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Lankinen L, Kulmala A, Lehtomäki J, Harju A. The delivery assessment for small targets on Halcyon radiotherapy system - Measured and calculated dose comparison. J Appl Clin Med Phys 2024; 25:e14407. [PMID: 38775807 PMCID: PMC11163489 DOI: 10.1002/acm2.14407] [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: 12/13/2023] [Revised: 03/18/2024] [Accepted: 04/01/2024] [Indexed: 06/11/2024] Open
Abstract
BACKGROUND With the ever-increasing requirements of accuracy and personalization of radiotherapy treatments, stereotactic radiotherapy (SRT) with volumetric modulated arc therapy (VMAT) on O-ring Halcyon radiotherapy system could potentially provide a fast, safe, and feasible treatment option. PURPOSE The purpose of this study was to assess the delivery of Halcyon VMAT plans for small targets. METHODS Well-defined VMAT-SRT plans were created on Halcyon radiotherapy system with the stacked and staggered dual-layer MLC design for the film measurement set-up and the target sizes and shapes designed to emulate the targets of the stereotactic treatments. The planar dose distributions were acquired with film measurements and compared to a current clinical reference dose calculation with AcurosXB (v18.0, Varian Medical Systems) and to Monte Carlo simulations. With the collapsed arc versions of the VMAT-SRT plans, the uncertainty in dose delivery due to the multileaf collimator (MLC) without the gantry rotation could be separated and analyzed. RESULTS The target size was mainly limited by the resolution originated from the design of the MLC leaves. The results of the collapsed arc versions of the plans show good consistency among measured, calculated, and simulated dose distributions. With the full VMAT plans, the agreement between calculated and simulated dose distributions was consistent with the collapsed arc versions. The measured dose distribution agreed with the calculated and simulated dose distributions within the target regions, but considerable local differences were observed in the margins of the target. The largest differences located in the steep gradient regions presumably originating from the deviation of the isocenter. CONCLUSIONS The potential of the Halcyon radiotherapy system for VMAT-SRT delivery was evaluated and the study revealed valuable insights on the machine characteristics with the delivery.
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Affiliation(s)
- Linda Lankinen
- Varian Medical Systems, a Siemens Healthineers CompanyHelsinkiFinland
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Antti Kulmala
- Clinical Research Institute HUCH Ltd.HelsinkiFinland
| | - Jouko Lehtomäki
- Varian Medical Systems, a Siemens Healthineers CompanyHelsinkiFinland
| | - Ari Harju
- Varian Medical Systems, a Siemens Healthineers CompanyHelsinkiFinland
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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.
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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
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Rodrigues-Machado FC, Janitz E, Bernard S, Bekerat H, McEwen M, Renaud J, Enger SA, Childress L, Sankey JC. Radiation hardness of open Fabry-Pérot microcavities. OPTICS EXPRESS 2024; 32:17189-17196. [PMID: 38858908 DOI: 10.1364/oe.522332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/07/2024] [Indexed: 06/12/2024]
Abstract
High-finesse microcavities offer a platform for compact, high-precision sensing by employing high-reflectivity, low-loss mirrors to create effective optical path lengths that are orders of magnitude larger than the device geometry. Here, we investigate the radiation hardness of Fabry-Pérot microcavities formed from dielectric mirrors deposited on the tips of optical fibers. The microcavities are irradiated under both conventional (∼ 0.1 Gy/s) and ultrahigh (FLASH, ∼ 20 Gy/s) radiotherapy dose rates. Within our measurement sensitivity of ∼ 40 ppm loss, we observe no degradation in the mirror absorption after irradiation with over 300 Gy accumulated dose. This result highlights the excellent radiation hardness of the dielectric mirrors forming the cavities, enabling new optics-based, real-time, in-vivo, tissue-equivalent radiation dosimeters with ∼ 10 micron spatial resolution (our motivation), as well as other applications in high-radiation environments.
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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.
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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
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Chan MF, Park J, Aydin R, Lim SB. Technical note: Energy dependence of the Gafchromic EBT4 film: Dose-response curves for 70 kV, 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV x-ray beams. Med Phys 2023; 50:3738-3745. [PMID: 36695666 PMCID: PMC10635410 DOI: 10.1002/mp.16240] [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: 10/17/2022] [Revised: 12/30/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND EBT4 was newly released for radiotherapy quality assurance to improve the signal-to-noise ratio in radiochromic film dosimetry. It is important to know its dose-response characteristics before its use in the clinic. PURPOSE This study aims to investigate and compare the dose-response curves of the Gafchromic EBT4 film for megavoltage and kilovoltage x-ray beams with different dose levels, scanning spatial resolutions, and sizes of region of interest (ROI). METHODS EBT4 film (Lot#07052201) calibration strips (3.5 × 20 cm2 ) were exposed to a 10×10 cm2 open field at doses of 0, 63, 125, 500, 750, 1000 cGy using 6 MV photon beam. EBT4 film strips from the same lot were then exposed to each x-ray beam (6 MV, 6 MV FFF, 10 MV FFF, 15 MV, and 70 kV) at six dose values (50, 100, 300, 600, 800, 1000 cGy). A full sheet (25 × 20 cm2 ) of EBT4 film was irradiated at each energy with 300 cGy for profile comparison with the treatment planning calculation. At two different spatial resolutions of 72 and 300 dpi, each film piece was scanned three consecutive times in the center of an Epson 10000XL flatbed scanner in 48-bit color. The scanned images were analyzed using FilmQA Pro. For each scanned image, an ROI of 2 × 2 cm2 at the field center was selected to obtain the average pixel value with its standard deviation in the ROI. An additional ROI of 1 cm diameter circle was also used to evaluate the impact of ROI shape and size, especially for FFF beams. The dose value, average dose-response value, and associated uncertainty were determined for each energy and relative responses were analyzed. The Student's t-test was performed to evaluate the statistical significance of the dose-response values with different color channels, ROI shapes, and spatial resolutions. RESULTS The dose-response curves for the five x-ray energies were compared in three color channels. Weak energy dependence was found among the megavoltage beams. No significant differences (average ∼1.1%) were observed for all doses in this study among 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV beams, regardless of spatial resolution and color channel. However, a statistically significant difference in dose-response was observed up to 12% between 70 kV and 6 MV beams. CONCLUSIONS The dose-response curves for Gafchromic EBT4 films were nearly independent of the energy of the photon beams among 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV. For very low-energy photons (e.g., 70 kV), a separate calibration from the same low-energy x-ray is necessary.
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Affiliation(s)
- Maria F. Chan
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Jeonghoon Park
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | | | - Seng-Boh Lim
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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Laakkonen L, Lehtomäki J, Cahill A, Constantin M, Kulmala A, Harju A. Monte Carlo modeling of Halcyon and Ethos radiotherapy beam using CAD geometry: validation and IAEA-compliant phase space. Phys Med Biol 2023; 68. [PMID: 36657172 DOI: 10.1088/1361-6560/acb4d9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/19/2023] [Indexed: 01/20/2023]
Abstract
Objective.A Monte Carlo (MC) model of a Halcyon and Ethos (Varian Medical Systems, a Siemens Healthineers Company) radiotherapy beam was validated and field-independent phase space (PHSP) files were recorded above the dual-layer multileaf collimators (MLC).Approach.The treatment head geometry was modeled according to engineering drawings and the dual-layer MLC was imported from CAD (computer-aided design) files. The information for the incident electron beam was achieved from an iterative electromagnetic solver. The validation of the model was performed by comparing the dose delivered by the square MLC fields as well as complex field measurements.Main results.An electron phase space was generated from linac simulations and achieved improved MC results. The output factors for square fields were within 1% and the largest differences of 5% were found in the build-up region of PDDs and the penumbra region of profiles. With the more complicated MLC-shaped field (Fishbone), the largest differences of up to 8% were found in the MLC leaf tip region due to the uncertainty of the MLC positioning and the mechanical leaf gap value. The impact of the collimator rotation on the PHSP solution has been assessed with both small and large fields, confirming negligible effects on in-field and out-of-field dose distributions.Significance.A computational model of the Halcyon and Ethos radiotherapy beam with a high accuracy implementation of the MLC was shown to be able to reproduce the radiation beam characteristics with square fields and more complex MLC-shaped fields. The field-independent PHSP files that were produced can be used as an accurate treatment head model above the MLC, and reduce the time to simulate particle transport through treatment head components.
