1
|
Kirk JS, Rowbottom CG. Evaluation of radiotherapy planning approaches for head and neck patients with tumors close to the skin surface. J Appl Clin Med Phys 2024:e14473. [PMID: 39031437 DOI: 10.1002/acm2.14473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/22/2024] [Accepted: 06/28/2024] [Indexed: 07/22/2024] Open
Abstract
PURPOSE In radiotherapy of the head and neck (H&N) it is common for the clinical target volume (CTV) to extend to the patient's skin. Adding a margin for set-up uncertainty and delivery creates a planning target volume (PTV) that extends beyond the patient surface. This can result in excessive fluence being delivered to the build-up region and therefore the skin. This study evaluates four different planning methods used when inverse-planning H&N radiotherapy treatments with CTV extending to the skin. The aim of the study was to determine which planning method gives superior plan quality. METHOD Ten H&N cancer patients with a CTV contoured to the skin were inverse-planned using four planning methods. The planning methods compared were: cropping the optimization PTV back from the skin surface by 5.0, 3.0, and 0.0 mm and a virtual bolus method. For each planning method, the increased fluence at the skin surface was analyzed. The CTV coverage and skin doses were compared. Plan robustness was evaluated by applying an isocenter shift of ±3.0 mm in the major axes. RESULTS The planning method cropping the PTV 0.0 mm from the skin surface results in an increased fluence in the build-up region. The average volume of CTV receiving 98% of the prescription dose was 89.6% ± 3.4%, 91.6% ± 2.4%, and 93.5% ± 1.7% when cropped 5.0, 3.0, and 0.0 mm, respectively, and 93.4% ± 2.1% for the virtual bolus method. Introducing plan uncertainty affects CTV coverage the most when cropping 5.0 mm. When plan uncertainties are considered the methods of cropping 5.0, 3.0 mm, and the virtual bolus method have the same average skin dose within ±0.3%. CONCLUSION This study shows that a virtual bolus planning method results in no increased fluence at the patient's surface, improves CTV coverage, and is the most robust to changes in setup and patient anatomy.
Collapse
Affiliation(s)
- Julie S Kirk
- Medical Physics Department, The Clatterbridge Cancer Centre NHS Foundation Trust, Liverpool, UK
| | - Carl G Rowbottom
- Medical Physics Department, The Clatterbridge Cancer Centre NHS Foundation Trust, Liverpool, UK
- Department of Physics, University of Liverpool, Liverpool, UK
| |
Collapse
|
2
|
Patterson E, Powers M, Metcalfe PE, Cutajar D, Oborn BM, Baines JA. Electron streaming dose measurements and calculations on a 1.5 T MR-Linac. J Appl Clin Med Phys 2024; 25:e14370. [PMID: 38661097 PMCID: PMC11244671 DOI: 10.1002/acm2.14370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 01/04/2024] [Accepted: 04/08/2024] [Indexed: 04/26/2024] Open
Abstract
PURPOSE To evaluate the accuracy of different dosimeters and the treatment planning system (TPS) for assessing the skin dose due to the electron streaming effect (ESE) on a 1.5 T magnetic resonance (MR)-linac. METHOD Skin dose due to the ESE on an MR-linac (Unity, Elekta) was investigated using a solid water phantom rotated 45° in the x-y plane (IEC61217) and centered at the isocenter. The phantom was irradiated with 1 × 1, 3 × 3, 5 × 5, 10 × 10, and 22 × 22 cm2 fields, gantry at 90°. Out-of-field doses (OFDs) deposited by electron streams generated at the entry and exit surface of the angled phantom were measured on the surface of solid water slabs placed ±20.0 cm from the isocenter along the x-direction. A high-resolution MOSkin™ detector served as a benchmark due to its shallower depth of measurement that matches the International Commission on Radiological Protection (ICRP) recommended depth for skin dose assessment (0.07 mm). MOSkin™ doses were compared to EBT3 film, OSLDs, a diamond detector, and the TPS where the experimental setup was modeled using two separate calculation parameters settings: a 0.1 cm dose grid with 0.2% statistical uncertainty (0.1 cm, 0.2%) and a 0.2 cm dose grid with 3.0% statistical uncertainty (0.2 cm, 3.0%). RESULTS OSLD, film, the 0.1 cm, 0.2%, and 0.2 cm, 3.0% TPS ESE doses, underestimated skin doses measured by the MOSkin™ by as much as -75.3%, -7.0%, -24.7%, and -41.9%, respectively. Film results were most similar to MOSkin™ skin dose measurements. CONCLUSIONS These results show that electron streams can deposit significant doses outside the primary field and that dosimeter choice and TPS calculation settings greatly influence the reported readings. Due to the steep dose gradient of the ESE, EBT3 film remains the choice for accurate skin dose assessment in this challenging environment.
Collapse
Affiliation(s)
- Elizabeth Patterson
- Centre for Medical and Radiation PhysicsUniversity of WollongongWollongongNew South WalesAustralia
| | - Marcus Powers
- College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
- Townsville Cancer CentreTownsville Hospital and Health ServiceTownsvilleQueenslandAustralia
| | - Peter E. Metcalfe
- Centre for Medical and Radiation PhysicsUniversity of WollongongWollongongNew South WalesAustralia
- Illawarra Health Medical Research InstituteUniversity of WollongongWollongongNew South WalesAustralia
| | - Dean Cutajar
- Centre for Medical and Radiation PhysicsUniversity of WollongongWollongongNew South WalesAustralia
- Department of Radiation OncologySt George Cancer Care CentreWollongongNew South WalesAustralia
| | - Bradley M. Oborn
- Centre for Medical and Radiation PhysicsUniversity of WollongongWollongongNew South WalesAustralia
- Institute of Radiooncology‐ OncoRayHelmholtz‐Zentrum Dresden‐Rossendorf, RadiooncologyDresdenGermany
- Illawarra Cancer Care CentreWollongong HospitalWollongongNew South WalesAustralia
| | - John A. Baines
- College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
- Townsville Cancer CentreTownsville Hospital and Health ServiceTownsvilleQueenslandAustralia
| |
Collapse
|
3
|
Han H, Geng C, Deng X, Li J, Shu D, Tang X. A preliminary study of multispectral Cherenkov imaging and a Fricke-xylenol orange gel film (MCIFF) for online, absolute dose measurement. Med Phys 2024; 51:3734-3745. [PMID: 38224326 DOI: 10.1002/mp.16942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/17/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024] Open
Abstract
BACKGROUND Cherenkov luminescence imaging has shown potential for relative dose distribution and field verification in radiation therapy. However, to date, limited research utilizing Cherenkov luminescence for absolute dose calibration has been conducted owing to uncertainties arising from camera positioning and tissue surface optical properties. PURPOSE This paper introduces a novel approach to multispectral Cherenkov luminescence imaging combined with Fricke-xylenol orange gel (FXG) film, termed MCIFF, which can enable online full-field absolute dose measurement. By integrating these two approaches, MCIFF allows for calibration of the ratio between two spectral intensities with absorbed dose, thereby enabling absolute dose measurement. METHODS All experiments are conducted on a Varian Clinac 23EX, utilizing an electron multiplying charge-coupled device (EMCCD) camera and a two-way image splitter for simultaneous capture of two-spectral Cherenkov imaging. In the first part of this study, the absorbance curves of the prepared FXG film, which receives different doses, are measured using a fluorescence spectrophotometer to verify the correlation between absorbance and dose. In the second part, the FXG film is positioned directly under the radiation beam to corroborate the dose measurement capacity of MCIFF across various beams. In the third part, the feasibility of MCIFF is tested in actual radiotherapy settings via a humanoid model, demonstrating its versatility with various radiotherapy materials. RESULTS The results of this study indicate that the logarithmic ratios of spectral intensities at wavelengths of 550 ± 50 and 700 ± 100 nm accurately reflect variations in radiation dose (R2 > 0.96) across different radiation beams, particle energies, and dose rates. The slopes of the fitting lines remain consistent under varying beam conditions, with discrepancies of less than 8%. The optical profiles obtained using the MCIFF exhibit a satisfactory level of agreement with the measured results derived from the treatment planning system (TPS) and EBT3 films. Specifically, for photon beams, the lateral distances between the 80% and 20% isodose lines, referred to as the penumbra (P80-20) values, obtained through TPS, EBT3 films, and MCIFF, are determined as 0.537, 0.664, and 0.848 cm, respectively. Similarly, for electron beams, the P80-20 values obtained through TPS, EBT3 films, and MCIFF are found to be 0.432, 0.561, and 0.634 cm, respectively. Furthermore, imaging of the anthropomorphic phantom demonstrates the practical application of MCIFF in real radiotherapy environments. CONCLUSION By combining an FXG film with Cherenkov luminescence imaging, MCIFF can calibrate Cherenkov luminescence to absorbed dose, filling the gap in online 2D absolute dose measurement methods in clinical practice, and providing a new direction for the clinical application of optical imaging to radiation therapy.
