Commissioning and Optimization of a Total Skin Electron Therapy Technique Using a High Dose Rate Electron Facility

• 作者: Casper A. Willemse Y. A. M. Yousif
• 来源期刊: 医学物理学、临床工程、放射肿瘤学(英文)
• 学科: 医学
• 关键词: TOTAL SKIN ELECTRON THERAPY MYCOSIS Fungoides High DOSE Rate ELECTRON Monte Carlo Simulation
• 年，卷（期）: 2015,（3）
• 页码范围: 197-207
• 页数: 11页
• 分类号: R73

摘要

Total skin electron therapy (TSET) is used for the treatment of Mycosis Fungoides. Several tech-niques have been developed, in order to achieve homogeneous dose distribution over the complete body surface. To implement a TSET technique, one has to optimize a variety of parameters. Monte Carlo simulation of TSET can facilitate this optimization. The aim of this study was to commission and optimize a TSET technique using the 4 and 6 MeV electron and the high dose rate facility on the Elekta Precise accelerator. The EGS4nrc/BEAMnrc Monte Carlo code was used. The beam data were calculated and measured at two different scoring planes for a single beam. The Model was validated by comparing the simulation with measurements. Two different vertical angles were used to obtain a uniform dose. The angle was optimized for best dose uniformity. The Rando phantom is placed on a rotating platform and rotates 60 degrees apart to facilitate the six patient position orientations. The doses delivered in a phantom by complete treatment were measured with Kodak EDR2 films and TLDs. The dose distribution varied among various scanning directions by 2 - 3 mm and 3 - 4 mm for 4 and 6 MeV respectively. The composite percentage depth dose of all six dual fields for the 4 and 6 MeV yielded an R80 of ~4 mm and ~6 mm, respectively. Dose uniformity was ±6% for 4 MeV and ±5% for 6 MeV. The bremsstrahlung contamination was 0.9% - 1.3%. Good agreements were found with published literature and inline with international protocols.