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Affiliation(s)
- Linda Laakkonen
- Varian Medical Systems, a Siemens Healthineers Company, Helsinki, Finland.,Department of Physics, University of Helsinki, Finland
| | - Jouko Lehtomäki
- Varian Medical Systems, a Siemens Healthineers Company, Helsinki, Finland
| | - Alexander Cahill
- Varian Medical Systems, a Siemens Healthineers Company, Helsinki, Finland
| | | | - Antti Kulmala
- Clinical Research Institute HUCH Ltd., Helsinki, Finland
| | - Ari Harju
- Varian Medical Systems, a Siemens Healthineers Company, Helsinki, Finland
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Strolin S, Paolani G, Santoro M, Cercenelli L, Bortolani B, Ammendolia I, Cammelli S, Cicoria G, Win PW, Morganti AG, Marcelli E, Strigari L. Improving total body irradiation with a dedicated couch and 3D-printed patient-specific lung blocks: A feasibility study. Front Oncol 2023; 12:1046168. [PMID: 36741733 PMCID: PMC9893493 DOI: 10.3389/fonc.2022.1046168] [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: 09/16/2022] [Accepted: 11/16/2022] [Indexed: 01/20/2023] Open
Abstract
Introduction Total body irradiation (TBI) is an important component of the conditioning regimen in patients undergoing hematopoietic stem cell transplants. TBI is used in very few patients and therefore it is generally delivered with standard linear accelerators (LINACs) and not with dedicated devices. Severe pulmonary toxicity is the most common adverse effect after TBI, and patient-specific lead blocks are used to reduce mean lung dose. In this context, online treatment setup is crucial to achieve precise positioning of the lung blocks. Therefore, in this study we aim to report our experience at generating 3D-printed patient-specific lung blocks and coupling a dedicated couch (with an integrated onboard image device) with a modern LINAC for TBI treatment. Material and methods TBI was planned and delivered (2Gy/fraction given twice a day, over 3 days) to 15 patients. Online images, to be compared with planned digitally reconstructed radiographies, were acquired with the couch-dedicated Electronic Portal Imaging Device (EPID) panel and imported in the iView software using a homemade Graphical User Interface (GUI). In vivo dosimetry, using Metal-Oxide Field-Effect Transistors (MOSFETs), was used to assess the setup reproducibility in both supine and prone positions. Results 3D printing of lung blocks was feasible for all planned patients using a stereolithography 3D printer with a build volume of 14.5×14.5×17.5 cm3. The number of required pre-TBI EPID-images generally decreases after the first fraction. In patient-specific quality assurance, the difference between measured and calculated dose was generally<2%. The MOSFET measurements reproducibility along each treatment and patient was 2.7%, in average. Conclusion The TBI technique was successfully implemented, demonstrating that our approach is feasible, flexible, and cost-effective. The use of 3D-printed patient-specific lung blocks have the potential to personalize TBI treatment and to refine the shape of the blocks before delivery, making them extremely versatile.
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Affiliation(s)
- Silvia Strolin
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Giulia Paolani
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy,*Correspondence: Giulia Paolani, ; Lidia Strigari,
| | - Miriam Santoro
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Laura Cercenelli
- eDIMES Lab-Laboratory of Bioengineering, Department of Experimental Diagnostic and Specialty Medicine, (DIMES), Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Barbara Bortolani
- eDIMES Lab-Laboratory of Bioengineering, Department of Experimental Diagnostic and Specialty Medicine, (DIMES), Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Ilario Ammendolia
- Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Silvia Cammelli
- Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy,Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Gianfranco Cicoria
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Phyo Wai Win
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Alessio G. Morganti
- Radiation Oncology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy,Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Emanuela Marcelli
- eDIMES Lab-Laboratory of Bioengineering, Department of Experimental Diagnostic and Specialty Medicine, (DIMES), Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Lidia Strigari
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy,*Correspondence: Giulia Paolani, ; Lidia Strigari,
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Renaud J, Muir B. Assessing the accuracy of electronic portal imaging device (EPID)-based dosimetry: II. Evaluation of a dosimetric uncertainty budget and development of a new film-in-EPID absorbed dose calibration methodology. Med Phys 2021; 49:1238-1247. [PMID: 34954834 DOI: 10.1002/mp.15425] [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: 11/22/2021] [Accepted: 12/12/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The aim of this study is to reduce the uncertainty associated with determining dose-to-water using an amorphous silicon electronic portal imaging detector (EPID) under reference conditions by developing a direct calibration formalism based on radiochromic film measurements made within the EPID panel and detailed Monte Carlo simulations. To our knowledge, this is the first EPID-based dosimetry study reporting an uncertainty budget . METHODS Pixel sensitivity and relative off-axis response was mapped by simultaneously irradiating film contained within the imager panel and acquiring an EPID image set. The detector panel was disassembled for the purpose of modeling the EPID in detail using the EGSnrc DOSXYZnrc usercode, which was in turn used to calculate dose-to-film in EPID to dose-to-water in water conversion factors . RESULTS A direct comparison of the two correction methodologies investigated in this work, the previously established empirical method and the proposed simultaneous measurement approach involving in-EPID film dosimetry, produced an agreement with an RMS deviation of 1.4 % overall. A combined standard relative uncertainty of 3.3 % (k = 1) was estimated for the determination of absorbed dose to water at the position of the EPID using the proposed calibration methodology . CONCLUSIONS This work describes a direct method of calibrating EPID response in terms of absorbed dose to water requiring fewer measurements than other empirical approaches, and without 2D spatial interpolation of correction factors. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- James Renaud
- Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Bryan Muir
- Metrology Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
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Li J, Zhang X, Pan Y, Zhuang H, Wang J, Yang R. Assessment of Delivery Quality Assurance for Stereotactic Radiosurgery With Cyberknife. Front Oncol 2021; 11:751922. [PMID: 34868957 PMCID: PMC8635503 DOI: 10.3389/fonc.2021.751922] [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: 08/02/2021] [Accepted: 10/26/2021] [Indexed: 11/25/2022] Open
Abstract
Purpose The purpose of this study is to establish and assess a practical delivery quality assurance method for stereotactic radiosurgery with Cyberknife by analyzing the geometric and dosimetric accuracies obtained using a PTW31016 PinPoint ionization chamber and EBT3 films. Moreover, this study also explores the relationship between the parameters of plan complexity, target volume, and deliverability parameters and provides a valuable reference for improving plan optimization and validation. Methods One hundred fifty cases of delivery quality assurance plans were performed on Cyberknife to assess point dose and planar dose distribution, respectively, using a PTW31016 PinPoint ionization chamber and Gafchromic EBT3 films. The measured chamber doses were compared with the planned mean doses in the sensitive volume of the chamber, and the measured planar doses were compared with the calculated dose distribution using gamma index analysis. The gamma passing rates were evaluated using the criteria of 3%/1 mm and 2%/2 mm. The statistical significance of the correlations between the complexity metrics, target volume, and the gamma passing rate were analyzed using Spearman’s rank correlation coefficient. Results For point dose comparison, the averaged dose differences (± standard deviations) were 1.6 ± 0.73% for all the cases. For planar dose distribution, the mean gamma passing rate for 3%/1 mm, and 2%/2 mm evaluation criteria were 94.26% ± 1.89%, and 93.86% ± 2.16%, respectively. The gamma passing rates were higher than 90% for all the delivery quality assurance plans with the criteria of 3%/1 mm and 2%/2 mm. The difference in point dose was lowly correlated with volume of PTV, number of beams, and treatment time for 150 DQA plans, and highly correlated with volume of PTV for 18 DQA plans of small target. DQA gamma passing rate (2%/2 mm) was a moderate significant correlation for the number of nodes, number of beams and treatment time, and a low correlation with MU. Conclusion PTW31016 PinPoint ionization chamber and EBT3 film can be used for routine Cyberknife delivery quality assurance. The point dose difference should be within 3%. The gamma passing rate should be higher than 90% for the criteria of 3%/1 mm and 2%/2 mm. In addition, the plan complexity and PTV volume were found to have some influence on the plan deliverability.
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Affiliation(s)
- Jun Li
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Xile Zhang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Yuxi Pan
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Hongqing Zhuang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Junjie Wang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Ruijie Yang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
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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.
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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
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11
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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]
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12
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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%.
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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.
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13
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Chang KH, Lee YH, Park BH, Han MC, Kim J, Kim H, Cho MS, Kang H, Lee H, Kim DW, Park K, Cho J, Kim YB, Kim JS, Hong CS. Statistical Analysis of Treatment Planning Parameters for Prediction of Delivery Quality Assurance Failure for Helical Tomotherapy. Technol Cancer Res Treat 2020; 19:1533033820979692. [PMID: 33302821 PMCID: PMC7734483 DOI: 10.1177/1533033820979692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Purpose: This study aimed to investigate the parameters with a significant impact on delivery quality assurance (DQA) failure and analyze the planning parameters as possible predictors of DQA failure for helical tomotherapy. Methods: In total, 212 patients who passed or failed DQA measurements were retrospectively included in this study. Brain (n = 43), head and neck (n = 37), spinal (n = 12), prostate (n = 36), rectal (n = 36), pelvis (n = 13), cranial spinal irradiation and a treatment field including lymph nodes (n = 24), and other types of cancer (n = 11) were selected. The correlation between DQA results and treatment planning parameters were analyzed using logistic regression analysis. Receiver operating characteristic (ROC) curves, areas under the curves (AUCs), and the Classification and Regression Tree (CART) algorithm were used to analyze treatment planning parameters as possible predictors for DQA failure. Results: The AUC for leaf open time (LOT) was 0.70, and its cut-off point was approximately 30%. The ROC curve for the predicted probability calculated when the multivariate variable model was applied showed an AUC of 0.815. We confirmed that total monitor units, total dose, and LOT were significant predictors for DQA failure using the CART. Conclusions: The probability of DQA failure was higher when the percentage of LOT below 100 ms was higher than 30%. The percentage of LOT below 100 ms should be considered in the treatment planning process. The findings from this study may assist in the prediction of DQA failure in the future.