Collapse
Affiliation(s)
- Haonan Han
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Changran Geng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautic, Nanjing University of Aeronautics and Astronautics, Ministry of Industry and Information Technology, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xinping Deng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Jun Li
- Radiotherapy Center, Subei People's Hospital of Jiangsu Province, Yangzhou, People's Republic of China
| | - Diyun Shu
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xiaobin Tang
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautic, Nanjing University of Aeronautics and Astronautics, Ministry of Industry and Information Technology, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| |
Collapse
|
4
|
Episkopakis A, Margaroni V, Kanellopoulou S, Marinos N, Koutsouveli E, Karaiskos P, Pappas EP. Dose-response dependencies of OSL dosimeters in conventional linacs and 1.5T MR-linacs: an experimental and Monte Carlo study. Phys Med Biol 2023; 68:225002. [PMID: 37857285 DOI: 10.1088/1361-6560/ad051e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/19/2023] [Indexed: 10/21/2023]
Abstract
Objective. This work focuses on the optically stimulated luminescence dosimetry (OSLD) dose-response characterization, with emphasis on 1.5T MR-Linacs.Approach. Throughout this study, the nanoDots OSLDs (Landauer, USA) were considered. In groups of three, the mean OSLD response was measured in a conventional linac and an MR-Linac under various irradiation conditions to investigate (i) dose-response linearity with and without the 1.5T magnetic field, (ii) signal fading rate and its dependencies, (iii) beam quality, detector orientation and dose rate dependencies in a conventional linac, (iii) potential MR imaging related effects on OSLD response and (iv) detector orientation dependence in an MR-Linac. Monte Carlo calculations were performed to further quantify angular dependence after rotating the detector around its central axis parallel to the magnetic field, and determine the magnetic field correction factors,kB,Q,for all cardinal detector orientations.Main results. OSLD dose-response supralinearity in an MR-Linac setting was found to agree within uncertainties with the corresponding one in a conventional linac, for the axial detector orientation investigated. Signal fading rate does not depend on irradiation conditions for the range of 3-30 d considered. OSLD angular (orientation) dependence is more pronounced under the presence of a magnetic field. OSLDs irradiated with and without real-time T2w MR imaging enabled during irradiation yielded the same response within uncertainties.kB,Qvalues were determined for all three cardinal orientations. Corrections needed reached up to 6.4%. However, if OSLDs are calibrated in the axial orientation and then irradiated in an MR-Linac placed again in the axial orientation (perpendicular to the magnetic field), then simulations suggest thatkB,Qcan be considered unity within uncertainties, irrespective of the incident beam angle.Significance. This work contributes towards OSLD dose-response characterization and relevant correction factors availability. OSLDs are suitable for QA checks in MR-based beam gating applications andin vivodosimetry in MR-Linacs.
Collapse
Affiliation(s)
- Anastasios Episkopakis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
- Global Clinical Operations, Elekta Ltd., Fleming way, RH10 99RR Crawley, West Sussex, United Kingdom
| | - Vasiliki Margaroni
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
| | | | - Nikolas Marinos
- Global Clinical Operations, Elekta Ltd., Fleming way, RH10 99RR Crawley, West Sussex, United Kingdom
| | - Efi Koutsouveli
- Medical Physics Department, Hygeia Hospital, Kifissias Avenue & 4 Erythrou Stavrou, Marousi, 151 23 Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
| | - Eleftherios P Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 115 27 Athens, Greece
| |
Collapse
|
5
|
Di X, Geng C, Guo C, Shang Y, Fu H, Han H, Tang X. Enhanced Cherenkov imaging for real-time beam visualization by applying a novel carbon quantum dot sheeting in radiotherapy. Med Phys 2023; 50:1215-1227. [PMID: 36433734 DOI: 10.1002/mp.16121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Cherenkov imaging can be used to visualize the placement of the beam directly on the patient's surface tissue and evaluate the accuracy of treatment planning. However, Cherenkov emission intensity is lower than ambient light. At present, time gating is the only way to realize Cherenkov imaging with ambient light. PURPOSE This study proposes preparing a novel carbon quantum dot (cQD) sheeting to adjust the wavelength of Cherenkov emission to obtain the optimal wavelength meeting the sensitive detection region of the camera, meanwhile the total optical signal is also increased. By combining a specific filter, this approach might help in using lower-cost camera systems without intensifier-coupled to accomplish in vivo monitoring of the surface beam profile on patients with ambient light. METHODS The cQD sheetings were prepared by spin coating and UV curing with different concentrations. All experiments were performed on the Varian VitalBeam system and optical emission was captured using an electron multiplying charge-coupled device (EMCCD) camera. To quantify the optical characteristics and certify the improvement of light intensity as well as signal-to-noise ratio (SNR) of cQD sheeting, the first part of the study was carried out on solid water with 6 and 10 MV photon beams. The second part was carried out on an anthropomorphic phantom to explore the applicability of sheeting when using different radiotherapy materials and the imaging effect of sheeting with the impact of ambient light sources. Additionally, thanks to the narrow emission spectrum of the cQD, a band-pass filter was tested to reduce the effect from environmental lights. RESULTS The experimental results show that the optical intensity collected with sheeting has an excellent linear relationship (R2 > 0.99) with the dose for 6 and 10 MV photons. The full-width half maximum (FWHM) in x and y axis matched with the measured EBT film image, with accuracy in the range of ±1.2 and ±2.7 mm standard deviation, respectively. CQD sheeting can significantly improve the light intensity and SNR of optical images. Using 0.1 mg/ml sheeting as an example, the signal intensity is increased by 209%, and the SNR is increased by 147.71% at 6 MV photons. The imaging on the anthropomorphic phantom verified that cQD sheeting could be applied to different radiotherapy materials. The average optical intensity increased by about 69.25%, 63.72%, and 61.78%, respectively, after adding cQD sheeting to bolus, mask sample and the combination of bolus and mask. Corresponding SNR is improved by about 62.78%, 56.77%, and 68.80%, respectively. Through the sheeting, optical images with SNR > 5 can be obtained in the presence of ambient light and it can be improved through combining with a band-pass filter. When red ambient lights are on, the SNR is increased by about 98.85% after adding a specific filter. CONCLUSION Through a combination of cQD sheeting and corresponding filter, light intensity and SNR of optical images can be increased significantly, and it shed new light on the promotion of the clinical application of optical imaging to visualize the beam in radiotherapy.
