DOI: 10.1002/mp.16209] [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: 10/13/2022] [Revised: 12/24/2022] [Accepted: 12/26/2022] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The addition of static or dynamic collimator systems to the pencil beam scanning delivery technique increases the number of options for lateral field shaping. The collimator shape needs to be optimized together with the intensity modulation of spots. PURPOSE To minimize the proton field's lateral penumbra by investigating the fundamental relations between spot and collimating aperture edge position. METHODS Analytical approaches describing the effect of spot position on the resulting spot profile are presented. The theoretical description is then compared with Monte Carlo simulations in TOPAS and in the RayStation treatment planning system, as well as with radiochromic film measurements at a clinical proton therapy facility. In the model, one single spot profile is analyzed for various spot positions in air. Further, irradiation setups in water with different energies, the combination with a range shifter, and two-dimensional proton fields were investigated in silico. RESULTS The further the single spot is placed beyond the collimating aperture edge ('overscanning'), the sharper the relative lateral dose fall-off and thus the lateral penumbra. Overscanning up to 5 mm $5\,\text{mm}$ reduced the lateral penumbra by about 20% on average after a propagation of 13 cm $13\,\text{cm}$ in air. This benefit from overscanning is first predicted by the analytical proofs and later verified by simulations and measurements. Corresponding analyses in water confirm the benefit in lateral penumbra with spot position optimization as observed theoretically and in air. The combination of spot overscanning with fluence modulation facilitated an additional improvement. CONCLUSIONS The lateral penumbra of single spots in collimated scanned proton fields can be improved by the method of spot overscanning. This suggests a better sparing of proximal organs at risk in smaller water depths at higher energies, especially in the plateau of the depth dose distribution. All in all, spot overscanning in collimated scanned proton fields offers particular potential in combination with techniques such as fluence modulation or dynamic collimation for optimizing the lateral penumbra to spare normal tissue.
Collapse
Affiliation(s)
- Carina Behrends
- West German Proton Therapy Centre Essen (WPE), Essen, Germany.,Department of Physics, TU Dortmund University, Dortmund, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen (WPE), Essen, Germany.,Department of Physics, TU Dortmund University, Dortmund, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Nico Gerd Verbeek
- West German Proton Therapy Centre Essen (WPE), Essen, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, Essen, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany
| | - Jörg Wulff
- West German Proton Therapy Centre Essen (WPE), Essen, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, Essen, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen (WPE), Essen, Germany.,West German Cancer Centre (WTZ), University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany.,Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.,Department of Particle Therapy, University Hospital Essen, Essen, Germany
| |
Collapse
|
19
|
Baba MH, Singh BK, Wani SQ. In vivo Dosimetry for Dose Verification of Total Skin Electron Beam Therapy Using Gafchromic® EBT3 Film Dosimetry. J Med Phys 2022; 47:362-366. [PMID: 36908494 PMCID: PMC9997533 DOI: 10.4103/jmp.jmp_72_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/30/2022] [Accepted: 10/16/2022] [Indexed: 01/11/2023] Open
Abstract
Background and Purpose Total skin electron beam therapy (TSEBT) is an important skin-directed radiotherapeutic procedure done in the treatment of cutaneous T-cell lymphomas, namely, mycosis fungoides (MF). This procedure is usually done at larger source-to-surface distances with the patient standing on a rotatory platform. As the patient has to stand in different positions without any rigid immobilization devices, there are chances that the total skin may not get uniformly irradiated which could lead to nonuniform dose distributions. Therefore, all the necessary arrangements should be made to evaluate the dose for different regions of the skin using suitable in vivo dosimeters at the radiotherapy centers offering these treatments. This study aimed to evaluate the consistency between the delivered and planned doses in vivo during TSEBT using Gafchromic EBT3 film dosimetry. Materials and Methods The surface dose for the six MF patients treated for TSEBT at our hospital from 2018 to 2022 was measured and evaluated. 2 cm × 2 cm Gafchromic® EBT3 films were used to measure skin dose at reference body positions of clinical interest. All the patients were treated with the modified Stanford technique. The irradiated film strips were analyzed for the dose using the IMRT OmniPro software. The doses at respective positions were expressed as mean dose ± standard deviation and the deviation was calculated as the percentage of the prescribed dose. Results One hundred and fifty-four Gafchromic® EBT3 film strips irradiated on six TSEBT patients showed a maximum dose variation of 2.00 ± 0.14 Gy, in the central body regions. The dose variation in the peripheral areas such as hands and ears was larger. A variation of 2 ± 0.32 Gy was observed on the hands and ears. The uniformity of the dose delivered to maximum body parts was within -7% and +16% for the peripheral areas like hands. The American Association of Physicists in Medicine recommends a dose uniformity of 8% and 4% in the vertical and horizontal patient plane for direct incident beam; however, for oblique incidences like in the modified Stanford technique, the dose variation is about 15%. Conclusion In vivo dosimetry using Gafchromic EBT3 film dosimetry for TSEBT yields objective data to find the under or overdose regions. That can be useful to provide quality treatment, especially when treatments tend to be as complex as TSEBT.
Collapse
Affiliation(s)
- Misba Hamid Baba
- Department of Physics, Institute of Applied Sciences and Humanities, GLA University, Mathura, Uttar Pradesh, India
- Department of Radiological Physics and B.E, Sher I Kashmir Institute of Medical Sciences, Srinagar, Jammu and Kashmir, India
| | - Benoy Kumar Singh
- Department of Physics, Institute of Applied Sciences and Humanities, GLA University, Mathura, Uttar Pradesh, India
| | - Shaqul Qamar Wani
- Department of Radiation Oncology, Sher I Kashmir Institute of Medical Sciences, Srinagar, Jammu and Kashmir, India
| |
Collapse
|
20
|
Baba MH, Singh BK. In-vivo skin dose measurement using gafchromic EBT3 film dosimetry in the radiation therapy of Head and Neck cancers: 2DRT versus IMRT. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2022. [DOI: 10.1016/j.jrras.2022.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
21
|
Cavallone M, Jorge PG, Moeckli R, Bailat C, Flacco A, Prezado Y, Delorme R. Determination of the ion collection efficiency of the Razor Nano Chamber for ultra-high dose-rate electron beams. Med Phys 2022; 49:4731-4742. [PMID: 35441716 PMCID: PMC9539950 DOI: 10.1002/mp.15675] [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] [Received: 10/11/2021] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 11/10/2022] Open
Abstract
Background Ultra‐high dose‐rate (UHDR) irradiations (>40 Gy/s) have recently garnered interest in radiotherapy (RT) as they can trigger the so‐called “FLASH” effect, namely a higher tolerance of normal tissues in comparison with conventional dose rates when a sufficiently high dose is delivered to the tissue. To transfer this to clinical RT treatments, adapted methods and practical tools for online dosimetry need to be developed. Ionization chambers remain the gold standards in RT but the charge recombination effects may be very significant at such high dose rates, limiting the use of some of these dosimeters. The reduction of the sensitive volume size can be an interesting characteristic to reduce such effects. Purpose In that context, we have investigated the charge collection behavior of the recent IBA Razor™ Nano Chamber (RNC) in UHDR pulses to evaluate its potential interest for FLASH RT. Methods In order to quantify the RNC ion collection efficiency (ICE), simultaneous dose measurements were performed under UHDR electron beams with dose‐rate‐independent Gafchromic™ EBT3 films that were used as the dose reference. A dose‐per‐pulse range from 0.01 to 30 Gy was investigated, varying the source‐to‐surface distance, the pulse duration (1 and 3 μs investigated) and the LINAC gun grid tension as irradiation parameters. In addition, the RNC measurements were corrected from the inherent beam shot‐to‐shot variations using an independent current transformer. An empirical logistic model was used to fit the RNC collection efficiency measurements and the results were compared with the Advanced Markus plane parallel ion chamber. Results The RNC ICE was found to decrease as the dose‐per‐pulse increases, starting from doses above 0.2 Gy/pulse and down to 40% of efficiency at 30 Gy/pulse. The RNC resulted in a higher ICE for a given dose‐per‐pulse in comparison with the Markus chamber, with a measured efficiency found higher than 85 and 55% for 1 and 10 Gy/pulse, respectively, whereas the Markus ICE was of 60 and 25% for the same doses. However, the RNC shows a higher sensitivity to the pulse duration than the Advanced Markus chamber, with a lower efficiency found at 1 μs than at 3 μs, suggesting that this chamber could be more sensitive to the dose rate within the pulse. Conclusions The results confirmed that the small sensitive volume of the RNC ensures higher ICE compared with larger chambers. The RNC was thus found to be a promising online dosimetry tool for FLASH RT and we proposed an ion recombination model to correct its response up to extreme dose‐per‐pulses of 30 Gy.