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Affiliation(s)
- Kyung Hwan Chang
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Young Hyun Lee
- Eretec Inc. 401, Simin-daero, Dongan-gu, Anyang-si, Gyeonggi-do, South Korea
| | - Byung Hun Park
- Eretec Inc. 401, Simin-daero, Dongan-gu, Anyang-si, Gyeonggi-do, South Korea
| | - Min Cheol Han
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Jihun Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Hojin Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Min-Seok Cho
- Department of Radiation Oncology, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, South Korea
| | - Hyokyeong Kang
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Ho Lee
- Department of Radiation Oncology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Dong Wook Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Kwangwoo Park
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Jaeho Cho
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Yong Bae Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Chae-Seon Hong
- Department of Radiation Oncology, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, South Korea
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14
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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.
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Affiliation(s)
- Nolan Esplen
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
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15
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Rodríguez C, López-Fernández A, García-Pinto D. A new approach to radiochromic film dosimetry based on non-local means. Phys Med Biol 2020; 65:225019. [PMID: 33200749 DOI: 10.1088/1361-6560/abb71b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Radiochromic film in conjunction with flatbed scanners are frequently employed as dosimeters for advanced techniques in radiotherapy. Their strengths are as follows: light element composition, low energy dependence, near biological tissue equivalence and high spatial resolution. However, they have some weaknesses as well: non-uniformities, read out noise, and scanning artifacts. Several processing protocols have been proposed intending to correct the perturbations these weaknesses produce. The aim of this paper is to present a new processing protocol for radiochromic film dosimetry based on a non-local means denoising algorithm. Three dose distributions of open square fields and a spatial combination of these fields using different angles of incidence and monitor units have been employed to validate the protocol. The dose distributions are traceable to ionization chamber measurements. Additionally, a real dose distribution of a treatment was used to simulate scanning data with noise and scanning lateral artifact, and to study how the protocol behaves under these perturbations. The same measured raw data have been processed by means of an implementation of the multichannel protocol (multigaussian method). It has been found that the proposed protocol reduces dose uncertainty even though it uses fewer scans than the multichannel protocol.
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Affiliation(s)
- César Rodríguez
- Medical Physics and Radiation Protection Service, Fuenlabrada University Hospital, Fuenlabrada, Spain. Medical Physics, Radiology Department, Complutense University, Madrid, Spain
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Asfia A, Deepak B, Novak JI, Rolfe B, Kron T. Infill selection for 3D printed radiotherapy immobilisation devices. Biomed Phys Eng Express 2020; 6. [DOI: 10.1088/2057-1976/abb981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/17/2020] [Indexed: 12/19/2022]
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17
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Posar JA, Davis J, Large MJ, Basiricò L, Ciavatti A, Fraboni B, Dhez O, Wilkinson D, Sellin PJ, Griffith MJ, Lerch MLF, Rosenfeld A, Petasecca M. Characterization of an organic semiconductor diode for dosimetry in radiotherapy. Med Phys 2020; 47:3658-3668. [PMID: 32395821 DOI: 10.1002/mp.14229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/15/2020] [Accepted: 05/01/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE The development of novel detectors for dosimetry in advanced radiotherapy modalities requires materials that have a water equivalent response to ionizing radiation such that characterization of radiation beams can be performed without the need for complex calibration procedures and correction factors. Organic semiconductors are potentially an ideal technology in fabricating devices for dosimetry due to tissue equivalence, mechanical flexibility, and relatively cheap manufacturing cost. The response of a commercial organic photodetector (OPD), coupled to a plastic scintillator, to ionizing radiation from a linear accelerator and orthovoltage x-ray tube has been characterized to assess its potential as a dosimeter for radiotherapy. The radiation hardness of the OPD has also been investigated to demonstrate its longevity for such applications. METHODS Radiation hardness measurements were achieved by observing the response of the OPD to the visible spectrum and 70 keV x rays after pre-exposure to 40 kGy of ionizing radiation. The response of a preirradiated OPD to 6-MV photons from a linear accelerator in reference conditions was compared to a nonirradiated OPD with respect to direct and indirect (RP400 plastic scintillator) detection mechanisms. Dose rate dependence of the OPD was measured by varying the surface-to-source distance between 90 and 300 cm. Energy dependence was characterized from 29.5 to 129 keV with an x-ray tube. The percentage depth dose (PDD) curves were measured from 0.5 to 20 cm and compared to an ionization chamber. RESULTS The OPD sensitivity to visible light showed substantial degradation of the broad 450 to 600 nm peak from the donor after irradiation to 40 kGy. After irradiation, the spectral shape has a dominant absorbance peak at 370 nm, as the acceptor better withstood radiation damage. Its response to x rays stabilized to 30% after 35 kGy, with a 0.5% difference between 770 Gy increments. The OPD exhibited reproducible detection of ionizing radiation when coupled with a scintillator. Indirect detection showed a linear response from 25 to 500 cGy and constant response to dose rates from 0.31 Gy/pulse to 3.4 × 10-4 Gy/pulse. However, without the scintillator, response increased by 100% at low dose rates. Energy independence between 100 keV and 1.2 MeV advocates their use as a dosimeter without beam correction factors. A dependence on the scintillator thickness used during a comparison of the PDD to the ionizing chamber was identified. A 1-mm-thick scintillator coupled with the OPD demonstrated the best agreement of ± 3%. CONCLUSIONS The response of OPDs to ionizing radiation has been characterized, showing promising use as a dosimeter when coupled with a plastic scintillator. The mechanisms of charge transport and trapping within organic materials varies for visible and ionizing radiation, due to differing properties for direct and indirect detection mechanisms and observing a substantial decrease in sensitivity to the visible spectrum after 40 kGy. This study proved that OPDs produce a stable response to 6-MV photons, and with a deeper understanding of the charge transport mechanisms due to exposure to ionizing radiation, they are promising candidates as the first flexible, water equivalent, real-time dosimeter.
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Affiliation(s)
- Jessie A Posar
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Jeremy Davis
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Matthew J Large
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Laura Basiricò
- Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, Bologna, 40127, Italy
| | - Andrea Ciavatti
- Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, Bologna, 40127, Italy
| | - Beatrice Fraboni
- Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, Bologna, 40127, Italy
| | - Olivier Dhez
- ISORG, 60 Rue des berges, Parc Polyetc, Immeuble Tramontane, Grenoble, 38000, France
| | - Dean Wilkinson
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Paul J Sellin
- Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Matthew J Griffith
- Priority Research Centre for Organic Electronics, University of Newcastle, Callaghan, NSW, 2308, Australia.,School of Aeronautical, Mechanical and Mechatronic Engineering, University of Sydney, Camperdown, NSW, 2050, Australia
| | - Michael L F Lerch
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Marco Petasecca
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
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Cho JD, Son J, Sung J, Choi CH, Kim JS, Wu HG, Park JM, Kim JI. Flexible film dosimeter for in vivo dosimetry. Med Phys 2020; 47:3204-3213. [PMID: 32248523 DOI: 10.1002/mp.14162] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/20/2020] [Accepted: 03/23/2020] [Indexed: 02/03/2023] Open
Abstract
PURPOSE The aims of this study were to develop a flexible film dosimeter applicable to the irregular surface of a patient for in vivo dosimetry and to evaluate the device's dosimetric characteristics. METHODS A flexible film dosimeter with active layers consisting of radiochromic-sensitive films and flexible silicone materials was constructed. The dose-response, sensitivity, scanning orientation dependence, energy dependence, and dose rate dependence of the flexible film dosimeter were tested. Irradiated dosimeters were scanned 24 h post-irradiation, and the region of interest was 5 mm × 5 mm. Biological stability tests ensured the safety of application of the flexible film dosimeter for patients. A preliminary clinical study with the flexible film dosimeter was implemented on four patients. RESULTS The red channel demonstrated the highest sensitivity among all channels, and the response sensitivity of the dosimeter decreased with the applied dose, which were the same as the characteristics of GAFCHROMIC EBT3 radiochromic films. The flexible film dosimeter showed no significant energy dependence for photon beams of 6 MV, 6 MV flattening filter-free (FFF), 10 MV, and 15 MV. The flexible film dosimeter showed no substantial dose rate dependence with 6 or 6 MV FFF. In terms of biological stability, the flexible film dosimeter demonstrated no cytotoxicity, no irritation, and no skin sensitization. In the preliminary clinical study, the dose differences between the measurements with the flexible film dosimeter and calculations with the treatment planning system ranged from -0.1% to 1.2% for all patients. CONCLUSIONS The dosimeter developed in this study is a flexible film capable of attachment to a curved skin surface. The biological test results indicate the stability of the flexible film dosimeter. The preliminary clinical study showed that the flexible film dosimeter can be successfully applied as an in vivo dosimeter.
