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S N, M A, A A, F F, P S. Evaluation of Therapeutic Properties of a Low Energy Electron Beam Plus Spoiler for Local Treatment of Mycosis Fungoides: A Monte Carlo Study. J Biomed Phys Eng 2020; 10:441-448. [PMID: 32802792 PMCID: PMC7416096 DOI: 10.31661/jbpe.v0i0.712] [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: 12/25/2016] [Accepted: 02/10/2017] [Indexed: 11/16/2022]
Abstract
Background: When using low-energy electron beams for the treatment of skin lesions, such as Mycosis Fungoides (MF), a beam spoiler
is used to decrease electron therapeutic depth (R90) while increasing the surface dose. Objective: The aim of this study was to evaluate the characteristics of a 5 MeV electron beam when using a spoiler for the local treatment of MF skin lesions by Monte Carlo (MC) simulation. Material and Methods: In this experimental study, a Siemens Primus treatment head and an acrylic spoiler, positioned at the end of applicator,
were simulated using BEAMnrc, an EGSnrc user code. The modelled beam was validated by measurement using MP3-M water tank,
Roos parallel plate chamber and Semi flex Chamber-31013 (all from PTW, Freiburg, Germany). For different spoiler thicknesses, dose distributions in water were calculated for 2 field sizes and were compared to those for the corresponding open fields. Results: For a 1.3 cm spoiler, therapeutic range changed from 1.5 cm (open field) to 0.5 cm and 0.4 cm for 10 × 10 cm2 and 20 × 20 cm2 field sizes,
respectively. Maximum increase in penumbra width was 2.8 and 3.8 cm for 10 × 10 cm2 and 20 × 20 cm2 field sizes, respectively. Maximum increase in bremsstrahlung contamination was %2 in both field sizes. Conclusion: R90 decreased exponentially with increase in spoiler thickness. The effect of field size on penumbra was much larger for spoiled beam compared to the open beam. The results of this research can be applied to optimize the radiation treatment of MF patients in our hospital.
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Affiliation(s)
- Noshadi S
- MSc, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Atarod M
- PhD, Department of Medical Physics and Radiology, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Amouheidari A
- MD, Department of Radiation Oncology, Milad Hospital, Isfahan, Iran
| | - Felfeliyan F
- MSc, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Shokrani P
- PhD, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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F F, M A, A A, S N, P S. Design and Implementation of a Monte Carlo Framework for Assessment of Spoiler Applications in Abutting Electron Fields. J Biomed Phys Eng 2020; 10:341-348. [PMID: 32637378 PMCID: PMC7321388 DOI: 10.31661/jbpe.v0i0.609] [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: 07/15/2016] [Accepted: 10/08/2016] [Indexed: 11/25/2022]
Abstract
Background: Field matching problems in abutting electron fields can be managed by using spoilers. Objective: The aim of this study was to design a Monte Carlo framework for the assessment of spoiler application in abutting electron fields. Material and Methods: In this experimental study, a Siemens Primus treatment head was simulated for a 5 MeV electron beam using BEAMnrc, DOSXYZnrc and EGSnrc user codes.
Validation of beam model was done by measurement using a MP3-M water tank and a Semi-flex Chamber-31010 (PTW, Freiburg, Germany). An in-house routine
was developed to calculate the combined isodose curves resulting from simulated adjacent fields. The developed framework was analyzed using PMMA and chromium spoilers. Results: The penumbra width increased from 27.5 mm for open fields to 42 mm for PMMA and 40 mm for chromium. The maximum junction dose reduced
from 115% for open fields to 107% for PMMA and 108% for chromium. R90 reduced about 6 mm for PMMA and 3 mm for chromium. Uniformity index
reduced from 93% to 77% for both spoilers. Surface dose increased from 79% to 89% for PMMA and 88% for chromium. Conclusion: Using spoilers, penumbra width at the surface was increased, size and depth of hot spots as well as the therapeutic range were reduced
and dose homogeneity at the junction of abutting electron fields was improved. For both spoilers, the uniformity index reduced, and surface
percent dose increased. The results of this research can be used to optimize dose distribution in electron beam treatment using abutting fields.