Collapse
Affiliation(s)
- Marco Cavallone
- Institut Curie, PSL Research University, Radiation Oncology Department, Proton Therapy Centre, Centre Universitaire, Orsay, 91898, France.,Laboratoire d'Optique Appliquée, ENSTA Paris, École Polytechnique, CNRS-UMR7639, Institut Polytechnique de Paris, Palaiseau Cedex, 91762, France
| | | | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Alessandro Flacco
- Laboratoire d'Optique Appliquée, ENSTA Paris, École Polytechnique, CNRS-UMR7639, Institut Polytechnique de Paris, Palaiseau Cedex, 91762, France
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France.,Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, Orsay, 91400, France
| | - Rachel Delorme
- University of Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, Grenoble, 38000, France.,Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), CNRS Univ Paris-Sud, Université Paris-Saclay, Orsay, F-91400, France
| |
Collapse
|
22
|
Abu Mhanna HY, Omar AF, Radzi YM, Akhdar HF, Al Ewaidat H. Expired EBT3 Films’ Sensitivity for the Measurement of X-ray and UV Radiation: An Optical Analysis. MATERIALS 2022; 15:ma15082903. [PMID: 35454597 PMCID: PMC9027090 DOI: 10.3390/ma15082903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/15/2022] [Accepted: 04/13/2022] [Indexed: 11/25/2022]
Abstract
The aim of this study is to compare the optical responses of external beam therapy 3 (EBT3) films exposed to X-rays and solar ultraviolet rays (SUV-rays), as a dose control technique in the clinical sector for various radiation types, energies, and absorbed doses up to 4 Gy. In this study, EBT3 films with three different expiry dates were prepared and cut into pieces of size 2 by 2 cm2. The first group was exposed to 90 kVp X-rays, while the second group was exposed to the SUV-rays at noon. The analysis was performed using a visible Jaz spectrometer and an EPSON Perfection V370 Photo scanner to obtain the absorbance, the net reflective optical density (ROD) and the red-green-blue (RGB) values of the samples. The results have shown that spectroscopic measurements of the exposed expired EBT3 films with these radiation sources are able to produce primary peaks and secondary peaks at λ = 641.74 nm and λ = 585.98 nm for X-rays, and at λ = 637.93 nm and λ = 584.45 nm for SUV-rays, respectively. According to these findings, compared to 2021 films that expired shortly before the trial start date; 2018 films responded better to the absorbed dose than 2016 films when exposed to both X-ray and SUV-rays. In terms of energy dependence, the expired EBT3 2018 had the largest net ROD value. Using L*a*b* indices extracted from the RGB data, and despite that EBT3 films have expiry dates according to the manufacturer; all the films exhibited a substantial colour change, indicating that these films are still usable for clinical and research purposes.
Collapse
Affiliation(s)
- Hamad Yahia Abu Mhanna
- School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia;
- Correspondence: (H.Y.A.M.); (A.F.O.); (H.F.A.)
| | - Ahmad Fairuz Omar
- School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia;
- Correspondence: (H.Y.A.M.); (A.F.O.); (H.F.A.)
| | - Yasmin Md Radzi
- School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia;
| | - Hanan Fawaz Akhdar
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia
- Correspondence: (H.Y.A.M.); (A.F.O.); (H.F.A.)
| | - Haytham Al Ewaidat
- Department of Allied Medical Sciences-Radiologic Technology, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan;
| |
Collapse
|
23
|
Pawałowski B, Ryczkowski A, Panek R, Sobocka-Kurdyk U, Graczyk K, Piotrowski T. Accuracy of the doses computed by the Eclipse treatment planning system near and inside metal elements. Sci Rep 2022; 12:5974. [PMID: 35396569 PMCID: PMC8993896 DOI: 10.1038/s41598-022-10072-8] [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: 01/27/2022] [Accepted: 03/25/2022] [Indexed: 11/09/2022] Open
Abstract
Metal artefacts degrade clinical image quality which decreases the confidence of using computed tomography (CT) for the delineation of key structures for treatment planning and leads to dose errors in affected areas. In this work, we investigated accuracy of doses computed by the Eclipse treatment planning system near and inside metallic elements for two different computation algorithms. An impact of CT metal artefact reduction methods on the resulting calculated doses has also been assessed. A water phantom including Gafchromic film and metal inserts was irradiated (max dose 5 Gy) using a 6 MV photon beam. Three materials were tested: titanium, alloy 600, and tungsten. The phantom CT images were obtained with the pseudo-monoenergetic reconstruction (PMR) and the iterative metal artefact reduction (iMAR). Image sets were used for dose calculation using an Eclipse treatment planning station (TPS). Monte Carlo (MC) simulations were used to predict the true dose distribution in the phantom allowing for comparison with doses measured by film and calculated by TPS. Measured and simulated percentage depth doses (PDDs) were not statistically different (p > 0.618). Regional differences were observed at edges of metallic objects (max 8% difference). However, PDDs simulated with and without film were statistically different (p < 0.002). PDDs calculated by the Acuros XB algorithm based on the dose-to-medium approach best matched the MC reference regardless of the CT reconstruction methods and inserts used (p > 0.078). PDDs obtained using other algorithms significantly differ from the MC values (p < 0.011). The Acuros XB algorithm with a dose-to-medium approach provides reliable dose calculation in all metal regions when using the Varian system. The inability of the AAA algorithm to model backscatter dose significantly limits its clinical application in the presence of metal. No significant impact on the dose calculation was found for a range of metal artefact reduction strategies.