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Affiliation(s)
- Jin Dong Cho
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Jaeman Son
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - Jiwon Sung
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - Chang Heon Choi
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Hong-Gyun Wu
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Robotics Research Laboratory for Extreme Environments, Advanced Institute of Convergence Technology, Suwon, 16229, Republic of Korea
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
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19
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Shameem T, Bennie N, Butson M, Thwaites D. A comparison between EPSON V700 and EPSON V800 scanners for film dosimetry. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2020; 43:10.1007/s13246-019-00837-3. [PMID: 31912461 DOI: 10.1007/s13246-019-00837-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022]
Abstract
Radiochromic film is a good dosimeter choice for patient QA for complex treatment techniques (IMRT, VMAT, SABR, SBRT) because of its near tissue equivalency, very high spatial resolution and established method of use. Commercial scanners are usually used for film dosimetry, among which EPSON scanners are the most common. NCCI have used an EPSON V700 scanner, but recently acquired a new model EPSON V800 scanner. The purpose of this work was to evaluate any differences between these two scanners to consider whether they can be used interchangeably or not. Different aspects of film dosimetry, e.g. lateral response artefact (LRA) effect, orientation effect, scanner response etc., were compared. EBT3 films were irradiated with 40 × 40 cm2 field size 6 MV beams and scanned in both the scanners. The scanned images were read in ImageJ V1.49 software. The data obtained was then copied in MS Excel to compare the scanners. The V800 scanner causes more polarisation, which results in more LRA effect than for the V700 scanner. The responses of the scanners in all three colour channels are not the same for the same film and irradiation. The V800 scanner shows an increase of response of up to 1.6% compared to 3.7% increase in the V700 scanner after scanning a piece of irradiated film 20 times. The scanners cannot be used interchangeably. The correction factors for LRA effect and the calibration curves are different. Further characterisation, evaluation and commissioning is required before clinical use.
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Affiliation(s)
- Tarafder Shameem
- North Coast Cancer Institute, Lismore, NSW, Australia.
- School of Physics, Institute of Medical Physics, University of Sydney, Sydney, NSW, Australia.
| | - Nick Bennie
- North Coast Cancer Institute, Lismore, NSW, Australia
| | - Martin Butson
- School of Physics, Institute of Medical Physics, University of Sydney, Sydney, NSW, Australia
- Department of Radiation Oncology, Chris O'Brien Lifehouse, Sydney, NSW, Australia
| | - David Thwaites
- School of Physics, Institute of Medical Physics, University of Sydney, Sydney, NSW, Australia
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Kim JI, Cho JD, Son J, Choi CH, Wu HG, Park JM. Contact lens-type ocular in vivo dosimeter for radiotherapy. Med Phys 2019; 47:722-735. [PMID: 31743441 DOI: 10.1002/mp.13932] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 10/26/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
PURPOSE This study aimed to (a) develop a contact lens-type ocular in vivo dosimeter (CLOD) that can be worn directly on the eye and (b) assess its dosimetric characteristics and biological stability for radiation therapy. METHODS The molder of a soft contact lens was directly used to create the dosimeter, which included a radiation-sensitive component - an active layer similar to a radiochromic film - to measure the delivered dose. A flatbed scanner with a reflection mode was used to measure the change in optical density due to irradiation. The sensitivity, energy, dose rate, and angular dependence were tested, and the uncertainty in determining the dose was calculated using error propagation analysis. Sequential biological stability tests, specifically, cytotoxicity and ocular irritation tests, were conducted to ensure the safe application of the CLOD to patients. RESULTS The dosimeter demonstrated high sensitivity in the low dose region, and the sensitivity linearly decreased with the dose. The responses obtained for the 10 and 15 MV photon beams were 1.7% and 1.9% higher compared to the 6 MV photon beam. A strong dose rate dependence was not obtained for the CLOD. Angular dependence was observed from 90° to 180° with a difference in response from 1% to 2%. The total uncertainty in error propagation analysis decreased as a function of the dose in the red channel. For a dose range of 0 to 50 cGy, the total uncertainties for 5, 10, and 50 cGy were 14.2%, 8.9%, and 5%, respectively. Quantitative evaluation using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method presented no cytotoxicity. Further, no corneal opacity, iris reaction, or conjunctival inflammation was observed. CONCLUSIONS The CLOD is the first dosimeter that can be worn close to the eye. The results of cytotoxicity and irritation tests indicate that it is a stable medical device. The evaluation of dose characteristics in open field conditions shows that the CLOD can be applied to an in vivo dosimeter in radiotherapy.
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Affiliation(s)
- Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - Jin-Dong Cho
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Department of Radiation Oncology, College of Medicine, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jaeman Son
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - Chang Heon Choi
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - Hong-Gyun Wu
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Republic of Korea.,Robotics Research Laboratory for Extreme Environments, Advanced Institute of Convergence Technology, Suwon, 16229, Republic of Korea
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21
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Esplen N, Therriault-Proulx F, Beaulieu L, Bazalova-Carter M. Preclinical dose verification using a 3D printed mouse phantom for radiobiology experiments. Med Phys 2019; 46:5294-5303. [PMID: 31461781 DOI: 10.1002/mp.13790] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/16/2019] [Accepted: 08/16/2019] [Indexed: 01/14/2023] Open
Abstract
PURPOSE Dose verification in preclinical radiotherapy is often challenged by a lack of standardization in the techniques and technologies commonly employed along with the inherent difficulty of dosimetry associated with small-field kilovoltage sources. As a consequence, the accuracy of dosimetry in radiobiological research has been called into question. Fortunately, the development and characterization of realistic small-animal phantoms has emerged as an effective and accessible means of improving dosimetric accuracy and precision in this context. The application of three-dimensional (3D) printing, in particular, has enabled substantial improvements in the conformity of representative phantoms with respect to the small animals they are modeled after. In this study, our goal was to evaluate a fully 3D printed mouse phantom for use in preclinical treatment verification of sophisticated therapies for various anatomical targets of therapeutic interest. METHODS An anatomically realistic mouse phantom was 3D printed based on segmented microCT data of a tumor-bearing mouse. The phantom was modified to accommodate both laser-cut EBT3 radiochromic film within the mouse thorax and a plastic scintillator dosimeter (PSD), which may be placed within the brain, abdomen, or 1-cm flank subcutaneous tumor. Various treatments were delivered on an image-guided small-animal irradiator in order to determine the doses to isocenter using a PSD and validate lateral- and depth-dose distributions using film dosimeters. On-board cone-beam CT imaging was used to localize isocenter to the film plane or PSD active element prior to irradiation. The PSD irradiations comprised a 3 × 3 mm2 brain arc, 5 × 5 mm2 parallel-opposed pair (POP), and 5-beam 10 × 10 mm2 abdominal coplanar arrangement while two-dimensional (2D) film dose distributions were acquired using a 3 × 3 mm2 arc and both 5 × 5 and 10 × 10 mm2 3-beam coplanar plans. A validated Monte Carlo (MC) model of the source was used as to verify the accuracy of the film and PSD dose measurements. computer-aided design (CAD) geometries for the mouse phantom and dosimeters were imported directly into the MC code to allow for highly accurate reproduction of the physical experiment conditions. Experimental and MC-derived film data were co-registered and film dose profiles were compared for points above 90% of the dose maximum. Point dose measurements obtained with the PSD were similarly compared for each of the candidate (brain, abdomen, and tumor) treatment sites. RESULTS For each treatment configuration and anatomical target, the MC-calculated and measured doses met the proposed 5% agreement goal for dose accuracy in radiobiology experiments. The 2D film and MC dose distributions were successfully registered and mean doses for lateral profiles were found to agree to within 2.3% in all cases. Isocentric point-dose measurements taken with the PSD were similarly consistent, with a maximum percentage deviation of 3.2%. CONCLUSIONS Our study confirms the utility of 3D printed phantom design in providing accurate dose estimates for a variety of preclinical treatment paradigms. As a tool for pretreatment dose verification, the phantom may be of particular interest to researchers for its ability to facilitate precise dosimetry while fostering a reduction in cost for radiobiology experiments.
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Affiliation(s)
- Nolan Esplen
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - François Therriault-Proulx
- Departement de Radio-Oncologie and Centre de recherche du CHU de Quebec, CHU de Quebec, Quebec, QC, G1R 3S1, Canada
| | - Luc Beaulieu
- Departement de Radio-Oncologie and Centre de recherche du CHU de Quebec, CHU de Quebec, Quebec, QC, G1R 3S1, Canada.,Departement de physique and Centre de recherche sur le Cancer, Université Laval, Quebec, QC, G1V 0A6, Canada
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Billas I, Bouchard H, Oelfke U, Duane S. The effect of magnetic field strength on the response of Gafchromic EBT-3 film. Phys Med Biol 2019; 64:06NT03. [PMID: 30731443 DOI: 10.1088/1361-6560/ab0503] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
With the advent of MRI-guided radiotherapy, the suitability of commercially available radiation dose detectors needs to be assessed. The aim of this study was to investigate the effect of the magnetic field (B-field) on the response of the Gafchromic EBT-3 films. Moreover, as an independent study, we contribute to clarifying the inconsistency of the results of recent published studies, on the effect of B-field on the sensitivity of Gafchromic films. A 60Co beam was used to irradiate film samples in an electromagnet. An in-house PMMA phantom was designed to fit in the 5 cm gap between the two poles of the magnet. The phantom consists of two symmetrical plates where a film can be inserted. The absorbed dose rate of the 60Co beam for zero B-field was measured using alanine pellets in a Farmer-type holder. A 12-point response curve was created, representing [Formula: see text] as a function of dose, for each of five different B-field strengths (0 T to 2 T). This study finds that there is at most a small effect of the magnetic field on the response of EBT-3 film. In terms of netOD (red channel) the change in response varied from ‒0.0011 at 0.5 T to 0.0045 at 2.0 T, with a standard uncertainty of 0.0030. If uncorrected, this would lead to an error in film-measured dose, for the red channel, of 2.4% at 2 T, with a standard uncertainty on dose of 1.4%. Results are also presented for B-field strengths of 0.5 T, 1 T and 1.5 T, which are all zero within the measurement uncertainty. Comparison between other studies is also presented. Considering the small change on dose determined with EBT-3 when irradiated under the presence of B-field and taking into account the overall uncertainty in dosimetry using EBT-3 film achieved in this work, EBT-3 is assessed to be a suitable detector for relative and absolute dosimetry, with appropriate corrections, in MRI-guided radiotherapy. The results of the current work also elucidate the inconsistency on the reports from previous studies and demonstrate the necessity of similar investigations by independent teams, especially if the existing results may be in conflict.