Collapse
Affiliation(s)
- Xing Di
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Changran Geng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China.,Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Chang Guo
- Department of Radiation Oncology, Jiangsu Cancer Hospital, Nanjing, People's Republic of China
| | - Yufen Shang
- Department of Radiation Physics, Dezhou Second People's Hospital, Dezhou, People's Republic of China
| | - Hongtao Fu
- Department of Radiation Physics, Dezhou Second People's Hospital, Dezhou, People's Republic of China
| | - Haonan Han
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xiaobin Tang
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China.,Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| |
Collapse
|
6
|
Alexander DA, Certa O, Haertter A, Li T, Taunk N, Zhu TC. Comparison of surface dose during whole breast radiation therapy on Halcyon and TrueBeam using Cherenkov imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2023; 12371:1237108. [PMID: 37101538 PMCID: PMC10128868 DOI: 10.1117/12.2652588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
The emergence of the Halcyon linear accelerator has allowed for increased patient throughput and improved treatment times for common treatment sites in radiation oncology. However, it has been shown that this can lead to increased surface dose in sites like breast cancer compared with treatments on conventional machines with flattened radiation beams. Cherenkov imaging can be used to estimate surface dose by detection of Cherenkov photons emitted in proportion to energy deposition from high energy electrons in tissue. Phantom studies were performed with both square beams in reference conditions and with clinical treatments, and dosimeter readings and Cherenkov images report higher surface dose (25% for flat phantom entrance dose, 5.9% for breast phantom treatment) from Halcyon beam deliveries than for equivalent deliveries from a TrueBeam linac. Additionally, the first Cherenkov images of a patient treated with Halcyon were acquired, and superficial dose was estimated.
Collapse
Affiliation(s)
- Daniel A. Alexander
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Olivia Certa
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Allison Haertter
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Taoran Li
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Neil Taunk
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| | - Timothy C. Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104
| |
Collapse
|
7
|
Shin DS, Kim TH, Rah JE, Lee SB, Lim YK, Jeong J, Kim H, Shin D, Son J. Flexible real-time skin dosimeter based on a thin-film copper indium gallium selenide solar cell for electron radiation therapy. Med Phys 2022; 50:2402-2416. [PMID: 36583513 DOI: 10.1002/mp.16191] [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: 04/20/2022] [Revised: 11/20/2022] [Accepted: 12/13/2022] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Various dosimeters have been proposed for skin dosimetry in electron radiotherapy. However, one main drawback of these skin dosimeters is their lack of flexibility, which could make accurate dose measurements challenging due to air gaps between a curved patient surface and dosimeter. Therefore, the purpose of this study is to suggest a novel flexible skin dosimeter based on a thin-film copper indium gallium selenide (CIGS) solar cell, and to evaluate its dosimetric characteristics. METHODS The CIGS solar cell dosimeter consisted of (a) a customized thin-film CIGS solar cell and (b) a data acquisition (DAQ) system. The CIGS solar cell with a thickness of 0.33 mm was customized to a size of 10 × 10 mm2 . This customized solar cell plays a role in converting therapeutic electron radiation into electrical signals. The DAQ system was composed of a voltage amplifier with a gain of 1000, a voltage input module, a DAQ chassis, and an in-house software. This system converted the electrical analog signals (from solar cell) to digital signals with a sampling rate of ≤50 kHz and then quantified/visualized the digital signals in real time. We quantified the linearity/ sampling rate effect/dose rate dependence/energy dependence/field size output factor/reproducibility/curvature/bending recoverability/angular dependence of the CIGS solar cell dosimeter in therapeutic electron beams. To evaluate clinical feasibility, we measured the skin point doses by attaching the CIGS solar cell to an anthropomorphic phantom surface (for forehead, mouth, and thorax). The CIGS-measured doses were compared with calculated doses (by treatment planning system) and measured doses (by optically stimulated luminescent dosimeter). RESULTS The normalized signals of the solar cell dosimeter increased linearly as the delivered dose increased. The gradient of the linearly fitted line was 1.00 with an R-square of 0.9999. The sampling rates (2, 10, and 50 kHz) of the solar cell dosimeter showed good performance even at low doses (<50 cGy). The solar cell dosimeter exhibited dose rate independence within 1% and energy independence within 3% error margins. The signals of the solar cell dosimeter were similar (<1%) when penetrating the same side of the CIGS cell regardless of the rotation angle of the solar cell. The field size output factor measured by the solar cell dosimeter was comparable to that measured by the ion chamber. The solar cell signals were similar between the baseline (week 1) and the last time point (week 4). Our detector showed curvature independence within 1.8% (curvatures of <0.10 mm- ) and bending recovery (curvature of 0.10 mm-1 ). The differences between measured doses (CIGS solar cell dosimeter vs. optically stimulated luminescent dosimeter) were 7.1%, 9.6%, and 1.0% for forehead, mouth, and thorax, respectively. CONCLUSION We present the construction of a flexible skin dosimeter based on a CIGS solar cell. Our findings demonstrate that the CIGS solar cell has a potential to be a novel flexible skin dosimeter for electron radiotherapy. Moreover, this dosimeter is manufactured with low cost and can be easily customized to various size/shape, which represents advantages over other dosimeters.
Collapse
Affiliation(s)
- Dong-Seok Shin
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Tae-Ho Kim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Jeong-Eun Rah
- Department of Radiation Oncology, Myongji Hospital, Goyang, Republic of Korea
| | - Se Byeong Lee
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Young Kyung Lim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Jonghwi Jeong
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Haksoo Kim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Dongho Shin
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Jaeman Son
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea
| |
Collapse
|
8
|
Jung S, Kim JI, Park JM, Wu HG, Choi CH. Gold coated contact lens-type ocular in vivo dosimeter (CLOD) for monitoring of low dose in computed tomography: A Monte Carlo study. Phys Med 2021; 92:1-7. [PMID: 34781119 DOI: 10.1016/j.ejmp.2021.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 10/06/2021] [Accepted: 10/28/2021] [Indexed: 10/19/2022] Open
Abstract
PURPOSE This study reports a sensitivity enhancement of gold-coated contact lens-type ocular in vivo dosimeters (CLODs) for low-dose measurements in computed tomography (CT). METHODS Monte Carlo (MC) simulations were conducted to evaluate the dose enhancement from the gold (Au) layers on the CLODs. The human eye and CLODs were modeled, and the X-ray tube voltages were defined as 80, 120, and 140 kVp. The thickness of the Au layer attached to a CLOD ranged from 100 nm to 10 μm. The thickness of the active layer ranged from 20 to 140 μm. The dose ratio between the active layer of the Au-coated CLOD and a CLOD without a layer, i.e., the dose enhancement factor (DEF), was calculated. RESULTS The DEFs of the first 20-μm thick active layer of the 5-μm thick Au-coated CLOD were 18.4, 19.7, 20.2 at 80, 120, and 140 kVp, respectively. The DEFs decreased as the thickness of the active layer increased. The DEFs of 100-nm to 5-μm thick Au layers increased from 1.7 to 5.4 for 120-kVp X-ray tube voltage when the thickness of the active layer was 140 μm. CONCLUSIONS The MC results presented a higher sensitivity of Au-coated CLODs (∼20-times higher than that of CLODs without a gold layer). Au-coated CLODs can be applied to an evaluation of very low doses (a few cGy) delivered to patients during CT imaging.