Collapse
Affiliation(s)
- Bartosz Pawałowski
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland.,Department of Technical Physics, Poznan University of Technology, Poznan, Poland
| | - Adam Ryczkowski
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland.,Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Rafał Panek
- Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham, UK.,School of Medicine, University of Nottingham, Nottingham, UK
| | - Urszula Sobocka-Kurdyk
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland.,Faculty of Health Sciences, Calisia University, Kalisz, Poland
| | - Kinga Graczyk
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland
| | - Tomasz Piotrowski
- Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15, 61-866, Poznan, Poland. .,Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland.
| |
Collapse
|
24
|
Tegaw EM, Geraily G, Gholami S, Shojaei M, Tadesse GF. Gold-nanoparticle-enriched breast tissue in breast cancer treatment using the INTRABEAM® system: a Monte Carlo study. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2022; 61:119-131. [PMID: 34860272 DOI: 10.1007/s00411-021-00954-2] [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: 01/09/2021] [Accepted: 11/07/2021] [Indexed: 06/13/2023]
Abstract
Using a 50-kV INTRABEAM® system after breast-conserving surgery, breast skin injury and long treatment time remain the challenging problems when large-size spherical applicators are used. This study has aimed to address these problems using gold (Au) nanoparticles (NPs). For this, surface and isotropic doses were measured using a Gafchromic EBT3 film and a water phantom. The particle propagation code EGSnrc/Epp was used to score the corresponding doses using a geometry similar to that used in the measurements. The simulation was validated using a gamma index of 2%/2 mm acceptance criterion in the gamma analysis. After validation Au-NP-enriched breast tissue was simulated to quantify any breast skin dose reduction and shortening of treatment time. It turned out that the gamma value deduced for validation of the simulation was in an acceptable range (i.e., less than one). For 20 mg-Au/g-breast tissue, the calculated Dose Enhancement Ratio (DER) of the breast skin was 0.412 and 0.414 using applicators with diameters of 1.5 cm and 5 cm, respectively. The corresponding treatment times were shortened by 72.22% and 72.30% at 20 mg-Au/g-breast tissue concentration, respectively. It is concluded that Au-NP-enriched breast tissue shows significant advantages, such as reducing the radiation dose received by the breast skin as well as shortening the treatment time. Additionally, the DERs were not significantly dependent on the size of the applicators.
Collapse
Affiliation(s)
- Eyachew Misganew Tegaw
- Department of Physics, Faculty of Natural and Computational Sciences, Debre Tabor University, Debre Tabor, Ethiopia
| | - Ghazale Geraily
- Department of Medical Physics and Biomedical Engineering, School of Medicine, International Campus (TUMS-IC), Tehran University of Medical Sciences, Tehran, Iran.
| | - Somayeh Gholami
- Radiation Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Shojaei
- Department of Medical Physics and Biomedical Engineering, School of Medicine, International Campus (TUMS-IC), Tehran University of Medical Sciences, Tehran, Iran
| | - Getu Ferenji Tadesse
- Department of Physics, College of Natural and Computational Sciences, Aksum University, Axum, Ethiopia
| |
Collapse
|
25
|
Huang L, Gaballa H, Chang J. Evaluating dosimetric accuracy of the 6 MV calibration on EBT3 film in the use of Ir-192 high dose rate brachytherapy. J Appl Clin Med Phys 2022; 23:e13571. [PMID: 35226398 PMCID: PMC9121041 DOI: 10.1002/acm2.13571] [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] [Received: 09/23/2021] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose To evaluate the dosimetric accuracy of EBT3 film calibrated with a 6 MV beam for high dose rate brachytherapy and propose a novel method for direct film calibration with an Ir‐192 source. Methods The 6 MV calibration was performed in water on a linear accelerator (linac). The Ir‐192 calibration was accomplished by irradiating the film wrapped around a cylinder applicator with an Ir‐192 source. All films were scanned 1‐day post‐irradiation to acquire calibration curves for all three (red, blue, and green) channels. The Ir‐192 calibration films were also used for single‐dose comparison. Moreover, an independent test film under a H.A.M. applicator was irradiated and the 2D dose distribution was obtained separately for each calibration using the red channel data. Gamma analysis and point‐by‐point profile comparison were performed to evaluate the performance of both calibrations. The uncertainty budget for each calibration system was analyzed. Results The red channel had the best performance for both calibration systems in the single‐dose comparison. We found a significant 4.89% difference from the reference for doses <250 cGy using the 6 MV calibration, while the difference was only 0.87% for doses >600 cGy. Gamma analysis of the 2D dose distribution showed the Ir‐192 calibration had a higher passing rate of 91.9% for the 1 mm/2% criterion, compared to 83.5% for the 6 MV calibration. Most failing points were in the low‐dose region (<200 cGy). The point‐by‐point profile comparison reported a discrepancy of 2%–3.6% between the Ir‐192 and 6 MV calibrations in this low‐dose region. The linac‐ and Ir‐192‐based dosimetry systems had an uncertainty of 4.1% (k = 2) and 5.66% (k = 2), respectively. Conclusions Direct calibration of EBT3 films with an Ir‐192 source is feasible and reliable, while the dosimetric accuracy of 6 MV calibration depends on the dose range. The Ir‐192 calibration should be used when the measurement dose range is below 250 cGy.
Collapse
Affiliation(s)
- Lyu Huang
- Department of Radiation Medicine, Center for Advanced Medicine, Northwell Health, New Hyde Park, New York, USA
| | - Hani Gaballa
- Department of Radiation Medicine, Center for Advanced Medicine, Northwell Health, New Hyde Park, New York, USA
| | - Jenghwa Chang
- Department of Radiation Medicine, Center for Advanced Medicine, Northwell Health, New Hyde Park, New York, USA.,Department of Radiation Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, New York, USA.,Department of Physics and Astronomy, Hofstra University, Hempstead, New York, USA
| |
Collapse
|
26
|
Villoing D, Koumeir C, Bongrand A, Guertin A, Haddad F, Métivier V, Poirier F, Potiron V, Servagent N, Supiot S, Delpon G, Chiavassa S. Proton beam dosimetry at ultra-high dose rates (FLASH): evaluation of GAFchromic™ (EBT3, EBT-XD) and OrthoChromic (OC-1) film performances. Med Phys 2022; 49:2732-2745. [PMID: 35179234 DOI: 10.1002/mp.15526] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/06/2021] [Accepted: 01/31/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The ARRONAX cyclotron facility offers the possibility to deliver proton beams from low to ultra-high dose rates (UHDR). As a good control of the dosimetry is a prerequisite of UHDR experimentations, we evaluated in different conditions the usability and the dose rate dependency of several radiochromic films commonly used for dosimetry in radiotherapy. METHODS We compared the dose rate dependency of three types of radiochromic films: EBT3 and EBT-XD (GAFchromic™), and OC-1 (OrthoChrome Inc.), after proton irradiations at various mean dose rates (0.25, 40, 1500 and 7500 Gy/s) and for 10 doses (2-130 Gy). We also evaluated the dose rate dependency of each film considering beam structures, from single pulse to multiple pulses with various frequencies. RESULTS EBT3 and EBT-XD films showed differences of response between conventional (0.25 Gy/s) and UHDR (7500 Gy/s) conditions, above 10 Gy. On the contrary, OC-1 films did not present overall difference of response for doses except below 3 Gy. We observed an increase of the netOD with the mean dose rate for EBT3 and EBT-XD films. OC-1 films did not show any impact of the mean dose rate up to 7500 Gy/s, above 3 Gy. No difference was found based on the beam structure, for all three types of films. CONCLUSIONS EBT3 and EBT-XD radiochromic films should be used with caution for the dosimetry of UHDR proton beams over 10 Gy. Their overresponse, which increases with mean dose rate and dose, could lead to non-negligible overestimations of the absolute dose. OC-1 films are dose rate independent up to 7500Gy/s in proton beams. Films response is not impacted by the beam structure. A broader investigation of the usability of OC-1 films in UHDR conditions should be conducted at intermediate and higher mean dose rates and other beam energies. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
| | | | | | - Arnaud Guertin
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | - Ferid Haddad
- GIP ARRONAX, Saint-Herblain, France.,Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | - Vincent Métivier
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | | | | | - Noël Servagent
- Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | | | - Grégory Delpon
- Institut de Cancérologie de l'Ouest, Saint-Herblain, France.,Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| | - Sophie Chiavassa
- Institut de Cancérologie de l'Ouest, Saint-Herblain, France.,Laboratoire SUBATECH, UMR 6457, CNRS IN2P3, IMT Atlantique, Université de Nantes, France
| |
Collapse
|
27
|
Entezam A, Fielding A, Moi D, Bradley D, Ratnayake G, Sim L, Kralik C, Fontanarosa D. Investigation of scattered dose in a mouse phantom model for pre-clinical dosimetry studies. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
28
|