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Affiliation(s)
- Ilias Billas
- National Physical Laboratory, Chemical, Medical and Environmental Science Department, Teddington, United Kingdom. Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom. Author to whom correspondence should be addressed
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Tagiling N, Ab Rashid R, Azhan SNA, Dollah N, Geso M, Rahman WN. Effect of scanning parameters on dose-response of radiochromic films irradiated with photon and electron beams. Heliyon 2018; 4:e00864. [PMID: 30364574 PMCID: PMC6197593 DOI: 10.1016/j.heliyon.2018.e00864] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/11/2018] [Accepted: 10/11/2018] [Indexed: 12/04/2022] Open
Abstract
Proper dosimetry settings are crucial in radiotherapy to ensure accurate radiation dose delivery. This work evaluated scanning parameters as affecting factors in reading the dose-response of EBT2 and EBT3 radiochromic films (RCFs) irradiated with clinical photon and electron beams. The RCFs were digitised using Epson® Expression® 10000XL flatbed scanner and image analyses of net optical density (netOD) were conducted using five scanning parameters i.e. film type, resolution, image bit depth, colour to grayscale transformation and image inversion. The results showed that increasing spatial resolution and deepening colour depth did not improve film sensitivity, while grayscale scanning caused sensitivity reduction below than that detected in the Red-channel. It is also evident that invert and colour negative film type selection negated netOD values, hence unsuitable for scanning RCFs. In conclusion, choosing appropriate scanning parameters are important to maintain preciseness and reproducibility in films dosimetry.
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Affiliation(s)
- Nashrulhaq Tagiling
- Medical Radiation Programme, School of Health Sciences, Universiti Sains Malaysia (Health Campus), Kelantan, Malaysia
| | - Raizulnasuha Ab Rashid
- Medical Radiation Programme, School of Health Sciences, Universiti Sains Malaysia (Health Campus), Kelantan, Malaysia
| | - Siti Nur Amirah Azhan
- Medical Radiation Programme, School of Health Sciences, Universiti Sains Malaysia (Health Campus), Kelantan, Malaysia
| | - Norhayati Dollah
- Department of Nuclear Medicine, Radiotherapy and Oncology, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
| | - Moshi Geso
- Division of Medical Radiation, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Wan Nordiana Rahman
- Medical Radiation Programme, School of Health Sciences, Universiti Sains Malaysia (Health Campus), Kelantan, Malaysia
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Tomori S, Kadoya N, Takayama Y, Kajikawa T, Shima K, Narazaki K, Jingu K. A deep learning-based prediction model for gamma evaluation in patient-specific quality assurance. Med Phys 2018; 45:4055-4065. [PMID: 30066388 DOI: 10.1002/mp.13112] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Patient-specific quality assurance (QA) measurement is conducted to confirm the accuracy of dose delivery. However, measurement is time-consuming and places a heavy workload on the medical physicists and radiological technologists. In this study, we proposed a prediction model for gamma evaluation, based on deep learning. We applied the model to a QA measurement dataset of prostate cancer cases to evaluate its practicality. METHODS Sixty pretreatment verification plans from prostate cancer patients treated using intensity modulated radiation therapy were collected. Fifteen-layer convolutional neural networks (CNN) were developed to learn the sagittal planar dose distributions from a RT-3000 QA phantom (R-TECH.INC., Tokyo, Japan). The percentage gamma passing rate (GPR) was measured using GAFCHROMIC EBT3 film (Ashland Specialty Ingredients, Covington, USA). The input training data also included the volume of the PTV (planning target volume), rectum, and overlapping region, measured in cm3 , and the monitor unit values for each field. The network produced predicted GPR values at four criteria: 2%(global)/2 mm, 3%(global)/2 mm, 2%(global)/3 mm, and 3%(global)/3 mm. Adam, an algorithm for first-order gradient-based optimization of stochastic objective functions, was used for learning and for optimizing the CNN-based model. Fivefold cross-validation was applied to validate the performance of the proposed method. Forty cases were used for training and validation set in fivefold cross-validation, and the remaining 20 cases were used for the test set. The predicted and measured GPR values were compared. RESULTS A linear relationship was found between the measured and predicted values, for each of the four criteria. Spearman rank correlation coefficients in validation set between measured and predicted GPR values at four criteria were 0.73 at 2%/2 mm, 0.72 at 3%/2 mm, 0.74 at 2%/3 mm, and 0.65 at 3%/3 mm, respectively (P < 0.01). The Spearman rank correlation coefficients in the test set were 0.62 (P < 0.01) at 2%/2 mm, 0.56 (P < 0.01) at 3%/2 mm, 0.51 (P = 0.02) at 2%/3 mm, and 0.32 (P = 0.16) at 3%/3 mm. These results demonstrated a strong or moderate correlation between the predicted and measured values. CONCLUSIONS We developed a CNN-based prediction model for patient-specific QA of dose distribution in prostate treatment. Our results suggest that deep learning may provide a useful prediction model for gamma evaluation of patient-specific QA in prostate treatment planning.
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Affiliation(s)
- Seiji Tomori
- Department of Radiology, National Hospital Organization Sendai Medical Center, Sendai, Miyagi, 983-8520, Japan
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Noriyuki Kadoya
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Yoshiki Takayama
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Tomohiro Kajikawa
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Katsumi Shima
- Department of Radiology, National Hospital Organization Hakodate National Hospital, Hakodate, Hokkaido, 041-8512, Japan
| | - Kakutarou Narazaki
- Department of Radiology, National Hospital Organization Sendai Medical Center, Sendai, Miyagi, 983-8520, Japan
| | - Keiichi Jingu
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
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Mourya A, Aggarwal LM, Mandal A, Shahi UP, Ram C, Asthana AK, Pradhan S. An inexpensive method of small photon field dosimetry with EBT3 radiochromic film. HEALTH AND TECHNOLOGY 2018. [DOI: 10.1007/s12553-018-0233-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Vera-Sánchez JA, Ruiz-Morales C, González-López A. Monte Carlo uncertainty analysis of dose estimates in radiochromic film dosimetry with single-channel and multichannel algorithms. Phys Med 2018; 47:23-33. [PMID: 29609815 DOI: 10.1016/j.ejmp.2018.02.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 10/18/2022] Open
Abstract
PURPOSE To provide a multi-stage model to calculate uncertainty in radiochromic film dosimetry with Monte-Carlo techniques. This new approach is applied to single-channel and multichannel algorithms. MATERIAL AND METHODS Two lots of Gafchromic EBT3 are exposed in two different Varian linacs. They are read with an EPSON V800 flatbed scanner. The Monte-Carlo techniques in uncertainty analysis provide a numerical representation of the probability density functions of the output magnitudes. From this numerical representation, traditional parameters of uncertainty analysis as the standard deviations and bias are calculated. Moreover, these numerical representations are used to investigate the shape of the probability density functions of the output magnitudes. Also, another calibration film is read in four EPSON scanners (two V800 and two 10000XL) and the uncertainty analysis is carried out with the four images. RESULTS The dose estimates of single-channel and multichannel algorithms show a Gaussian behavior and low bias. The multichannel algorithms lead to less uncertainty in the final dose estimates when the EPSON V800 is employed as reading device. In the case of the EPSON 10000XL, the single-channel algorithms provide less uncertainty in the dose estimates for doses higher than four Gy. CONCLUSION A multi-stage model has been presented. With the aid of this model and the use of the Monte-Carlo techniques, the uncertainty of dose estimates for single-channel and multichannel algorithms are estimated. The application of the model together with Monte-Carlo techniques leads to a complete characterization of the uncertainties in radiochromic film dosimetry.
