RBE variation as a function of depth in the 200-MeV proton beam produced at the National Accelerator Centre in Faure (South Africa)
| Autor: | Lothar Böhm, A N Schreuder, Pierre Scalliet, John Gueulette, M Octave-Prignot, J.E. Symons, D. T. L. Jones, B M De Coster, André Wambersie, Stefaan Vynckier |
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| Rok vydání: | 1997 |
| Předmět: |
Male
Proton Sobp Mice Inbred Strains Bragg peak Radiotherapy High-Energy Nuclear physics Mice South Africa Intestinal Neoplasms Relative biological effectiveness Animals Radiology Nuclear Medicine and imaging Irradiation Cobalt Radioisotopes Cobalt-60 Neutrons Physics business.industry Dose-Response Relationship Radiation Hematology Oncology Gamma Rays Female Particle Accelerators Protons Isotopes of cobalt Nuclear medicine business Precancerous Conditions Relative Biological Effectiveness Beam (structure) |
| Zdroj: | Radiotherapy and Oncology. 42:303-309 |
| ISSN: | 0167-8140 |
| DOI: | 10.1016/s0167-8140(97)01919-1 |
| Popis: | BACKGROUND AND PURPOSE: Thorough knowledge of the RBE of clinical proton beams is indispensable for exploiting their full ballistic advantage. Therefore, the RBE of the 200-MeV clinical proton beam produced at the National Accelerator Centre of Faure (South Africa) was measured at different critical points of the depth-dose distribution. MATERIAL AND METHODS: RBEs were determined at the initial plateau of the unmodulated and modulated beam (depth in Perspex = 43.5 mm), and at the beginning, middle and end of a 7-cm spread-out Bragg peak (SOBP) (depths in Perspex = 144.5, 165.5 and 191.5 mm, respectively). The biological system was the regeneration of intestinal crypts in mice after irradiation with a single fraction. RESULTS: Using 60Co gamma-rays as the reference, the RBE values (for a gamma-dose of 14.38 Gy corresponding to 10 regenerated crypts) were found equal to 1.16 +/- 0.04, 1.10 +/- 0.03, 1.18 +/- 0.04, 1.12 +/- 0.03 and 1.23 +/- 0.03, respectively. At all depths, RBEs were found to increase slightly (about 4%) with decreasing dose, in the investigated dose range (12-17 Gy). No significant RBE variation with depth was observed, although RBEs in the SOBP were found to average a higher value (1.18 +/- 0.06) than in the entrance plateau (1.13 +/- 0.04). CONCLUSION: An RBE value slightly larger than the current value of 1.10 should be adopted for clinical application with a 200-MeV proton beam. |
| Databáze: | OpenAIRE |
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