Yang B, Tang KK, Huang CY, Geng H, Lam WW, Wong YS, Tse MY, Lau KK, Cheung KY, Yu SK. Out-of-field dose and its constituent components for a 1.5 T MR-Linac. Phys Med Biol 2021; 66. [PMID: 34700308 DOI: 10.1088/1361-6560/ac3346] [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: 08/07/2021] [Accepted: 10/26/2021] [Indexed: 11/11/2022]
Abstract
This study aims to quantify the relative contributions of phantom scatter, collimator scatter and head leakage to the out-of-field doses (OFDs) of both static fields and clinical intensity-modulated radiation therapy (IMRT) treatments in a 1.5 T MR-Linac. The OFDs of static fields were measured at increasing distances from the field edge in an MR-conditional water phantom. Inline scans at depths of dmax (14 mm), 50 and 100 mm were performed for static fields of 5 × 5, 10 × 10 and 15 × 15 cm2under three different conditions: full scatter, with phantom scatter prevented, and head leakage only. Crossline scans at isocenter and offset positions were performed in full scatter condition. EBT3 radiochromic films were placed at 100 mm depth of solid water phantom to measure the OFD of clinical IMRT plans. All water tank data were normalized to Dmax of a 10 × 10 cm2field and the film results were presented as a fraction of the target mean dose.The OFD in the inline direction varied from 3.5% (15 × 15 cm2, 100 mm depth, 50 mm distance) to 0.014% (5 × 5 cm2, dmax, 400 mm distance). For all static fields, the collimator scatter was higher than the phantom scatter and head leakage at a distance of 100-400 mm. Head leakage remained the smallest among the three components, except at long distances (>375 mm) with small field size. Compared to the inline scans, the crossline scans at the isocenter showed higher doses at distances longer than 80 mm. All crossline profiles at longitudinal offset positions showed a cone shape with laterally shifted maxima. The OFD of IMRT deliveries varied with different target size. For prostate stereotactic body radiation therapy (SBRT) treatment, the OFD decreased from 2% to 0.03% at a distance of 50-500 mm. The OFDs have been measured for a 1.5 T MR-Linac. The presented dosimetric data are valuable for radiation safety assessments on patients treated with the MR-Linac, such as evaluating carcinogenic risk and radiation exposure to cardiac implantable electronic devices.
Collapse
Affiliation(s)
- Bin Yang
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Ka Keung Tang
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Chen-Yu Huang
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Hui Geng
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Wai Wang Lam
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Yeung Sum Wong
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Mei Yan Tse
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Ka Ki Lau
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Kin Yin Cheung
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| | - Siu Ki Yu
- Medical Physics Department, Hong Kong Sanatorium & Hospital, 2 Village Road, Happy Valley, Hong Kong, People's Republic of China
| |
Collapse
|
29
|
Tudda A, Donzelli E, Nicolini G, Semperboni S, Bossi M, Cavaletti G, Castriconi R, Mangili P, Vecchio AD, Sarno A, Mettivier G, Russo P. Breast radiotherapy with kilovoltage photons and gold nanoparticles as radiosensitizer: An in vitro study. Med Phys 2021; 49:568-578. [PMID: 34778990 PMCID: PMC9299863 DOI: 10.1002/mp.15348] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 10/21/2021] [Accepted: 10/25/2021] [Indexed: 11/10/2022] Open
Abstract
Purpose We investigated the dose enhancement and internalization of gold nanoparticles (AuNPs) used as a radiosensitizer agent for rotational radiotherapy of breast cancer using a kilovoltage (kV) X‐ray beam. Methods Human breast cancer cells MDA‐MB‐231 were incubated with or without 100 μg/mL (4.87 nM) or 200 μg/mL (9.74 nM) 15 nm AuNPs and irradiated with 100 kV, 190 kV, or 6 MV X‐rays. To assess the toxicity of the AuNPs, we performed a Sulforhodamine B assay. Using atomic absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, and time‐lapse optical microscopy (rate of 2 frames per minute), we carried out a quantitative assessment of the amount of gold internalized by MDA‐MB‐231 cells and a characterization of the static and dynamical aspects of this internalization process. Results No effect of AuNPs alone was shown on cell viability. Time‐lapse optical microscopy showed for the first time AuNPs cellular uptake and the dynamics of AuNPs internalization. Electron microscopy demonstrated AuNPs localization in endosomal vesicles, preferentially in the perinuclear region. After irradiation at doses up to 2 Gy, cell survival fraction curves showed increased mortality with AuNPs, with respect to irradiation without AuNPs. The highest effect of radioenhancement by AuNPs (at 9.74 nM AuNPs concentration) was observed at 190 kV showing a dose enhancement factor of 1.33 ± 0.06 (1.34 ± 0.02 at 100 kV), while at 6 MV it was 1.14 ± 0.06. Conclusions The observed radio‐sensitization effect is promising for future radio‐enhanced kV radiotherapy of breast cancer and quantitatively in the order of previous observations for 15 nm AuNPs. These results of a significant dose enhancement were obtained at 15 nm AuNPs concentration as low as several nanomolar units, at dose levels typical of a single dose fraction in a radiotherapy session. Dynamical behavior of the 3D spatial distribution of 15 nm AuNPs outside the nucleus of single breast cancer cell was observed, with possible implications for future models of AuNPs sensitization.
Collapse
Affiliation(s)
- Alessia Tudda
- Department of Physics "Ettore Pancini", University of Naples Federico II, Naples, Italy.,INFN Division of Naples, Naples, Italy.,Medical Physics Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.,Department of Physics, Specialty School of Medical Physics, University of Milan, Milan, Italy
| | - Elisabetta Donzelli
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,INFN Division of Milano-Bicocca, Milan, Italy
| | - Gabriella Nicolini
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,INFN Division of Milano-Bicocca, Milan, Italy
| | - Sara Semperboni
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,INFN Division of Milano-Bicocca, Milan, Italy
| | - Mario Bossi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Guido Cavaletti
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Roberta Castriconi
- Medical Physics Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.,INFN Division of Milan, Milan, Italy
| | - Paola Mangili
- Medical Physics Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.,INFN Division of Milan, Milan, Italy
| | - Antonella Del Vecchio
- Medical Physics Department, IRCCS San Raffaele Scientific Institute, Milan, Italy.,INFN Division of Milan, Milan, Italy
| | - Antonio Sarno
- Department of Physics "Ettore Pancini", University of Naples Federico II, Naples, Italy.,INFN Division of Naples, Naples, Italy
| | - Giovanni Mettivier
- Department of Physics "Ettore Pancini", University of Naples Federico II, Naples, Italy.,INFN Division of Naples, Naples, Italy
| | - Paolo Russo
- Department of Physics "Ettore Pancini", University of Naples Federico II, Naples, Italy.,INFN Division of Naples, Naples, Italy
| |
Collapse
|
30
|
Song Z, Yan H, Xu Y, Dai J. A two-layer cylinder phantom developed for film-based isocenter verification of radiotherapy machine. Med Phys 2021; 48:7725-7734. [PMID: 34674272 DOI: 10.1002/mp.15286] [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: 07/02/2021] [Revised: 09/19/2021] [Accepted: 10/05/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A two-layer cylinder (TLC) phantom was developed for simplifying film-based isocenter verification of linear accelerators in radiotherapy. METHODS AND MATERIALS The phantom mainly consists of two parts: (1) two nested solid cylinders between which a radiochromic film can be inserted and irradiated; (2) a tungsten ball supported by a thin rod and located at the phantom center for alignment with the mechanical isocenter. In practice, the phantom was first positioned by the room laser to align the tungsten ball to the mechanical isocenter of the linear accelerator. Then, a radiochromic film was precisely inserted into the gap between the two cylinders of the phantom and irradiated by beams with preset gantry and couch angles. Later the irradiated film was scanned and processed by an in-house developed analysis software. Finally, the offset of the radiation isocenter from the mechanical isocenter was determined by the built-in three-dimensional (3D) reconstruction algorithms. The accuracy of this method was evaluated by positioning the phantom with a known couch shift, then checking the residual error after couch shift correction. The reliability of this method was evaluated by comparing the calculated offset with the corresponding result determined by the traditional star-shot method. RESULTS For the accuracy test, the residual errors were -0.14 ± 0.03 mm, 0.05 ± 0.06 mm, and 0.05 ± 0.06 mm in the lateral, longitudinal, and vertical axes, respectively. For the reliability test, the differences between the calculated offset and the result determined by the star-shot method were -0.10 mm, 0.12 mm, and 0.12 mm in the lateral, longitudinal, and vertical axes, respectively. CONCLUSION The proposed method is able to reconstruct beams in 3D with one film, which is more time-saving and accurate. Additionally, with this design, the phantom positioning, film loading, beam delivery, and data analyzing are simpler. This phantom and analysis software provides an efficient and effective way to perform film-based isocenter verification of linear accelerators in radiotherapy.
