Design of metallic electron beam cones for an intraoperative therapy linear accelerator
| Autor: | F. Krispel, Timothy G. Ochran, Kenneth R. Hogstrom, A. L. Boyer, Tyvin A. Rich, Almon S. Shiu, S.M. Kirsner |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Cancer Research
Electron Linear particle accelerator law.invention Brass Intraoperative Period Radiation Protection Optics law Humans Medicine Dosimetry Radiology Nuclear Medicine and imaging Radiometry Leakage (electronics) Radiation business.industry X-Rays Collimator Oncology visual_art visual_art.visual_art_medium Cathode ray Scattering theory Particle Accelerators Nuclear medicine business |
| Zdroj: | International Journal of Radiation Oncology*Biology*Physics. 18:1223-1232 |
| ISSN: | 0360-3016 |
| DOI: | 10.1016/0360-3016(90)90461-r |
| Popis: | A set of circular collimators and treatment cones from 5 to 12 cm diameter has been designed for an intraoperative accelerator (6–18 MeV) that has an optical docking system. Electron beam scattering theory has been used to minimize their weight while minimizing leakage radiation. Both acrylic and brass were evaluated as possible materials; however, because of substantial electron leakage through the lateral cone wall for acrylic, we have concluded that 2 mm thick brass walls are more desirable than acrylic walls. At 18 MeV, isodose measurements beneath the cones showed hot spots as great as 120% for both materials. The placement and dimension of an internal trimmer ring inside the brass cone was studied as a method for reducing the hot spots, and it was found this could only be accomplished at the expense of decreasing coverage of the 90% isodose surface. The effects of 1° cone misalignment on the dose distribution has been studied and found to generate changes of less than 5% in the dose and 3 mm in position of the 90% isodose surface. In a study of the contribution of the cone and its matching collimator assembly to x-ray room leakage, it was noted that although the treatment cone had a negligible contribution, the upper annuli of the upper collimator assembly contributed as much as 80% of the leakage at 16 MeV for the 5-cm cone. |
| Databáze: | OpenAIRE |
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