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Affiliation(s)
- Juan Antonio Vera-Sánchez
- Hospital Universitari Sant Joan de Reus, Servicio de Física Médica, Reus (Tarragona), Spain; PhD Programme in Physics and Space Science of the University of Granada, Granada, Spain.
| | - Carmen Ruiz-Morales
- PhD Programme in Physics and Space Science of the University of Granada, Granada, Spain
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Accuracy and efficiency of published film dosimetry techniques using a flat-bed scanner and EBT3 film. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2018; 41:117-128. [DOI: 10.1007/s13246-018-0620-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 01/14/2018] [Indexed: 11/26/2022]
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Hammer CG, Rosen BS, Fagerstrom JM, Culberson WS, DeWerd LA. Experimental investigation of GafChromic®
EBT3 intrinsic energy dependence with kilovoltage x rays, 137
Cs, and 60
Co. Med Phys 2017; 45:448-459. [DOI: 10.1002/mp.12682] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/13/2017] [Accepted: 11/07/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Cliff G. Hammer
- Department of Medical Physics; School of Medicine and Public Health; University of Wisconsin-Madison; Madison WI 53705 USA
| | - Benjamin Saul Rosen
- Department of Radiation Oncology; University of Michigan; Ann Arbor MI 48109 USA
| | | | - Wesley S. Culberson
- Department of Medical Physics; School of Medicine and Public Health; University of Wisconsin-Madison; Madison WI 53705 USA
| | - Larry A. DeWerd
- Department of Medical Physics; School of Medicine and Public Health; University of Wisconsin-Madison; Madison WI 53705 USA
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Grevillot L, Stock M, Palmans H, Osorio Moreno J, Letellier V, Dreindl R, Elia A, Fuchs H, Carlino A, Vatnitsky S. Implementation of dosimetry equipment and phantoms at the MedAustron light ion beam therapy facility. Med Phys 2017; 45:352-369. [DOI: 10.1002/mp.12653] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/16/2017] [Accepted: 10/19/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Loïc Grevillot
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
| | - Markus Stock
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
| | - Hugo Palmans
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
- National Physical Laboratory; Hampton Road TW11 0LW Teddington UK
| | | | - Virgile Letellier
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
| | - Ralf Dreindl
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
| | - Alessio Elia
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
- Centre Léon Bérard; CREATIS, Université de Lyon, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1; 69007 Lyon France
| | - Hermann Fuchs
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology; Medical University of Vienna; Vienna Austria
- Department of Radiation Oncology; Medical University of Vienna/AKH Vienna; Vienna Austria
| | - Antonio Carlino
- EBG MedAustron GmbH; Marie Curie-Straße 5 A-2700 Wiener Neustadt Austria
- Department of Physics and Chemistry; University of Palermo; Viale delle Scienze, Edificio 18 90128 Palermo Italy
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Bazyar S, Inscoe CR, O’Brian ET, Zhou O, Lee YZ. Minibeam radiotherapy with small animal irradiators; in vitro and in vivo feasibility studies. ACTA ACUST UNITED AC 2017; 62:8924-8942. [DOI: 10.1088/1361-6560/aa926b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Qin Y, Gardner SJ, Kim J, Huang Y, Wen N, Doemer A, Chetty IJ. Technical Note: Evaluation of plastic scintillator detector for small field stereotactic patient-specific quality assurance. Med Phys 2017; 44:5509-5516. [PMID: 28714067 DOI: 10.1002/mp.12471] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate the performance of a commercial plastic scintillator detector (PSD) for small-field stereotactic patient-specific quality assurance (QA) measurements using flattening-filter-free beam. METHODS A total of 10 spherical targets [volume range: (0.03 cc-2 cc)] were planned with two techniques: (a) dynamic conformal arc (DCA-10 plans) and (b) volumetric modulated arc therapy (VMAT-10 plans). All plans were generated using Varian Eclipse treatment planning system, and AcurosXB v.13 algorithm in 1.0 mm grid size. Additionally, 14 previously treated cranial and spine SRS plans were evaluated [6 DCA, 8 VMAT, volume range: (0.04 cc-119.02 cc)]. Plan modulation was quantified via two metrics: MU per prescription dose (MU/Rx) and Average Leaf Pair Opening (ALPO). QA was performed on the Varian Edge linear accelerator equipped with HDMLC. Three detectors were used: (a) PinPoint ion chamber (PTW; active volume 0.015 cc), (b) Exradin W1 PSD (Standard Imaging; active volume 0.002 cc), and (c) Gafchromic EBT3 film (Ashland). PinPoint chamber and PSD were positioned perpendicular to beam axis in a Lucy phantom (Standard Imaging); films were placed horizontally capturing the coronal plane. RESULTS PSD, film, and PinPoint chamber measured average differences of 1.00 ± 1.54%, 1.30 ± 1.69%, and -0.66 ± 2.36%, respectively, compared to AcurosXB dose calculation. As the target volume decreased, PinPoint chamber measured lower doses (maximum -5.07% at 0.07 cc target), while PSD and film measured higher doses (2.87% and 2.54% at 0.03 cc target) than AcurosXB. Film agreed with the benchmark detector PSD by an average difference of 0.31 ± 1.20%, but suffered from larger uncertainty; PinPoint chamber underestimated dose by more than 4% for targets smaller than 0.2 cc. Taking PSD as the measurement standard, DCA plans achieved good QA results across all volumes studied, with an average of -0.07 ± 0.89%; for VMAT plans, PSD measured consistently higher dose (1.95 ± 1.36%) than AcurosXB. Correlation study revealed that plan modulation quantified by both MU/Rx and ALPO correlated significantly with QA results. CONCLUSION Among all three detectors, PSD demonstrated superior performances in plans with small fields and heavy modulation. High consistency and low uncertainty made PSD a suitable detector for clinical routine SRS QA. PinPoint chamber should be avoided for targets smaller than 0.2 cc; film dosimetry can be utilized with careful evaluation of its uncertainty bracket. Compared to PSD measurements, AcurosXB calculation demonstrated high accuracy for nonmodulated small fields. The positive correlation between plan modulation and QA discrepancy calls for our attention for clinical SRS plans with high modulation.
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Affiliation(s)
- Yujiao Qin
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
| | - Stephen J Gardner
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
| | - Joshua Kim
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
| | - Yimei Huang
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
| | - Ning Wen
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
| | - Anthony Doemer
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
| | - Indrin J Chetty
- Radiation Oncology, Henry Ford Health System, 2799 W. Grand Blvd, Detroit, MI, 48202, USA
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Callens MB, Crijns W, Depuydt T, Haustermans K, Maes F, D’Agostino E, Wevers M, Pfeiffer H, Van Den Abeele K. Modeling the dose dependence of the vis-absorption spectrum of EBT3 GafChromic™ films. Med Phys 2017; 44:2532-2543. [DOI: 10.1002/mp.12246] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 02/16/2017] [Accepted: 03/14/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Maarten B. Callens
- Wave Propagation and Signal Processing; KU Leuven - KULAK; Kortrijk 8500 Belgium
| | - Wouter Crijns
- Department of Radiation Oncology; University Hospitals Leuven; Leuven 3000 Belgium
| | - Tom Depuydt
- Department of Radiation Oncology; University Hospitals Leuven; Leuven 3000 Belgium
| | - Karin Haustermans
- Department of Radiation Oncology; University Hospitals Leuven; Leuven 3000 Belgium
| | - Frederik Maes
- Department of Electrical Engineering; ESAT/PSI, KU Leuven; Leuven 3001 Belgium
| | | | - Martine Wevers
- Department of Materials Engineering; KU Leuven; Leuven 3001 Belgium
| | - Helge Pfeiffer
- Department of Materials Engineering; KU Leuven; Leuven 3001 Belgium
| | - Koen Van Den Abeele
- Wave Propagation and Signal Processing; KU Leuven - KULAK; Kortrijk 8500 Belgium
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Akhilesh P, Kulkarni AR, Jamhale SH, Sharma SD, Kumar R, Datta D. Estimation of Eye Lens Dose During Brain Scans Using Gafchromic Xr-QA2 Film in Various Multidetector CT Scanners. RADIATION PROTECTION DOSIMETRY 2017; 174:236-241. [PMID: 27247444 DOI: 10.1093/rpd/ncw132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/06/2016] [Indexed: 06/05/2023]
Abstract
The purpose of this study was to estimate eye lens dose during brain scans in 16-, 64-, 128- and 256-slice multidetector computed tomography (CT) scanners in helical acquisition mode and to test the feasibility of using radiochromic film as eye lens dosemeter during CT scanning. Eye lens dose measurements were performed using Gafchromic XR-QA2 film on a polystyrene head phantom designed with outer dimensions equivalent to the head size of a reference Indian man. The response accuracy of XR-QA2 film was validated by using thermoluminescence dosemeters. The eye lens dose measured using XR-QA2 film on head phantom for plain brain scanning in helical mode ranged from 43.8 to 45.8 mGy. The XR-QA2 film measured dose values were in agreement with TLD measured dose values within a maximum variation of 8.9%. The good correlation between the two data sets confirms the viability of using XR-QA2 film for eye lens dosimetry.