Collapse
Affiliation(s)
- Zhiyue Song
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Hui Yan
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yingjie Xu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Jianrong Dai
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| |
Collapse
|
31
|
NanoDot™ OSLDs in verifying radiotherapy dose calculations in the presence of metal implants: A Monte Carlo assisted research. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
32
|
Effect of absorbed dose on post-irradiation coloration and interpretation of polymerization reaction in the Gafchromic EBT3 film. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
33
|
Evans T, Cooley J, Wagner M, Yu T, Zwart T. Demonstration of the FLASH Effect Within the Spread-out Bragg Peak After Abdominal Irradiation of Mice. Int J Part Ther 2021; 8:68-75. [PMID: 35530182 PMCID: PMC9009457 DOI: 10.14338/ijpt-20-00095] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 07/07/2021] [Indexed: 11/21/2022] Open
Abstract
Purpose The effects of FLASH-level dose rates delivered at the spread-out Bragg peak (SOBP) on normal tissue damage in mice were investigated. Materials and Methods Fifty nontumor-bearing mice received abdominal irradiation, 30 at FLASH dose rates (100 Gy/s) and 20 at conventional dose rates (0.1 Gy/s). Total dose values ranged from 10 to 19 Gy, delivered in a single spot by a synchrocyclotron proton therapy system. Centered on the abdomen, the collimated field delivered was an 11-mm diameter circle with a water-equivalent depth of 2.4 cm from entrance to distal 80% dose. A ridge filter was used to provide dose uniformity over the full 2.4-cm range. The spatial distribution was identical for both the FLASH and conventional deliveries. Results Overall survival and individual mouse weights were tracked for 21 days after the exposure date, and LD50 values were compared for the FLASH and conventional dose rate groups. Mice exposed to FLASH dose rates had a higher LD50 value as compared with mice exposed to conventional dose rates, with a dose-dependent improvement in survivability of 10% to 20%. The FLASH cohort also showed greater or equal percent population survival for each day of the study. Conclusion These results are preliminary confirmation of the potential for the combination of the advantages of the Bragg peak with the normal tissue sparing benefits of FLASH treatments. This experiment also confirms that pulsed synchrocyclotrons can be used for the purpose of FLASH research and treatment.
Collapse
|
34
|
Willoughby TR, Boczkowski A, Meeks SL, Bova FJ, Zeidan OA, Erhart K, Kelly P. Design and characterization of a prototype tertiary device for proton beam stereotactic radiosurgery. Biomed Phys Eng Express 2021; 7. [PMID: 34087816 DOI: 10.1088/2057-1976/ac086b] [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: 05/11/2021] [Accepted: 06/04/2021] [Indexed: 11/12/2022]
Abstract
Though potentially beneficial, proton beam stereotactic radiosurgery has not been adopted widely secondary to the technical challenge of safely delivering multiple focused beams of proton radiation. In this study, we describe the design and characterization of a proton beam stereotactic radiosurgery system that can be adopted by existing passive scattering systems. This system utilizes a helmet-like device in which patient-specific brass apertures required for final beam collimation are positioned on a scaffold that is separate from the treatment gantry. The proton snout is then fitted with a generic aperture to focus the primary proton beam onto the patient specific apertures that are in the helmet-like device. The patient-specific apertures can all be placed at the start of the treatment, thus treatment with multiple beams can be accomplished without the delay of switching the apertures. In this report we describe a prototype design of this collimation system and dosimetric testing to verify efficacy. Subsequently, we describe a custom 3D printing of a prototype device and report on overall localization accuracy using Winston-Lutz tests. Our results show that it is possible to develop an add-on device for proton beam radiosurgery that is safe and efficient and capable of wide adoption on existing proton delivery systems.
Collapse
Affiliation(s)
- T R Willoughby
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| | - A Boczkowski
- Department of Neurosurgery, University of Florida, Gainesville, FL, United States of America
| | - S L Meeks
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| | - F J Bova
- Department of Neurosurgery, University of Florida, Gainesville, FL, United States of America
| | - O A Zeidan
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| | - K Erhart
- DotDecimal, Sanford, FL, United States of America
| | - P Kelly
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| |
Collapse
|
35
|
Dumas JL, Dal R, Zefkili S, Robilliard M, Losa S, Birba I, Vu-Bezin J, Beddok A, Calugaru V, Dutertre G, De Marzi L. Addressing the dosimetric impact of bone cement and vertebroplasty in stereotactic body radiation therapy. Phys Med 2021; 85:42-49. [PMID: 33965740 DOI: 10.1016/j.ejmp.2021.04.023] [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: 12/08/2020] [Revised: 04/08/2021] [Accepted: 04/23/2021] [Indexed: 10/21/2022] Open
Abstract
PURPOSE Bone cement used for vertebroplasty can affect the accuracy on the dose calculation of the radiation therapy treatment. In addition the CT values of high density objects themselves can be misrepresented in kVCT images. The aim of our study is then to propose a streamlined approach for estimating the real density of cement implants used in stereotactic body radiation therapy. METHODS Several samples of cement were manufactured and irradiated in order to investigate the impact of their composition on the radiation dose. The validity of the CT conversion method for a range of photon energies was investigated, for the studied samples and on six patients. Calculations and measurements were carried out with various overridden densities and dose prediction algorithms (AXB with dose-to-medium reporting or AAA) in order to find the effective density override. RESULTS Relative dose differences of several percent were found between the dose measured and calculated downstream of the implant using an ion chamber and TPS or EPID dosimetry. If the correct density is assigned to the implant, calculations can provide clinically acceptable accuracy (gamma criteria of 3%/2 mm). The use of MV imaging significantly favors the attribution of a correct equivalent density to the implants compared to the use of kVCT images. CONCLUSION The porosity and relative density of the various studied implants vary significantly. Bone cement density estimations can be characterized using MV imaging or planar in vivo dosimetry, which could help determining whether errors in dose calculations are due to incorrect densities.