Collapse
Affiliation(s)
- Seongmoon Jung
- 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
| | - 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
| | - 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; Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Robotics Research Laboratory for Extreme Environments, Advanced Institute of Convergence Technology, Suwon 16229, 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; Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Radiation Oncology, Seoul National University College of Medicine, 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.
| |
Collapse
|
9
|
3D Dosimetry Based on LiMgPO 4 OSL Silicone Foils: Facilitating the Verification of Eye-Ball Cancer Proton Radiotherapy. SENSORS 2021; 21:s21186015. [PMID: 34577220 PMCID: PMC8469107 DOI: 10.3390/s21186015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/27/2021] [Accepted: 09/02/2021] [Indexed: 11/24/2022]
Abstract
A direct verification of the three-dimensional (3D) proton clinical treatment plan prepared for tumor in the eyeball, using the Eclipse Ocular Proton Planning system (by Varian Medical Systems), has been presented. To achieve this, a prototype of the innovative two-dimensional (2D) circular silicone foils, made of a polymer with the embedded optically stimulated luminescence (OSL) material in powder form (LiMgPO4), and a self-developed optical imaging system, consisting of an illuminating light source and a high-sensitive CCD camera has been applied. A specially designed lifelike eyeball phantom has been used, constructed from 40 flat sheet LMP-based silicone foils stacked and placed together behind a spherical phantom made by polystyrene, all to reflect the curvature of the real eyeball. Two-dimensional OSL signals were captured and further analyzed from each single silicone foil after irradiation using a dedicated patient collimator and a 58.8 MeV modulated proton beam. The reconstructed 3D proton depth dose distribution matches very well with the clinical treatment plan, allowing for the consideration of the new OSL system for further 3D dosimetry applications within the proton radiotherapy area.
Collapse
|
10
|
Surface dose and build-up region depth dose measurements in non-standard beams of Cyberknife and tomotherapy systems. Radiol Phys Technol 2021; 14:309-317. [PMID: 34224082 DOI: 10.1007/s12194-021-00629-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to measure the surface dose and build-up region depth dose characteristics of 6 MV photon beams in Cyberknife and helical tomotherapy (HT) systems for non-standard small fields using parallel plate chambers (Roos and Markus), Gafchromic EBT3 films, and nanoDot optically stimulated luminescence dosimeters (OSLDs), as well as to investigate the effect of oblique incidence on the surface dose of the beam. All measurements were conducted in a virtual water phantom under machine-specific reference conditions. The Roos and OSLDs overestimated the surface dose when compared with the Markus chamber and EBT3 films by 20%. We applied water equivalent thickness (WET) correction to account for the intrinsic build-up thickness of the detectors from their effective point of measurement (EPOM). With WET correction, a reasonably close surface dose estimate was obtained for all detectors, within 1.9% agreement for the 60 mm collimator of Cyberknife and 3.1% agreement for the HT system, with a 5 × 10 cm2 field size. The surface dose increased from the normally incident Cyberknife and HT fields with increasing angle of incidence. The surface dose increased to twice its value at normal incidence for highly oblique angles of incidence above 55°. For the tested fields, a reasonable surface dose estimate could be measured with the detectors if the correction for intrinsic buildup thickness was applied. Nevertheless, the use of Roos chambers with large dimensions and nanoDot OSLDs is not recommended for estimating the surface dose for small fields.
Collapse
|
11
|
Zhang Y, Yan S, Cui Z, Wang Y, Li Z, Yin Y, Li B, Quan H, Zhu J. Out-of-field dose assessment for a 1.5 T MR-Linac with optically stimulated luminescence dosimeters. Med Phys 2021; 48:4027-4037. [PMID: 33714229 PMCID: PMC8360091 DOI: 10.1002/mp.14839] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/04/2021] [Accepted: 03/04/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To assess the out-of-field surface and internal dose of the 1.5 T MR-Linac compared to the conventional external beam linac using optically stimulated luminescence dosimeters (OSLDs), and evaluate the out-of-field dose calculation accuracy of the Monaco treatment planning system (TPS) of the 1.5T MR-Linac. METHODS A cubic solid water phantom, with OSLDs on the surface, was vertically irradiated by MR-Linac square fields with different sizes. In addition, OSLDs were arranged out of the beam edges in four directions. An anthropomorphic adult phantom, with 125 cm3 simulated volume, was irradiated in four orthogonal directions by both MR-Linac and conventional linac at the head, thoracic, and pelvic sites. Out-of-field doses were measured by OSLDs on both the surface and internal emulational organs at risk (OARs). The results were compared to the simulated dose from Monaco TPS. RESULTS At different field sizes (5 × 5 to 20 × 20 cm2 ) and distances (1 to 10 cm) to beam edge, the out-of-field surface dose measured on MR-Linac varied from 0.16 % (10 cm to 5 × 5 cm2 edge) to 7.02 % (1 cm to 20 × 20 cm2 edge) of the maximum dose laterally and from 0.14 % (10 cm to 5 × 5 cm2 edge) to 8.56 % (1 cm to 20 × 20 cm2 edge) of the maximum dose longitudinally. Compared to the OSLDs measured data, the Monaco TPS presented an overestimate of the out-of-field dose of OARs at 0-2 % isodose area on both surface and internal check points, and the overestimation gets greater as the distance increases. The underestimation was found to be 0-35% at 2-5% isodose area on both surface and internal check points. Compared to the conventional linac, MR-Linac delivered higher average values of out-of-field dose on surface check points (20%, 19%, 21%) and internal simulated OARs (42%, 37%, 9%) of the anthropomorphic phantom at head, thoracic, and pelvic irradiations, respectively. CONCLUSIONS Compared to the conventional linac, MR-Linac has the same out-of-field dose distribution. However, considering the absolute dose values, MR-Linac delivered relatively higher out-of-field doses on both surface and internal OARs. Additional radiation shielding to patients undergoing MR-Linac may provide protection from out-of-field exposure.
Collapse
Affiliation(s)
- Yan Zhang
- School of Physics and Technology, Wuhan University, Wuhan, P.R. China.,Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Shaojie Yan
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China.,School of Nuclear Science and Technology, University of South China, Hengyang, P.R. China
| | - Zhen Cui
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Yungang Wang
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Zhenjiang Li
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Yong Yin
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Baosheng Li
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Hong Quan
- School of Physics and Technology, Wuhan University, Wuhan, P.R. China
| | - Jian Zhu
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China.,Shandong Medical Imaging and Radiotherapy Engineering Center, Jinan, P.R. China.,Shandong Key Laboratory of Digital Medicine and Computer Assisted Surgery, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China
| |
Collapse
|
12
|
Nguyen THT, Yokoyama H, Kojima H, Isomura N, Takemura A, Ueda S, Noto K. Effect of an integral quality monitor on 4-, 6-, 10-MV, and 6-MV flattening filter-free photon beams. J Appl Clin Med Phys 2020; 22:76-91. [PMID: 33270985 PMCID: PMC7856493 DOI: 10.1002/acm2.13106] [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: 06/01/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 12/04/2022] Open
Abstract
Purpose To investigate the effect of an integral quality monitor (IQM; iRT Systems GmbH, Koblenz, Germany) on 4, 6, 10, and 6‐MV flattening filter‐free (FFF) photon beams. Methods We assessed surface dose, PDD20,10, TPR20,10, PDD curves, inline and crossline profiles, transmission factor, and output factor with and without the IQM. PDD, transmission factor, and output factor were measured for square fields of 3, 5, 10, 15, 20, 25, and 30 cm and profiles were performed for square fields of 3, 5, 10, 20, and 30 cm at 5‐, 10‐, and 30‐cm depth. Results The differences in surface dose of all energies for square fields of 3, 5, 10, 15, 20, and 25 cm were within 3.7% whereas for a square field of 30 cm, they were 4.6%, 6.8%, 6.7%, and 8.7% for 4‐MV, 6‐MV, 6‐MV‐FFF, and 10‐MV, respectively. Differences in PDD20,10, TPR20,10, PDD, profiles, and output factors were within ±1%. Local and global gamma values (2%/2 mm) were below 1 for PDD beyond dmax and inline/crossline profiles in the central beam region, respectively. The gamma passing rates (10% threshold) for PDD curves and profiles were above 95% at 2%/2 mm. The transmission factors for 4‐MV, 6‐MV, 6‐MV‐FFF, and 10‐MV for field sizes from 3 × 3 to 30 × 30 cm2 were 0.926–0.933, 0.937–0.941, 0.937–0.939, and 0.949–0.953, respectively. Conclusions The influence of the IQM on the beam quality (in particular 4‐MV X‐ray has not verified before) was tested and introduced a slight beam perturbation at the surface and build‐up region and the edge of the crossline/inline profiles. To use IQM in pre‐ and intra‐treatment quality assurance, a tray factor should be put into treatment planning systems for the dose calculation for the 4‐, 6‐, 10‐, and 6‐MV flattening filter‐free photon beams to compensate the beam attenuation of the IQM detector.