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Affiliation(s)
- Philomina Akhilesh
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT&CRS Building, Anushaktinagar, Mumbai 400094, India
| | - Arti R Kulkarni
- Radiological Safety Division, Atomic Energy Regulatory Board, Niyamak Bhavan, Anushaktinagar, Mumbai 400094, India
| | - Shramika H Jamhale
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT&CRS Building, Anushaktinagar, Mumbai 400094, India
| | - S D Sharma
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT&CRS Building, Anushaktinagar, Mumbai 400094, India
| | - Rajesh Kumar
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT&CRS Building, Anushaktinagar, Mumbai 400094, India
| | - D Datta
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT&CRS Building, Anushaktinagar, Mumbai 400094, India
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Jaccard M, Petersson K, Buchillier T, Germond JF, Durán MT, Vozenin MC, Bourhis J, Bochud FO, Bailat C. High dose-per-pulse electron beam dosimetry: Usability and dose-rate independence of EBT3 Gafchromic films. Med Phys 2017; 44:725-735. [PMID: 28019660 DOI: 10.1002/mp.12066] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 12/02/2016] [Accepted: 12/07/2016] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The aim of this study was to assess the suitability of Gafchromic EBT3 films for reference dose measurements in the beam of a prototype high dose-per-pulse linear accelerator (linac), capable of delivering electron beams with a mean dose-rate (Ḋm ) ranging from 0.07 to 3000 Gy/s and a dose-rate in pulse (Ḋp ) of up to 8 × 106 Gy/s. To do this, we evaluated the overall uncertainties in EBT3 film dosimetry as well as the energy and dose-rate dependence of their response. MATERIAL AND METHODS Our dosimetric system was composed of EBT3 Gafchromic films in combination with a flatbed scanner and was calibrated against an ionization chamber traceable to primary standard. All sources of uncertainties in EBT3 dosimetry were carefully analyzed using irradiations at a clinical radiotherapy linac. Energy dependence was investigated with the same machine by acquiring and comparing calibration curves for three different beam energies (4, 8 and 12 MeV), for doses between 0.25 and 30 Gy. Ḋm dependence was studied at the clinical linac by changing the pulse repetition frequency (f) of the beam in order to vary Ḋm between 0.55 and 4.40 Gy/min, while Ḋp dependence was probed at the prototype machine for Ḋp ranging from 7 × 103 to 8 × 106 Gy/s. Ḋp dependence was first determined by studying the correlation between the dose measured by films and the charge of electrons measured at the exit of the machine by an induction torus. Furthermore, we compared doses from the films to independently calibrated thermo-luminescent dosimeters (TLD) that have been reported as being dose-rate independent up to such high dose-rates. RESULTS We report that uncertainty below 4% (k = 2) can be achieved in the dose range between 3 and 17 Gy. Results also demonstrated that EBT3 films did not display any detectable energy dependence for electron beam energies between 4 and 12 MeV. No Ḋm dependence was found either. In addition, we obtained excellent consistency between films and TLDs over the entire Ḋp range attainable at the prototype linac confirming the absence of any dose-rate dependence within the investigated range (7 × 103 to 8 × 106 Gy/s). This aspect was further corroborated by the linear relationship between the dose-per-pulse (Dp ) measured by films and the charge per pulse (Cp ) measured at the prototype linac exit. CONCLUSION Our study shows that the use of EBT3 Gafchromic films can be extended to reference dosimetry in pulsed electron beams with a very high dose rate. The measurement results are associated with an overall uncertainty below 4% (k = 2) and are dose-rate and energy independent.
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Affiliation(s)
- Maud Jaccard
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Kristoffer Petersson
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Thierry Buchillier
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Maria Teresa Durán
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Marie-Catherine Vozenin
- Department of Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland.,Radio-Oncology Laboratory, DO/CHUV, Lausanne University Hospital Lausanne, Lausanne, Switzerland
| | - Jean Bourhis
- Department of Radiation Oncology, Lausanne University Hospital, Lausanne, Switzerland.,Radio-Oncology Laboratory, DO/CHUV, Lausanne University Hospital Lausanne, Lausanne, Switzerland
| | - François O Bochud
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics (IRA), Lausanne University Hospital, Lausanne, Switzerland
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Cusumano D, Fumagalli ML, Ghielmetti F, Rossi L, Grossi G, Lanzarotti R, Fariselli L, De Martin E. Sum signal dosimetry: A new approach for high dose quality assurance with Gafchromic EBT3. J Appl Clin Med Phys 2017; 18:181-190. [PMID: 28300373 PMCID: PMC5689947 DOI: 10.1002/acm2.12045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 11/17/2016] [Accepted: 11/24/2016] [Indexed: 11/23/2022] Open
Abstract
Gafchromic EBT3 film dosimetry in radiosurgery (RS) and hypofractionated radiotherapy (HRT) is complicated by the limited film accuracy at high fractional doses. The aim of this study is to develop and evaluate sum signal (SS) film dosimetry to increase dose resolution at high fractional doses, thus allowing for use of EBT3 for dose distribution verification of RS/HRT treatments. To characterize EBT3 dose–response, a calibration was performed in the dose range 0.44–26.43 Gy. Red (RC) and green (GC) channel net optical densities were linearly added to produce the SS. Dose resolution and overall accuracy of the dosimetric protocol were estimated and compared for SS,RC, and GC. A homemade Matlab software was developed to compare, in terms of gamma analysis, dose distributions delivered by a Cyberknife on EBT3 films to dose distributions calculated by the treatment planning system. The new SS and conventional single channel (SC) methods were compared, using 3%/1 and 4%/1 mm acceptance criteria, for 20 patient plans. Our analysis shows that the SS dose–response curve is characterized by a steeper trend in comparison with SC, with SS providing a higher dose resolution in the whole dose range investigated. Gamma analysis confirms that the percentage of points satisfying the agreement criteria is significantly higher for SS compared to SC: 95.03% vs. 88.41% (P = 0.014) for 3%/1 mm acceptance criteria and 97.24% vs. 93.58% (P = 0.048) for 4%/1 mm acceptance criteria. This study demonstrates that the SS approach is a new and effective method to improve dosimetric accuracy in the framework of the RS‐HRT patient‐specific quality assurance protocol.
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Affiliation(s)
- Davide Cusumano
- School of Medical Physics, University of Milan, 20133, Milan, Italy
| | - Maria Luisa Fumagalli
- Health Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133, Milan, Italy
| | - Francesco Ghielmetti
- Health Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133, Milan, Italy
| | - Linda Rossi
- School of Medical Physics, University of Milan, 20133, Milan, Italy
| | - Giuliano Grossi
- Department of Computer Science, University of Milan, 20135, Milan, Italy
| | | | - Laura Fariselli
- Department of Neurosurgery, Radiotherapy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133, Milan, Italy
| | - Elena De Martin
- Health Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133, Milan, Italy
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Welch D, Turner L, Speiser M, Randers-Pehrson G, Brenner DJ. Scattered Dose Calculations and Measurements in a Life-Like Mouse Phantom. Radiat Res 2017; 187:433-442. [PMID: 28140787 DOI: 10.1667/rr004cc.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Anatomically accurate phantoms are useful tools for radiation dosimetry studies. In this work, we demonstrate the construction of a new generation of life-like mouse phantoms in which the methods have been generalized to be applicable to the fabrication of any small animal. The mouse phantoms, with built-in density inhomogeneity, exhibit different scattering behavior dependent on where the radiation is delivered. Computer models of the mouse phantoms and a small animal irradiation platform were devised in Monte Carlo N-Particle code (MCNP). A baseline test replicating the irradiation system in a computational model shows minimal differences from experimental results from 50 Gy down to 0.1 Gy. We observe excellent agreement between scattered dose measurements and simulation results from X-ray irradiations focused at either the lung or the abdomen within our phantoms. This study demonstrates the utility of our mouse phantoms as measurement tools with the goal of using our phantoms to verify complex computational models.