Collapse
Affiliation(s)
- Jean-Luc Dumas
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France.
| | - Romaric Dal
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Sofia Zefkili
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Magalie Robilliard
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Sandra Losa
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Imène Birba
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Jérémi Vu-Bezin
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Arnaud Beddok
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | - Valentin Calugaru
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France
| | | | - Ludovic De Marzi
- Institut Curie, PSL Research University, Radiation Oncology Department, Paris, France; Institut Curie, University Paris Saclay, PSL Research University, Inserm LITO, Orsay, France.
| |
Collapse
|
36
|
Development and dosimetric characterization of novel amide substituted diacetylene based radiochromic films for medical radiation dosimetry. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
37
|
Chaudhary RK, Kumar R, Sharma SD, Datta D. Computation of epistemic uncertainty due to limited data samples in small field dosimetry using Fuzzy Set Theory. Br J Radiol 2021; 94:20190561. [PMID: 33684311 DOI: 10.1259/bjr.20190561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To estimate the epistemic (or fuzzy) uncertainty, arising due to limited data samples in the measurement of the output factors (OFs) of the small fields using Fuzzy Set Theory (FST). METHODS EBT3 film samples of size 50 × 50 mm2 were used for the measurement of the OF of stereotactic radiosurgery (SRS) cones of size 4, 6, 7.5, 10, 12.5 and 15 mm diameter, normalized with respect to the output of 100 × 100 mm2 open field size. Three measurements were done per cone/field size. Red color channel was chosen for the dosimetry purpose, net optical density (NOD) was converted to the dose using non-linear relation. To estimate the epistemic uncertainty associated with the measured OFs due to limited number of data samples, a triangular fuzzy number (TFN) was assumed as the fuzziness in the dose delivered by the individual SRS cone/field. Uncertainty in the OF was estimated by applying the Fuzzy Vertex Method (FVM). The membership functions of the OF were constructed for each cone size and the nature of the uncertainty in the OF of the cones was expressed in the terms of its fuzziness. For the sake of completeness of the study, the statistical uncertainty involved in the procedure has also been calculated. RESULTS The statistical and fuzzy uncertainties in the measurement of OF of cones range from 3.28 to 6.25% and 2.58 to 5.44% respectively. The smallest cone of 4 mm has the largest values of statistical and fuzzy uncertainties. The membership functions of the OF for the studied cones were triangular in nature. CONCLUSION The epistemic uncertainty arising due to limited number of data samples holds a significant fraction of the prescribed dose, and therefore, should not be ignored in the total uncertainty estimation. ADVANCES IN KNOWLEDGE This study highlights the significance of epistemic component of measurement uncertainty arising out due to the insufficient/limited number of measurements of a quantity.
Collapse
Affiliation(s)
- Rahul Kumar Chaudhary
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Rajesh Kumar
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India
| | - S D Sharma
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
| | - D Datta
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
| |
Collapse
|
38
|
Evaluation of the surface dose for total body irradiation (TBI) technique with parallel-opposed anterior posterior geometry. JOURNAL OF RADIOTHERAPY IN PRACTICE 2021. [DOI: 10.1017/s1460396921000121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
Aim:
Total body irradiation (TBI) is an external radiotherapy technique in which the whole body including the superficial regions is required to receive the therapeutic dose. The purpose of this study is to evaluate the received surface dose during TBI technique.
Methods and materials:
The anterior/posterior (AP/PA) TBI was implemented with 18-MV photon beam at 312-cm treatment distance for human-like phantom. The GAFCHROMIC-EBT3 films were used for superficial dose measurements.
Results and discussion:
The percentage of surface-absorbed dose relative to the prescription point for 8 points of measurements was between 102·78–121·48% and 104·51–127·43% at 5 and 10 mm depth, respectively. In the chest wall region due to the presence of lung blocks, the absorbed dose was below the acceptable level, so an electron boost was required to increase the chest wall absorbed dose.
Conclusions:
According to the results, the implemented technique was able to deliver sufficient dose to the shallow surface of phantom’s body.
Collapse
|
39
|
FLASH Irradiation with Proton Beams: Beam Characteristics and Their Implications for Beam Diagnostics. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11052170] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
FLASH irradiations use dose-rates orders of magnitude higher than commonly used in patient treatments. Such irradiations have shown interesting normal tissue sparing in cell and animal experiments, and, as such, their potential application to clinical practice is being investigated. Clinical accelerators used in proton therapy facilities can potentially provide FLASH beams; therefore, the topic is of high interest in this field. However, a clear FLASH effect has so far been observed in presence of high dose rates (>40 Gy/s), high delivered dose (tens of Gy), and very short irradiation times (<300 ms). Fulfilling these requirements poses a serious challenge to the beam diagnostics system of clinical facilities. We will review the status and proposed solutions, from the point of view of the beam definitions for FLASH and their implications for beam diagnostics. We will devote particular attention to the topics of beam monitoring and control, as well as absolute dose measurements, since finding viable solutions in these two aspects will be of utmost importance to guarantee that the technique can be adopted quickly and safely in clinical practice.
Collapse
|
40
|
Kourkafas G, Bundesmann J, Fanselow T, Denker A, Ehrhardt VH, Gollrad J, Budach V, Weber A, Kociok N, Joussen AM, Heufelder J. FLASH proton irradiation setup with a modulator wheel for a single mouse eye. Med Phys 2021; 48:1839-1845. [PMID: 33480028 DOI: 10.1002/mp.14730] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/14/2020] [Accepted: 01/06/2021] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Recent studies indicate that FLASH irradiation, which involves ultra-high dose rates in a short time window (usually >40 Gy/s in <500 ms), might be equally efficient against tumors but less harmful to healthy tissues, compared to conventional irradiation with the same total dose. Aiming to verify the latter claim for ocular proton radiotherapy, in vivo experiments with mice are being carried out by Charité - Universitätsmedizin Berlin. This work presents the implemented setup for delivering FLASH proton radiation to a single eye of mice at the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB). MATERIALS AND METHODS The HZB cyclotron is tuned to provide a high-intensity 68 MeV focused proton beam. Outside the vacuum beamline, the protons hit a single scatterer, which also serves as range shifter, and a rotating modulator wheel, which produces a flat depth-dose distribution. Two transmission ionization chambers in between, read out by fast electronics, are used as dose monitors for triggering an in-vacuum beam shutter, which blocks the beam once the desired dose has been delivered. A collimating aperture shapes the radiation field at the isocenter, which is measured by a radioluminescent screen and a CCD camera. At the same position, a parallel-plate ionization chamber of type Advanced Markus® is used for absolute dosimetry and characterization of the spread-out Bragg peak inside a water phantom. A thin-foil mirror of adjustable tilt in the beam path assists the correct alignment of the target through side illumination. Radiochromic films of type EBT3 are used to supplement the dosimetry and assist the alignment. RESULTS A dose rate of 75 Gy/s has been measured, delivering within 200 ms 15 Gy (RBE) with a reproducibility better than ±1%. A depth-dose curve with a range of 5.2 mm in water, 0.9 mm distal fall-off (90%-10%), and ±2.5% ripple has been demonstrated, with a PTV of 6.3 mm diameter, 1.7 mm lateral penumbra (90%-10%), 8% uniformity, and 3% symmetry. CONCLUSIONS The implemented setup is able to accommodate ocular irradiation of narcotized mice with protons, targeting selectively the left or the right eye, under conventional and FLASH conditions. Switching between these two modes can be done within half an hour, including the calibration of the dose monitors and the verification of the dose delivery. Further upgrades are planned after the completion of the on-going experiment.