Collapse
Affiliation(s)
- Trang Hong Thi Nguyen
- Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Haruna Yokoyama
- Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Japan
| | - Hironori Kojima
- Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Japan
| | - Naoki Isomura
- Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Japan
| | - Akihiro Takemura
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Shinichi Ueda
- Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Japan
| | - Kimiya Noto
- Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Japan
| |
Collapse
|
13
|
Verification using in vivo optically stimulated luminescent dosimetry of the predicted skin surface dose in patients receiving postmastectomy radiotherapy. Med Dosim 2020; 46:e1-e6. [PMID: 33941320 DOI: 10.1016/j.meddos.2020.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/14/2020] [Accepted: 10/01/2020] [Indexed: 11/21/2022]
Abstract
The purpose of this study was to evaluate whether dose to the skin surface underneath bolus, was accurately predicted by a 3D treatment planning system (TPS) in patients receiving 50 Gy/25# postmastectomy radiotherapy (PMRT) using optically stimulated luminescent dosimetry (OSLD) for verification. In vivo dosimetry using OSLDs was performed in 20 consecutive patients receiving PMRT. An array of 9 OSLDs were applied to the chest wall or neobreast in a grid arrangement. Dosimetry data were recorded on 3 separate treatment fractions, averaged, and extrapolated to 25 fractions. On the 3D TPS, the predicted dose was calculated using the departmental planning algorithm at points corresponding to the OSLDs. The mean within patient difference between the planned and measured dose at each of the 9 points was calculated and Bland-Altman limits of agreement used to quantify the extent of agreement. Paired t-tests were used to test for evidence of systematic bias at each point. The coefficient of variation of the 3 OSLD readings per patient at each of the 9 points was low for 8 points (≤4.4%) demonstrating comparable dose received per fraction at these points. The mean ratio between the in vivo measured extrapolated OSLD (IVME OSLD) dose and the planned TPS dose ranged between 0.97 and 0.99 across all points (standard deviation range 0.05 to 0.08). The mean within patient difference between the IVME OSLD and planned TPS was <1 Gy at 7 of the 9 points and the t-test for evidence of systematic bias was significant (p = 0.03) at only 1 of the 9 points. Our commercially available 3D TPS closely predicted PMRT skin surface dose underneath bolus as verified by OSLDs. At all sites, the average ratio of delivered to predicted dose was >0.97 but <1. This practical and feasible OSLD assessment of only 3 of 25 fractions facilitates quality assurance of a TPS in predicting skin surface dose under bolus.
Collapse
|
14
|
Tendler II, Bruza P, Jermyn M, Soter J, Sharp G, Williams B, Jarvis LA, Pogue B, Gladstone DJ. Technical Note: A novel dosimeter improves total skin electron therapy surface dosimetry workflow. J Appl Clin Med Phys 2020; 21:158-162. [PMID: 32306551 PMCID: PMC7324701 DOI: 10.1002/acm2.12880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 01/15/2023] Open
Abstract
PURPOSE The novel scintillator-based system described in this study is capable of accurately and remotely measuring surface dose during Total Skin Electron Therapy (TSET); this dosimeter does not require post-exposure processing or annealing and has been shown to be re-usable, resistant to radiation damage, have minimal impact on surface dose, and reduce chances of operator error compared to existing technologies e.g. optically stimulated luminescence detector (OSLD). The purpose of this study was to quantitatively analyze the workflow required to measure surface dose using this new scintillator dosimeter and compare it to that of standard OSLDs. METHODS Disc-shaped scintillators were attached to a flat-faced phantom and a patient undergoing TSET. Light emission from these plastic discs was captured using a time-gated, intensified, camera during irradiation and converted to dose using an external calibration factor. Time required to complete each step (daily QA, dosimeter preparation, attachment, removal, registration, and readout) of the scintillator and OSLD surface dosimetry workflows was tracked. RESULTS In phantoms, scintillators and OSLDs surface doses agreed within 3% for all data points. During patient imaging it was found that surface dose measured by OSLD and scintillator agreed within 5% and 3% for 35/35 and 32/35 dosimetry sites, respectively. The end-to-end time required to measure surface dose during phantom experiments for a single dosimeter was 78 and 202 sec for scintillator and OSL dosimeters, respectively. During patient treatment, surface dose was assessed at 7 different body locations by scintillator and OSL dosimeters in 386 and 754 sec, respectively. CONCLUSION Scintillators have been shown to report dose nearly twice as fast as OSLDs with substantially less manual work and reduced chances of human error. Scintillator dose measurements are automatically saved to an electronic patient file and images contain a permanent record of the dose delivered during treatment.
Collapse
Affiliation(s)
| | - Petr Bruza
- Thayer School of EngineeringDartmouth CollegeHanoverNHUSA
| | - Michael Jermyn
- Thayer School of EngineeringDartmouth CollegeHanoverNHUSA
- DoseOptics LLCLebanonNHUSA
| | - Jennifer Soter
- Thayer School of EngineeringDartmouth CollegeHanoverNHUSA
| | - Gregory Sharp
- Department of Radiation OncologyMassachusetts General HospitalBostonMAUSA
| | - Benjamin Williams
- Department of MedicineGeisel School of MedicineDartmouth CollegeHanoverNHUSA
- Norris Cotton Cancer CenterDartmouth‐Hitchcock Medical CenterLebanonNHUSA
| | - Lesley A. Jarvis
- Department of MedicineGeisel School of MedicineDartmouth CollegeHanoverNHUSA
- Norris Cotton Cancer CenterDartmouth‐Hitchcock Medical CenterLebanonNHUSA
| | - Brian Pogue
- Thayer School of EngineeringDartmouth CollegeHanoverNHUSA
- DoseOptics LLCLebanonNHUSA
| | - David J. Gladstone
- Thayer School of EngineeringDartmouth CollegeHanoverNHUSA
- Department of MedicineGeisel School of MedicineDartmouth CollegeHanoverNHUSA
- Norris Cotton Cancer CenterDartmouth‐Hitchcock Medical CenterLebanonNHUSA
| |
Collapse
|
15
|
Lim-Reinders S, Keller BM, Sahgal A, Chugh B, Kim A. Measurement of surface dose in an MR-Linac with optically stimulated luminescence dosimeters for IMRT beam geometries. Med Phys 2020; 47:3133-3142. [PMID: 32302010 DOI: 10.1002/mp.14185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/24/2020] [Accepted: 04/01/2020] [Indexed: 12/31/2022] Open
Abstract
PURPOSE This study aims to measure the surface dose on an anthropomorphic phantom for intensity-modulated radiation therapy (IMRT) plans treated in a 1.5 T magnetic resonance (MR)-Linac. Previous studies have used Monte Carlo programs to simulate surface dose and have recognized high surface dose as a potential limiting factor for the MR-Linac; however, to our knowledge surface dose measurement for clinical plans has not yet been published. Given the novelty of the MR-Linac, it is important to perform in vivo measurements of a potentially dose-limiting factor such as surface dose when moving forward for clinical use. METHODS Optically stimulated luminescence dosimeters (OSLDs) were used on an anthropomorphic phantom. Intensity-modulated radiation therapy plans were generated to treat a near-surface breast tumor in the phantom. The tumor was treated with 2, 3, 5, 7, and 9 beam IMRT plans with a 1.5 T MR-Linac using a 7-MV photon beam. The plans were generated in a Monte Carlo treatment planning system (TPS) capable of modeling magnetic field effects. The surface dose was sampled in seven locations on the surface surrounding the planning target volume (PTV), and in two different OSLD configurations with the dosimeters measuring water equivalent depths of 0.16 and 0.64 mm. The TPS was used to estimate the doses at the OSLD locations. In addition, MR images were taken of a pork belly with and without an OSLD placed anteriorly placed to determine the effect of an OSLD on image fidelity. RESULTS For the 3, 5, 7, and 9-beam configurations, surface doses were approximately half that of the prescription dose to the simulated tumor, although the magnitude of the skin dose relative to the prescription is certainly also dependent on individual patient anatomy. The general trend for both TPS and measurements was that the greater the number of beams, the lower the skin doses and dose readings; also, with increasing numbers of beams, doses at shallow depths become lower relative to deeper depths. The MR images showed that the presence of the OSLD did not induce clinically relevant geometric distortions or intensity differences. CONCLUSIONS To our knowledge, this study is the first of its kind to experimentally measure the surface dose in an MR-Linac for IMRT plans. This study has explored the use of OSLDs to measure in vivo surface dose in a clinical setting. OSLDs may be used to measure skin dose clinically when there are concerns of skin radiation burns and near-surface toxicity. Optically stimulated luminescence dosimeters are promising devices for in vivo surface dosimetry in an MR-Linac.