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Affiliation(s)
- Felfeliyan F
- MSc, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Atarod M
- PhD, Department of Medical Physics and Radiology, Shahrekord University of Medical Sciences, Shahrekord, Iran 3MD, Department of Radiation Oncology, Milad Hospital, Isfahan, Iran
| | - Amouheidari A
- PhD, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Noshadi S
- MSc, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Shokrani P
- PhD, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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Kim SW, Kim C, Cho MS, Noh S, Lee M, Jeong C, Kwak J, Koh M, Song SY, Lee SW, Soh J, Cho S, Cho B. Clinical implementation of a wide-field electron arc technique with a scatterer for widespread Kaposi's sarcoma in the distal extremities. Sci Rep 2020; 10:9693. [PMID: 32546847 PMCID: PMC7297993 DOI: 10.1038/s41598-020-66846-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 05/27/2020] [Indexed: 11/09/2022] Open
Abstract
A novel wide-field electron arc technique with a scatterer is implemented for widespread Kaposi's sarcoma (KS) in the distal extremities. Monte Carlo beam modeling for electron arc beams was established to achieve <2% deviation from the measurements, and used for dose calculation. MC-based electron arc plan was performed using CT images of a foot and leg mimicking phantom and compared with in-vivo measurement data. We enrolled one patient with recurrent KS on the lower extremities who had been treated with photon radiation therapy. The 4- and 6-MeV electron arc plans were created, and then compared to two photon plans: two opposite photon beam and volumetric modulated arc with bolus. Compared to the two photon techniques, the electron arc plans resulted in superior dose saving to normal organs beneath the skin region, although it shows inferior coverage and homogeneity for PTV. The electron arc treatment technique with scatterer was successfully implemented for the treatment of widespread KS in the distal extremities with lower radiation exposure to the normal organs beyond the skin lesions, which could be a treatment option for recurrent skin cancer in the extremities.
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Affiliation(s)
- Sung-Woo Kim
- Department of Radiation Oncology, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.,Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Changhwan Kim
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Min-Seok Cho
- Department of Radiation Oncology, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.,Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Seonyeong Noh
- Department of Radiation Oncology, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Minsik Lee
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Chiyoung Jeong
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Jungwon Kwak
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Minji Koh
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Si Yeol Song
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
| | - Sang-Wook Lee
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jeongtae Soh
- Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Seungryong Cho
- Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Byungchul Cho
- Department of Radiation Oncology, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. .,Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
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Adjuvance in refractory keloids using electron beams with a spoiler: Recent results. Rep Pract Oncol Radiother 2014; 20:43-9. [PMID: 25535584 DOI: 10.1016/j.rpor.2014.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 05/17/2014] [Accepted: 08/06/2014] [Indexed: 11/22/2022] Open
Abstract
AIM To present clinical results of adjuvant irradiation of excised refractory keloid wounds using a novel bolus-free technique developed within our group to irradiate the skin surface with a linear accelerator. BACKGROUND The use of a bolus to increase surface dose over a newly excised keloid presents several problems. Previous solutions are unsatisfactory. Our technique is promising but needs to be evaluated in practice. MATERIALS AND METHODS Twenty refractory skin keloids in 19 patients were excised and irradiated in Hospital Plató (Barcelona, Spain) using a 6 MeV electron beam with a 4-mm aluminium spoiler. 15 Gy in fractions of 3 Gy were delivered to the excision site plus a safety margin. All patients were examined during the follow-up (median: 40 months, interval: 12-68 months) and toxicities were recovered. RESULTS At the end of the follow-up period, 76% of the cases had not recurred, while the complete response rate amounted to 53%. Residual hypertrophic scars were classified as partial responses. After therapy, itching and pain were observed in 30% of the patients, as well as one telangiectasia and two hyperchromatic scars. CONCLUSION Our technique avoids using a bolus while combining the benefits of electron beam therapy in keloids (fewer secondary effects, and fewer and shorter treatments) with a dose deposition adequate for skin surface treatments. Our results are in line with the most successful therapies evaluated in the literature, as secondary effects are acceptable and recurrence rates are low.
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