Collapse
Affiliation(s)
- Georgios Kourkafas
- Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Berlin, Germany
| | - Juergen Bundesmann
- Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Berlin, Germany
| | - Timo Fanselow
- Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Berlin, Germany
| | - Andrea Denker
- Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Berlin, Germany.,Beuth University of Applied Sciences Berlin, Berlin, Germany
| | - Vincent Henrique Ehrhardt
- Department of Radiation Oncology and Radiotherapy, Charité- Universitätsmedizin Berlin, Berlin, Germany
| | - Johannes Gollrad
- Department of Radiation Oncology and Radiotherapy, Charité- Universitätsmedizin Berlin, Berlin, Germany
| | - Volker Budach
- Department of Radiation Oncology and Radiotherapy, Charité- Universitätsmedizin Berlin, Berlin, Germany
| | - Andreas Weber
- Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,BerlinProtonen am HZB, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Norbert Kociok
- Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Antonia M Joussen
- Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jens Heufelder
- Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,BerlinProtonen am HZB, Charité - Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
41
|
Li C, Lin JF, Yeh HL. Dosimetric characteristics of accelerated partial breast irradiation by interstitial multicatheter brachytherapy with intraoperative free-hand implantation in the treatment of early breast cancer. J Appl Clin Med Phys 2021; 22:27-34. [PMID: 33626212 PMCID: PMC7984496 DOI: 10.1002/acm2.13169] [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] [Received: 11/11/2020] [Revised: 12/10/2020] [Accepted: 12/25/2020] [Indexed: 12/03/2022] Open
Abstract
Introduction The aim of this study is to evaluate the characteristics of the dosimetry and the skin dose of interstitial brachytherapy by the use of the free‐hand implantation technique toward the treatment of early breast cancer. Materials & Methods Seventeen patients diagnosed with early breast cancer were selected for the study. The implantation of the catheters for postoperative interstitial brachytherapy was performed using the free‐hand technique. The total tumor dose to the tumor cavity plus 2 cm margin was 3400 cGy, twice daily for 10 fractions in 5 days. The dosage to the target and the organ at risk (OAR) were recorded for analysis. The skin dose of the patient and the phantom were measured with Gafchromic film (EBT3) and the results were compared with the skin dose calculated by the brachytherapy treatment planning system. Results The median conformal index is 94% (range 89%–99%), and the median homogeneity index is 71%. The median skin dose measured from the skin of the patients was 20.1% lower than the skin dose calculated from the treatment planning system and consistent with the phantom surface measurement experiment. There were no grade 3 or above acute toxicity recorded. Conclusions Interstitial brachytherapy by the use of the free‐hand implantation technique for early breast cancer is feasible and avoids the need for a second surgical intervention. The calculated skin dose was overestimated by at least 20%. The results of this study may help in building a modification model for the prediction of skin toxicity in any future study.
Collapse
Affiliation(s)
- Chuan Li
- Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Jia-Fu Lin
- Department of Radiation Physics, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Hui Ling Yeh
- Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan
| |
Collapse
|
42
|
Manufacturing and evaluation of multi-channel cylinder applicator with 3D printing technology. J Contemp Brachytherapy 2021; 13:80-90. [PMID: 34025740 PMCID: PMC8117717 DOI: 10.5114/jcb.2021.103590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 12/14/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose This study was designed to assess dosimetric characteristics of 3D-printed personalized multi-channel cylinder applicator (MCCA). Material and methods UnionTech RS Pro 600 (UnionTech, Inc., Shanghai, China) 3D printer was used for manufacturing MCCA. The geometry of MCCA was designed with Fusion 360 v.2.0.5827 (Autodesk, Inc.) software. The designed file was exported to Meshmixer v.3.5 (Autodesk, Inc.) to create three-dimensional model in stereolithography (STL) file format, which is the common file format for inputting data to 3D printers. We used high-temp resin, FLHTAM02 model (Formlabs Inc., MA, USA), as material in 3D printing process. This resin model has good resistance to high temperature and compatibility with various solvents. We created a simple cubic shape phantom for dosimetric evaluation of the applicator with Gafchromic EBT3 films. Also, Monte Carlo method was applied to simulate MCCA in the same configuration as in experimental test. Results The mean ± standard deviation (SD) difference between measured and calculated doses in treatment planning system (TPS) for all control points was 0.0860 ±0.0393 Gy, corresponding to 4.01 ±1.21%. The mean ±SD difference between doses calculated by Monte Carlo simulation and TPS for all control points was 0.0996 ±0.0471 Gy, corresponding to 4.58 ±1.05%. The mean ±SD of dose difference between film measurement and Monte Carlo simulation for all control points was 0.0136 ±0.0200 Gy, corresponding to 0.60 ±0.69%. P-value for dose difference between film measurement and TPS, Monte Carlo and TPS, and film measurement and Monte Carlo were 0.7, 0.66, and 0.95, respectively. Conclusions Dosimetric results and mechanical accuracy of MCCA show that high-temp resin with SLA 3D printing technique can be used for producing patient-specific MCCA in brachytherapy.
Collapse
|
43
|
Santos T, Ventura T, Lopes MDC. A review on radiochromic film dosimetry for dose verification in high energy photon beams. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109217] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
44
|
Shin D, Yoon M, Moon S, Jo Y, Seo J. Inter-fractional entrance dose monitoring as quality assurance using Gafchromic EBT3 film. J Cancer Res Ther 2021; 18:1152-1158. [DOI: 10.4103/jcrt.jcrt_8_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
45
|
Chaudhary RK, Pathan M, Kumar R, Sharma SD, Sapra BK. Probability Distribution of Pixel Intensities of EBT3 Films and its Application in the Correction of Uncertainty Budget. J Med Phys 2021; 46:26-32. [PMID: 34267486 PMCID: PMC8240913 DOI: 10.4103/jmp.jmp_94_20] [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] [Received: 10/05/2020] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND AND AIM Modern radiotherapy modalities, such as Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy involve complex dose delivery. The dose delivery is complex as it involves beam modulation, hence, manual dose calculations for these techniques are not possible. Film dosimetry is commonly used method of dose verification for these modalities because of the advantages associated with it. The quantification of uncertainty associated with a film dosimetry system under clinical use becomes important for accurate dosimetry. The spread in the distribution of the pixel values (PV) of the irradiated film contributes to the uncertainty. The probability distribution (PD) of the PV was studied for the clinical photon beam energies of 6, 10, and 15 MV. METHODS AND MATERIALS Gafchromic EBT3 film and EPSON 10000XL flatbed scanner were used for this purpose and using the resulting PD, the uncertainty budgets for these energies in the red, green and blue color channels were estimated. RESULTS The PV of exposed films for the energies studied follows t-distribution, the sum of the squares of the deviation of the measured data from the fitted value was of the order of 10-7, this indicates the goodness of fit. The "t" value corrected combined standard uncertainty (CSU) at 1σ confidence level for exposed film and dose measurement at 200 cGy were 1.42%, 1.48%, and 1.63% and 1.99%, 3.23%, and 5.08% for 6, 10, and 15 MV energies, respectively, in the red colour channel. CONCLUSION In the case of the limited number of measurements of a quantity, the SU values must be corrected using the "t" value to get the correct CSU.