Collapse
Affiliation(s)
- Stephanie Lim-Reinders
- Sunnybrook Health Sciences Centre/Odette Cancer Centre, 2075 Bayview Ave, Toronto, ON, M4N 3M5, Canada.,Faculty of Medicine, Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Brian M Keller
- Faculty of Medicine, Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.,Department of Radiation Oncology, Faculty of Medicine, University of Toronto, 149 College Street, Suite 504, Toronto, ON, M5T 1P5, Canada
| | - Arjun Sahgal
- Faculty of Medicine, Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.,Department of Radiation Oncology, Faculty of Medicine, University of Toronto, 149 College Street, Suite 504, Toronto, ON, M5T 1P5, Canada
| | - Brige Chugh
- Faculty of Medicine, Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.,Department of Radiation Oncology, Faculty of Medicine, University of Toronto, 149 College Street, Suite 504, Toronto, ON, M5T 1P5, Canada
| | - Anthony Kim
- Faculty of Medicine, Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.,Department of Radiation Oncology, Faculty of Medicine, University of Toronto, 149 College Street, Suite 504, Toronto, ON, M5T 1P5, Canada
| |
Collapse
|
16
|
Jursinic PA. Optically stimulated luminescent dosimeters stable response to dose after repeated bleaching. Med Phys 2020; 47:3191-3203. [DOI: 10.1002/mp.14182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/03/2020] [Accepted: 04/05/2020] [Indexed: 11/09/2022] Open
Affiliation(s)
- Paul A. Jursinic
- West Michigan Cancer Center 200 North Park Street Kalamazoo MI 49007 USA
| |
Collapse
|
17
|
Lee J, Ramadan S, Kim A, Alayed Y, Ravi A. Dosimetric impact of tracheostomy devices in head and neck cancer patients. J Appl Clin Med Phys 2020; 21:26-32. [PMID: 32374922 PMCID: PMC7324706 DOI: 10.1002/acm2.12862] [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] [Received: 08/11/2019] [Revised: 02/26/2020] [Accepted: 02/29/2020] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION The tracheostomy site and adjacent skin is at risk for recurrence in head/neck squamous cell cancer patients. The tracheostomy tube is an in situ device located directly over the tracheostomy site and may have clinical implications on the radiation dose delivered to the peristomal region. This study aimed to investigate this effect by comparing the prescribed treatment planning dose with the actual dose in vivo to the peristomal clinical target region. A retrospective, dosimetric study was performed with approval of the institutional research ethics board. METHODS Fifteen patients who had received high-dose radiotherapy to the tracheostomy region with in vivo dose measurements were included. The radiation dose at the skin surface underneath the tracheostomy device was measured using an optically stimulated luminescent dosimeter (OSLD) and was compared with the prescribed dose from the radiation planning system. The effect of the tracheostomy flange and/or soft tissue equivalent bolus on the peristomal dose was calculated. RESULTS AND DISCUSSION Patients with tracheostomy equipment in situ were found to have a 3.7% difference between their prescribed and actual dose. With a tissue equivalent bolus there was a 2.0% difference between predicted and actual. The mean prescribed single fraction dose (mean = 191.8 cGy, SD = 40.18) and OSLD measured dose (mean = 194.02 cGy, SD = 44.3) were found to have no significant difference. However, with the flange excluded from the planning simulation (density = air) target skin dose deviated from predicted by an average of 55.3% (range = 12.4-72.9, SD = 22.5) and volume coverage was not achieved. CONCLUSION In summary, the tracheostomy flange acts like bolus with a twofold increase in the skin surface dose. Changes in the peristomal apparatus from simulation to treatment needs to be considered to ensure that the simulated dose and coverage is achieved.
Collapse
Affiliation(s)
- Justin Lee
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Radiation Oncology, Juravinski Cancer Centre, Hamilton, ON, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Sherif Ramadan
- Department of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Anthony Kim
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Yasir Alayed
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Ananth Ravi
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada.,Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Center, Toronto, ON, Canada
| |
Collapse
|
18
|
Zhuang AH, Olch AJ. A practical method for the reuse of nanoDot OSLDs and predicting sensitivities up to at least 7000 cGy. Med Phys 2020; 47:1481-1488. [PMID: 32009242 DOI: 10.1002/mp.14059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Optically stimulated luminescence dosimeter (OSLDs) are often used to make in vivo dose measurements. Most users calibrate the OSLDs using the software provided by the vendor which typically is intended for doses up to about 300 cGy with an uncertainty of ±5.5%. OSLDs that reach that dose are then discarded, and new ones are purchased and calibrated. A method has been developed for reusing OSLDs and predicting dose sensitivity up to at least 7000 cGy. MATERIALS AND METHODS The nanoDot OSLDs used in this study were routinely used to do in vivo measurements for TBI patients. Instead of using the calibration program provided by the vendor, each nanoDot was bleached to about 100 counts (~0.1 cGy), then calibrated with 50 cGy to produce a sensitivity specific to each nanoDot prior to the patient measurement. NanoDots were read in the hardware mode and the sensitivity factor was applied manually to subsequent patient in-vivo TBI measurements. This was followed by bleaching prior to the next use. The changes of nanoDot sensitivity relative to accumulated dose were analyzed among nine nanoDots. In addition, a method to predict a nanoDot's sensitivity was investigated which aims to reduce the number of sensitivity calibrations while retaining dosimetric accuracy. RESULTS Individual per-use nanodot calibrations were performed up to 7000 cGy for 37 clinical TBI patients. Among the nine nanoDots analyzed in this paper, the sensitivity vs accumulated dose decreased linearly up to about 3000 cGy, with linear fitting curve R2 values above 0.93. After 3000 cGy of accumulated dose, the sensitivity started to plateau and tended to increase by 6000 cGy, with 2nd order polynomial curve R2 values above 0.94. With this finding, an efficient and accurate method to predict nanoDots' sensitivities was developed. With the method applied to the nine OSLDs, a total of 127 sensitivities were predicted and retrospectively compared with measured sensitivities. The predicted sensitivities agreed with measured sensitivities within ±4.0% with an average of -0.8%. CONCLUSIONS This study is the first to demonstrate the reuse of nanoDot OSLDs on numerous patients with accumulated dose up to 7000 cGy. Our nanoDot re-usage methodology is accurate, cost-saving and feasible. A time-saving method is also provided that allows a user to reuse a nanoDot with sensitivities predicted with better accuracy than the 5.5% value provided by the conventional batch calibration method.