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Affiliation(s)
- David Welch
- a Center for Radiological Research, Columbia University, New York, New York
| | - Leah Turner
- a Center for Radiological Research, Columbia University, New York, New York
| | - Michael Speiser
- b Englewood Hospital and Medical Center, Englewood, New Jersey
| | | | - David J Brenner
- a Center for Radiological Research, Columbia University, New York, New York
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Castriconi R, Ciocca M, Mirandola A, Sini C, Broggi S, Schwarz M, Fracchiolla F, Martišíková M, Aricò G, Mettivier G, Russo P. Dose–response of EBT3 radiochromic films to proton and carbon ion clinical beams. Phys Med Biol 2016; 62:377-393. [DOI: 10.1088/1361-6560/aa5078] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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39
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Reynoso FJ, Curcuru A, Green O, Mutic S, Das IJ, Santanam L. Technical Note: Magnetic field effects on Gafchromic-film response in MR-IGRT. Med Phys 2016; 43:6552. [DOI: 10.1118/1.4967486] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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40
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Characterization of stochastic noise and post-irradiation density growth for reflective-type radiochromic film in therapeutic photon beam dosimetry. Phys Med 2016; 32:1314-1320. [PMID: 27473441 DOI: 10.1016/j.ejmp.2016.07.091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 07/15/2016] [Accepted: 07/17/2016] [Indexed: 11/23/2022] Open
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41
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Marroquin EYL, Herrera González JA, Camacho López MA, Barajas JEV, García-Garduño OA. Evaluation of the uncertainty in an EBT3 film dosimetry system utilizing net optical density. J Appl Clin Med Phys 2016; 17:466-481. [PMID: 27685125 PMCID: PMC5874103 DOI: 10.1120/jacmp.v17i5.6262] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 05/19/2016] [Accepted: 05/16/2016] [Indexed: 11/23/2022] Open
Abstract
Radiochromic film has become an important tool to verify dose distributions for intensity-modulated radiotherapy (IMRT) and quality assurance (QA) procedures. A new radiochromic film model, EBT3, has recently become available, whose composition and thickness of the sensitive layer are the same as those of previous EBT2 films. However, a matte polyester layer was added to EBT3 to prevent the formation of Newton's rings. Furthermore, the symmetrical design of EBT3 allows the user to eliminate side-orientation dependence. This film and the flatbed scanner, Epson Perfection V750, form a dosimetry system whose intrinsic characteristics were studied in this work. In addition, uncertainties associated with these intrinsic characteristics and the total uncertainty of the dosimetry system were determined. The analysis of the response of the radiochromic film (net optical density) and the fitting of the experimental data to a potential function yielded an uncertainty of 2.6%, 4.3%, and 4.1% for the red, green, and blue channels, respectively. In this work, the dosimetry system presents an uncertainty in resolving the dose of 1.8% for doses greater than 0.8 Gy and less than 6 Gy for red channel. The films irradiated between 0 and 120 Gy show differences in the response when scanned in portrait or landscape mode; less uncertainty was found when using the portrait mode. The response of the film depended on the position on the bed of the scanner, contributing an uncertainty of 2% for the red, 3% for the green, and 4.5% for the blue when placing the film around the center of the bed of scanner. Furthermore, the uniformity and reproducibility radiochromic film and reproducibility of the response of the scanner contribute less than 1% to the overall uncertainty in dose. Finally, the total dose uncertainty was 3.2%, 4.9%, and 5.2% for red, green, and blue channels, respectively. The above uncertainty values were obtained by mini-mizing the contribution to the total dose uncertainty of the film orientation and film homogeneity.
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42
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Grid patterns, spatial inter-scan variations and scanning reading repeatability in radiochromic film dosimetry. Phys Med 2016; 32:1072-81. [DOI: 10.1016/j.ejmp.2016.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/21/2016] [Accepted: 08/03/2016] [Indexed: 11/23/2022] Open
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43
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Vera Sánchez JA, Ruiz Morales C, González López A. Characterization of noise and digitizer response variability in radiochromic film dosimetry. Impact on treatment verification. Phys Med 2016; 32:1167-74. [PMID: 27595366 DOI: 10.1016/j.ejmp.2016.08.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 08/21/2016] [Accepted: 08/23/2016] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To study how noise and scanner response variability affect radiochromic film dosimetry. METHODS Five treatment plans were analyzed in this work with two different multichannel protocols: the multichannel algorithm of Mayer et al. and the efficient protocol of Lewis et al. RESULTS AND CONCLUSION The multichannel protocol of Mayer et al. is not able to compensate variability in scanner response, which is an important issue for radiochromic film dosimetry. The efficient protocol compensates variations of scanner response, so dose values and gamma scores become more accurate and reproducible. The compensation of digitizer scan variability of the efficient protocol, together with time averaging improve radiochromic film dosimetry. Noise is related to selected resolution in the scanner, our results show that if high resolution measurements are required, de-noising should be considered.
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44
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Reynoso FJ, Tailor R, Wang CKC, Cho SH. Comparison of filtered x-ray spectra and depth doses derived from a hybrid Monte Carlo model of an orthovoltage x-ray unit with experimental measurements. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/4/045011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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45
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Tamponi M, Bona R, Poggiu A, Marini P. A new form of the calibration curve in radiochromic dosimetry. Properties and results. Med Phys 2016; 43:4435. [DOI: 10.1118/1.4954208] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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46
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In vivo dosimetry using radiochromic films (EBT-2) during intraoperative radiotherapy. JOURNAL OF RADIOTHERAPY IN PRACTICE 2016. [DOI: 10.1017/s1460396916000273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
AbstractBackgroundIntraoperative radiotherapy is a method of choice to deliver a critical radiation dose to the tumour bed immediately after surgical excision.AimThe purpose of this work is to check the dose delivered to the patients during intraoperative electron beam radiation therapy (IOERT) in the conservative treatment of breast cancer, by means of reference dose measurement using radiochromic (EBT-2) films.Material and methodsNinety patients with early-stage breast cancer underwent exclusive IOERT to the tumour bed using a LIAC linear accelerator. Absolute dose measurements were done with film pieces. After irradiation, the pixel values of the films were obtained via MATLAB and ImageJ softwares. Calibration curve was also used for calculating net optical density. Expected dose was compared to the patient delivered dose.ResultsThe mean deviation of the delivered dose from the expected one was 2·56% that is well in the accepted criteria. Only in one case, there was a larger deviation due to barometer miscalibration.FindingsEBT-2 film response is independent from dose-per-pulse and as it was shown in this study it can be robustly used during breast IOERT for dosimetric and also positioning verifications.
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47
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Kurosu K, Sumida I, Mizuno H, Otani Y, Oda M, Isohashi F, Seo Y, Suzuki O, Ogawa K. Curtailing patient-specific IMRT QA procedures from 2D dose error distribution. JOURNAL OF RADIATION RESEARCH 2016; 57:258-264. [PMID: 26661854 PMCID: PMC4915532 DOI: 10.1093/jrr/rrv084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/30/2015] [Accepted: 10/22/2015] [Indexed: 06/05/2023]
Abstract
A patient-specific quality assurance (QA) test is conducted to verify the accuracy of dose delivery. It generally consists of three verification processes: the absolute point dose difference, the planar dose differences at each gantry angle, and the planar dose differences by 3D composite irradiation. However, this imposes a substantial workload on medical physicists. The objective of this study was to determine whether our novel method that predicts the 3D delivered dose allows certain patient-specific IMRT QAs to be curtailed. The object was IMRT QA for the pelvic region with regard to point dose and composite planar dose differences. We compared measured doses, doses calculated in the treatment planning system, and doses predicted by in-house software. The 3D predicted dose was reconstructed from the per-field measurement by incorporating the relative dose error distribution into the original dose grid of each beam. All point dose differences between the measured and the calculated dose were within ±3%, whereas 93.3% of them between the predicted and the calculated dose were within ±3%. As for planar dose differences, the gamma passing rates between the calculated and the predicted dose were higher than those between the calculated and the measured dose. Comparison and statistical analysis revealed a correlation between the predicted and the measured dose with regard to both point dose and planar dose differences. We concluded that the prediction-based approach is an accurate substitute for the conventional measurement-based approach in IMRT QA for the pelvic region. Our novel approach will help medical physicists save time on IMRT QA.
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Affiliation(s)
- Keita Kurosu
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan Department of Radiology, Osaka University Hospital, Osaka, 565-0871, Japan
| | - Iori Sumida
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Hirokazu Mizuno
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Yuki Otani
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Michio Oda
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan Department of Radiology, Osaka University Hospital, Osaka, 565-0871, Japan
| | - Fumiaki Isohashi
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Yuji Seo
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Osamu Suzuki
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
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48
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Devic S, Tomic N, Lewis D. Reference radiochromic film dosimetry: Review of technical aspects. Phys Med 2016; 32:541-56. [DOI: 10.1016/j.ejmp.2016.02.008] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 01/30/2016] [Accepted: 02/23/2016] [Indexed: 11/29/2022] Open
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49
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Determination of the ion recombination correction factor for intraoperative electron beams. Z Med Phys 2016; 26:35-44. [DOI: 10.1016/j.zemedi.2015.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 05/29/2015] [Accepted: 06/15/2015] [Indexed: 11/15/2022]
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50
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García-Garduño OA, Lárraga-Gutiérrez JM, Rodríguez-Villafuerte M, Martínez-Dávalos A, Rivera-Montalvo T. Effect of correction methods of radiochromic EBT2 films on the accuracy of IMRT QA. Appl Radiat Isot 2016; 107:121-126. [PMID: 26492322 DOI: 10.1016/j.apradiso.2015.09.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 09/24/2015] [Accepted: 09/30/2015] [Indexed: 12/01/2022]
Affiliation(s)
- O A García-Garduño
- Laboratorio de Física Médica & Unidad de Radioneurocirugía, Instituto Nacional de Neurología y Neurocirugía, Tlalpan, 14269 Mexico D.F., Mexico; Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Legaria, Instituto Politécnico Nacional, Lindavista, 11500 Mexico D.F., Mexico.
| | - J M Lárraga-Gutiérrez
- Laboratorio de Física Médica & Unidad de Radioneurocirugía, Instituto Nacional de Neurología y Neurocirugía, Tlalpan, 14269 Mexico D.F., Mexico
| | - M Rodríguez-Villafuerte
- Instituto de Física, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510, Mexico
| | - A Martínez-Dávalos
- Instituto de Física, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510, Mexico
| | - T Rivera-Montalvo
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Legaria, Instituto Politécnico Nacional, Lindavista, 11500 Mexico D.F., Mexico
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