Collapse
Affiliation(s)
- Rahul Kumar Chaudhary
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Munir Pathan
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Rajesh Kumar
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - S. D. Sharma
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - B. K. Sapra
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Mumbai, Maharashtra, India
| |
Collapse
|
46
|
Santos J, Silva S, Sarmento S. Optimized method for in vivo dosimetry with small films in pelvic IOERT for rectal cancer. Phys Med 2020; 81:20-30. [PMID: 33338728 DOI: 10.1016/j.ejmp.2020.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 11/09/2020] [Accepted: 11/15/2020] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Intra-Operative Electron Radiation Therapy (IOERT) is used to treat rectal cancer at our institution, and in vivo measurements with Gafchromic EBT3® films were introduced as quality assurance. The purpose of this work was to quantify the uncertainties associated with digitization of very small EBT3 films irradiated simultaneously, in order to optimize in vivo dosimetry for IOERT. METHODS Film samples of different sizes - M1 (5×5cm2), M2 (1.5×1.5 cm2), M3 (1.0×1.5 cm2) and M4 (0.75×1.5 cm2) - were used to quantify typical variations (uncertainties) due to scanner fluctuations, misalignment, film inhomogeneity, long-term effect of film cutting, small rotations, film curling, edge effects and the influence of opaque templates. Fitting functions and temporal validity of sensitometric curves were also assessed. RESULTS Film curling, intra-film variability and scanner fluctuations are important effects that need to be minimized or considered in the uncertainty budget. Small rotations, misalignments and film cutting have little or no influence on the readings. Most fitting functions perform well, but the quantity used for dose quantification determines over- or under-valuation of dose in the long term. Edge effects and the influence of opaque templates need to be well understood, to allow optimization of methodology to the intended purpose. CONCLUSION The proposed method allows practical and simultaneous digitization of up to ten small irradiated film samples, with an experimental uncertainty of 1%.
Collapse
Affiliation(s)
- Joana Santos
- Physics and Astronomy Department, Faculty of Sciences, University of Porto, Portugal; Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Sofia Silva
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal; Medical Physics Service, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Sandra Sarmento
- Management, Outcomes Research and Economics in Healthcare Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal; Medical Physics Service, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
| |
Collapse
|
47
|
Esplen N, Mendonca MS, Bazalova-Carter M. Physics and biology of ultrahigh dose-rate (FLASH) radiotherapy: a topical review. Phys Med Biol 2020; 65:23TR03. [PMID: 32721941 DOI: 10.1088/1361-6560/abaa28] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ultrahigh dose-rate radiotherapy (RT), or 'FLASH' therapy, has gained significant momentum following various in vivo studies published since 2014 which have demonstrated a reduction in normal tissue toxicity and similar tumor control for FLASH-RT when compared with conventional dose-rate RT. Subsequent studies have sought to investigate the potential for FLASH normal tissue protection and the literature has been since been inundated with publications on FLASH therapies. Today, FLASH-RT is considered by some as having the potential to 'revolutionize radiotherapy'. FLASH-RT is considered by some as having the potential to 'revolutionize radiotherapy'. The goal of this review article is to present the current state of this intriguing RT technique and to review existing publications on FLASH-RT in terms of its physical and biological aspects. In the physics section, the current landscape of ultrahigh dose-rate radiation delivery and dosimetry is presented. Specifically, electron, photon and proton radiation sources capable of delivering ultrahigh dose-rates along with their beam delivery parameters are thoroughly discussed. Additionally, the benefits and drawbacks of radiation detectors suitable for dosimetry in FLASH-RT are presented. The biology section comprises a summary of pioneering in vitro ultrahigh dose-rate studies performed in the 1960s and early 1970s and continues with a summary of the recent literature investigating normal and tumor tissue responses in electron, photon and proton beams. The section is concluded with possible mechanistic explanations of the FLASH normal-tissue protection effect (FLASH effect). Finally, challenges associated with clinical translation of FLASH-RT and its future prospects are critically discussed; specifically, proposed treatment machines and publications on treatment planning for FLASH-RT are reviewed.
Collapse
Affiliation(s)
- Nolan Esplen
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | | | | |
Collapse
|
48
|
Robinson SM, Esplen N, Wells D, Bazalova-Carter M. Monte Carlo simulations of EBT3 film dose deposition for percentage depth dose (PDD) curve evaluation. J Appl Clin Med Phys 2020; 21:314-324. [PMID: 33155768 PMCID: PMC7769387 DOI: 10.1002/acm2.13078] [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: 05/04/2020] [Revised: 08/04/2020] [Accepted: 10/05/2020] [Indexed: 02/04/2023] Open
Abstract
Purpose To use Monte Carlo (MC) calculations to evaluate the effects of Gafchromic EBT3 film orientation on percentage depth dose (PDD) curves. Methods Dose deposition in films placed in a water phantom, and oriented either parallel or perpendicular with respect to beam axis, were simulated with MC and compared to PDDs scored in a homogenous water phantom. The effects of introducing 0.01–1.00 mm air gaps on each side of the film as well as a small 1°‐3° tilt for film placed in parallel orientation were studied. PDDs scored based on two published EBT3 film compositions were compared. Three photon beam energies of 120 kVp, 220 kVp, and 6 MV and three field sizes between 1 × 1 and 5 × 5 cm2 were considered. Experimental PDDs for a 6‐MV 3 × 3 cm2 beam were acquired. Results PDD curves for films in perpendicular orientation more closely agreed to water PDDs than films placed in parallel orientation. The maximum difference between film and water PDD for films in parallel orientation was −12.9% for the 220 kVp beam. For the perpendicular film orientation, the maximum difference decreased to 5.7% for the 120 kVp beam. The inclusion of an air gap had the largest effect on the 6‐MV 1 × 1 cm2 beam, for which the dose in the buildup region was underestimated by 21.2% compared to the simulation with no air gap. A 2° film tilt decreased the difference between the parallel film and homogeneous water phantom PDDs from −5.0% to −0.5% for the 6 MV 3 × 3 cm2 beam. The “newer” EBT3 film composition resulted in larger PDD discrepancies than the previous composition. Experimental film data qualitatively agreed with MC simulations. Conclusions PDD measurements with films should either be performed with film in perpendicular orientation to the beam axis or in parallel orientation with a ~ 2º tilt and no air gaps.
Collapse
Affiliation(s)
- Spencer M Robinson
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | - Nolan Esplen
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | - Derek Wells
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada.,BC Cancer Vancouver Island Centre, Victoria, BC, Canada
| | | |
Collapse
|
49
|
Niroomand‐Rad A, Chiu‐Tsao S, Grams MP, Lewis DF, Soares CG, Van Battum LJ, Das IJ, Trichter S, Kissick MW, Massillon‐JL G, Alvarez PE, Chan MF. Report of AAPM Task Group 235 Radiochromic Film Dosimetry: An Update to TG‐55. Med Phys 2020; 47:5986-6025. [DOI: 10.1002/mp.14497] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Affiliation(s)
| | | | | | | | | | | | - Indra J. Das
- Radiation Oncology Northwestern University Memorial Hospital Chicago IL USA
| | - Samuel Trichter
- New York‐Presbyterian HospitalWeill Cornell Medical Center New York NY USA
| | | | - Guerda Massillon‐JL
- Instituto de Fisica Universidad Nacional Autonoma de Mexico Mexico City Mexico
| | - Paola E. Alvarez
- Imaging and Radiation Oncology Core MD Anderson Cancer Center Houston TX USA
| | - Maria F. Chan
- Memorial Sloan Kettering Cancer Center Basking Ridge NJ USA
| |
Collapse
|
50
|
Darafsheh A, Zhao T, Khan R. Spectroscopic analysis of irradiated radiochromic EBT-XD films in proton and photon beams. ACTA ACUST UNITED AC 2020; 65:205002. [DOI: 10.1088/1361-6560/aba28e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|