Collapse
Affiliation(s)
- Audrey H Zhuang
- Department of Radiation Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Arthur J Olch
- Department of Radiation Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.,Radiation Oncology Program, Children's Hospital Los Angeles, Los Angeles, CA, 90027, USA
| |
Collapse
|
19
|
Kim A, Lim-Reinders S, Ahmad SB, Sahgal A, Keller BM. Surface and near-surface dose measurements at beam entry and exit in a 1.5 T MR-Linac using optically stimulated luminescence dosimeters. ACTA ACUST UNITED AC 2020; 65:045012. [DOI: 10.1088/1361-6560/ab64b6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
20
|
Kry SF, Alvarez P, Cygler JE, DeWerd LA, Howell RM, Meeks S, O'Daniel J, Reft C, Sawakuchi G, Yukihara EG, Mihailidis D. AAPM TG 191: Clinical use of luminescent dosimeters: TLDs and OSLDs. Med Phys 2019; 47:e19-e51. [DOI: 10.1002/mp.13839] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 12/20/2022] Open
Affiliation(s)
- Stephen F. Kry
- The University of Texas MD Anderson Cancer Center Houston TX USA
| | - Paola Alvarez
- The University of Texas MD Anderson Cancer Center Houston TX USA
| | | | | | | | - Sanford Meeks
- University of Florida Health Cancer Center Orlando FL USA
| | | | | | | | | | | |
Collapse
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Tariq M, Gomez C, Riegel AC. Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2019; 11:63-68. [PMID: 33458280 PMCID: PMC7807655 DOI: 10.1016/j.phro.2019.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 11/02/2022]
Abstract
Introduction Studies have suggested that optically stimulated luminescent dosimeters (OSLDs) can be used for in vivo dosimetry of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). Clinical uncertainties such as placement error have not been thoroughly investigated. The purpose of this work was to measure OSLD placement error in a clinical sample and analyze its dosimetric impact. Methods and materials The analysis consisted of three parts: first, quantification of placement error in a clinical sample of 128 patients yielding 293 cone-beam CT (CBCT) with visible OSLDs registered to the treatment plan; Second, correlation of placement error and clinical OSLD measurements; third, simulation of dosimeter placement in the treatment plan and correlation of recalculated dose with placement error. Results In the first analysis, average placement error was 9.7 ± 9.5 mm. In the second analysis, placement error and measured-to-planned dose agreement yielded no correlation (R2 = 0.02) for a subsample of 77 CBCTs of 55 head-and-neck patients. Average placement error was 7.0 ± 6.0 mm. Several factors, including image-guided shifts, introduced uncharacterized uncertainty to the measured-to-planned dose agreement. The third analysis isolated placement error from these other effects. Average dosimetric error was -2.4 ± 19.3%. Simulated dosimetric impact was weakly correlated with placement error (R2 = 0.39). Removing outliers reduced the average dosimetric error to -2.1 ± 10.9%, marginally improving the correlation (R2 = 0.44). Conclusion Placement error can substantially impact measured-to-planned dose agreement of OSLDs in high gradient regions, demonstrating the criticality of accurate dosimeter placement for IMRT and VMAT treatments.
Collapse
Affiliation(s)
- Mahin Tariq
- St. Peter's Health Partners, Albany, NY 12208, United States.,Hofstra University, Hempstead, NY 11549, United States.,Northwell Health, New Hyde Park, NY 11402, United States
| | - Cindy Gomez
- Hofstra University, Hempstead, NY 11549, United States
| | - Adam C Riegel
- Hofstra University, Hempstead, NY 11549, United States.,Northwell Health, New Hyde Park, NY 11402, United States.,Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY 11549, United States
| |
Collapse
|
23
|
Gopalakrishnan Z, Nair RK, Raghukumar P, Menon SV, Bhasi S. Verification of Treatment Planning Algorithms Using Optically Stimulated Luminescent Dosimeters in a Breast Phantom. J Med Phys 2019; 43:264-269. [PMID: 30636852 PMCID: PMC6299750 DOI: 10.4103/jmp.jmp_112_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Aim The aim of this study is to measure and compare the surface dose of treated breast and contralateral breast with the treatment planning system (TPS) calculated dose using calibrated optically stimulated luminescent dosimeter (OSLD) in an indigenous wax breast phantom. Materials and Methods Three-dimensional conformal plans were generated in eclipse TPS v. 13 to treat the left breast of a wax phantom for a prescribed dose of 200 cGy. The plans were calculated using anisotropic analytical algorithm (AAA) and Acuros algorithm with 1-mm grid size. Calibrated OSLDs were used to measure the surface dose of treated and contralateral breasts. Results Large differences were observed between measured and expected doses when OSLDs were read in "reading mode" compared to the "hardware mode." The consistency in the responses of OSLDs was better (deviation <±5%) in the "hardware mode." Reasonable agreement between TPS dose and measured dose was found in regions inside the treatment field of treated breast using OSLDs for both algorithms. OSLD measured doses and TPS doses, for the points where the angle of incidence was almost normal, were in good agreement compared to all other locations where the angle of incidence varied from 45° to 70°. The maximum deviation between measured doses and calculated doses with AAA and with Acuros were 2.2% and-12.38%, respectively, for planning target volume breast, and 76% and 77.51%, respectively, for the opposite breast. Conclusion An independent calibration factor is required before using the OSLDs for in vivo dose measurements. With reference to measured doses using OSLD, the accuracy of skin dose estimation of TPS with AAA was better than with Acuros for both the breasts. In general, a reasonable agreement between TPS doses calculated using AAA and measured doses exists in regions inside treatment field, but unacceptable differences were observed for the points lateral to the opposite breast for both AAA and Acuros.
Collapse
Affiliation(s)
- Zhenia Gopalakrishnan
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - Raghuram K Nair
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - P Raghukumar
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - Sharika V Menon
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - Saju Bhasi
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| |
Collapse
|
24
|
Kesen ND, Akbas U, Koksal C, Bilge H. Investigation of AAA dose calculation algorithm accuracy in surface and buildup region for 6MV photon beam using markus parallel-plate ion chamber. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2019; 27:361-369. [PMID: 30856153 DOI: 10.3233/xst-180489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In radiotherapy, dose distributions are obtained by using dose calculation algorithms that are implanted in treatment planning systems (TPS). This study aims to compare the surface doses of separate field sizes calculated by different version of The Analytical Anisotropic Algorithm (AAA) and measured by the parallel-plate ion chamber that is admitted as the most reliable dosimetry system for the surface region dose measurements. In order to measure the near surface dose, water equivalent solid phantom was used and measurements were made for 6MV photon beam at 100 cm source-detector distance for 5×5, 10×10, and 20×20 cm2 field sizes. AAA 8.9 and AAA 15.1 versions of the Varian Eclipse TPS were used for surface dose calculations by generating beams with separate field sizes. The doses were read by considering the effective buildup thickness of Markus parallel-plate ion chamber. The surface doses using 6 MV photon beams for 10×10 cm2 field size at 0.07 mm were found to be 11.04%, 26.25%, and 19.69% for AAA v8.9, AAA v15.1 and Markus chamber, respectively. It was seen that for both of the AAA versions and Markus parallel-plate ion chamber, increasing field sizes also increase surface dose. For all field sizes, surface dose was lowest by using AAA v8.9 at 0.07 mm. The different versions of the same TPS algorithms may calculate the surface doses distinctively. After upgrading of TPS algorithms, surface doses should be calculated and compared by measurements with different dosimetry systems to better understand their calculation behaviors in the near surface region.
Collapse
Affiliation(s)
- Nazmiye Donmez Kesen
- Division of Medical Physics, Istanbul University Oncology Institute, Istanbul, Turkey
| | - Ugur Akbas
- Division of Medical Physics, Istanbul University Oncology Institute, Istanbul, Turkey
| | - Canan Koksal
- Division of Medical Physics, Istanbul University Oncology Institute, Istanbul, Turkey
| | - Hatice Bilge
- Division of Medical Physics, Istanbul University Oncology Institute, Istanbul, Turkey
| |
Collapse
|
25
|
Joseph K, Rose B, Warkentin H, Yun J, Ghosh S, Tankel K. Peri-anal surface dose in anal canal VMAT radiotherapy. J Med Imaging Radiat Oncol 2018; 62:734-738. [PMID: 29797501 DOI: 10.1111/1754-9485.12748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/22/2018] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Skin bolus may routinely be used in the perineum to build up the surface dose in the treatment of anal cancer (ACC); this may contribute to significant acute skin toxicity. Skin bolus may not be needed with the introduction of modern radiotherapy techniques if these planning techniques would achieve adequate surface dose. Our study is to ascertain if appropriate skin dose can be achieved without the use of bolus when VMAT is used in the treatment of ACC. METHODS The study includes 10 ACC patients treated with VMAT radiotherapy. Optically stimulated luminescence dosimeters (OSLD) are used to evaluate whether the calculated dose for the VMAT planning technique (VMAT-PT) accurately predicted the dose delivered to peri-anal target region without bolus. The OSLD recorded the dose at the anal verge or at the lower most extent of the tumour for each patient over two fractions. The OSLD was read after each of the two fractions, and the average value was reported. The mean dose over a volume centred on the anal marker was calculated in the treatment planning system (TPS). RESULTS The mean TPS-calculated dose was 186.1 cGy. The mean of the OSLD-measured doses was 205.7 cGy for a single fraction. The mean of the measured doses was 10.6% higher than the mean of the calculated doses. CONCLUSIONS The calculated dose for the VMAT-PT consistently under-predicted the dose delivered to the peri-anal target region without bolus. Routine use of skin bolus could be avoided with VMAT-PT when the patient is treated in a supine position.
Collapse
Affiliation(s)
- Kurian Joseph
- Division of Radiation Oncology, Department of Oncology, University of Alberta & Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Brenda Rose
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Heather Warkentin
- Division of Medical Physics, Department of Oncology, University of Alberta & Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Jihyun Yun
- Division of Medical Physics, Department of Oncology, University of Alberta & Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Sunita Ghosh
- Division of Medical Oncology, Department of Oncology, University of Alberta & Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Keith Tankel
- Division of Radiation Oncology, Department of Oncology, University of Alberta & Cross Cancer Institute, Edmonton, Alberta, Canada
| |
Collapse
|
26
|
Cheung JP, Perez-Andujar A, Morin O. Characterization of the effect of a new commercial transmission detector on radiation therapy beams. Pract Radiat Oncol 2017; 7:e559-e567. [PMID: 28666901 DOI: 10.1016/j.prro.2017.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 03/07/2017] [Accepted: 04/05/2017] [Indexed: 10/19/2022]
|
27
|
Vicoroski N, Espinoza A, Duncan M, Oborn BM, Carolan M, Metcalfe P, Menichelli D, Perevertaylo VL, Lerch MLF, Rosenfeld AB, Petasecca M. Development of a silicon diode detector for skin dosimetry in radiotherapy. Med Phys 2017; 44:5402-5412. [DOI: 10.1002/mp.12469] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/14/2017] [Accepted: 06/28/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Nikolina Vicoroski
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Anthony Espinoza
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Mitchell Duncan
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Bradley M. Oborn
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Martin Carolan
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | | | | | - Michael L. F. Lerch
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | - Anatoly B. Rosenfeld
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | - Marco Petasecca
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| |
Collapse
|
28
|
In vivo dosimetry with optically stimulated luminescent dosimeters for conformal and intensity-modulated radiation therapy: A 2-year multicenter cohort study. Pract Radiat Oncol 2017; 7:e135-e144. [DOI: 10.1016/j.prro.2016.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/01/2016] [Accepted: 09/01/2016] [Indexed: 11/19/2022]
|
29
|
Butson M, Chen T, Alzaidi S, Pope D, Butson E, Gorjiara T, Poder J, Cho G, Gill S, Morales J, Haque M, Whitaker M, Hill R. Extrapolated skin dose assessment with optically stimulated luminescent dosimeters. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/4/047001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
30
|
Reynolds TA, Higgins P. Surface dose measurements with commonly used detectors: a consistent thickness correction method. J Appl Clin Med Phys 2015; 16:358–366. [PMID: 26699319 PMCID: PMC5690169 DOI: 10.1120/jacmp.v16i5.5572] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 05/06/2015] [Accepted: 04/29/2015] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to review application of a consistent correction method for the solid state detectors, such as thermoluminescent dosimeters (chips (cTLD) and powder (pTLD)), optically stimulated detectors (both closed (OSL) and open (eOSL)), and radiochromic (EBT2) and radiographic (EDR2) films. In addition, to compare measured surface dose using an extrapolation ionization chamber (PTW 30-360) with other parallel plate chambers RMI-449 (Attix), Capintec PS-033, PTW 30-329 (Markus) and Memorial. Measurements of surface dose for 6MV photons with parallel plate chambers were used to establish a baseline. cTLD, OSLs, EDR2, and EBT2 measurements were corrected using a method which involved irradiation of three dosimeter stacks, followed by linear extrapolation of individual dosimeter measurements to zero thickness. We determined the magnitude of correction for each detector and compared our results against an alternative correction method based on effective thickness. All uncorrected surface dose measurements exhibited overresponse, compared with the extrapolation chamber data, except for the Attix chamber. The closest match was obtained with the Attix chamber (-0.1%), followed by pTLD (0.5%), Capintec (4.5%), Memorial (7.3%), Markus (10%), cTLD (11.8%), eOSL (12.8%), EBT2 (14%), EDR2 (14.8%), and OSL (26%). Application of published ionization chamber corrections brought all the parallel plate results to within 1% of the extrapolation chamber. The extrapolation method corrected all solid-state detector results to within 2% of baseline, except the OSLs. Extrapolation of dose using a simple three-detector stack has been demonstrated to provide thickness corrections for cTLD, eOSLs, EBT2, and EDR2 which can then be used for surface dose measurements. Standard OSLs are not recommended for surface dose measurement. The effective thickness method suffers from the subjectivity inherent in the inclusion of measured percentage depth-dose curves and is not recommended for these types of measurements.
Collapse
Affiliation(s)
- Tatsiana A. Reynolds
- Department of Radiation OncologyUniversity of Minnesota Med School‐Twin CitiesMinneapolisMNUSA
| | - Patrick Higgins
- Department of Radiation OncologyUniversity of Minnesota Med School‐Twin CitiesMinneapolisMNUSA
| |
Collapse
|
31
|
Jursinic PA. Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries. Med Phys 2015; 42:5633-41. [DOI: 10.1118/1.4929558] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
32
|
Kry SF, Olch A, Mohan R. Comment on “Monte Carlo evaluations of the absorbed dose and quality dependence of Al2
O3
in radiotherapy photon beams” [Med. Phys. 36(10), 4421-4424 (2009)]. Med Phys 2015; 42:2648-9. [DOI: 10.1118/1.4914139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|