In vivo dosimetry during conformal therapy of prostatic cancer

摘要: Abstract In vivo dose measurements were performed during the simultaneous boost technique for prostatic cancer to check accuracy of calculations by a monitor unit calculation program and three-dimensional planning system. The large field are given simultaneously using customized 10 mm thick Roses-metal blocks in which is cut out. Following procedure quality assurance protocol this technique, at specification point has been determined dosimetry. measured was initially too high 5 out 16 patients, due unexpected differences two beams with same nominal beam different density correction femoral heads; therefore checked improved. also compared CT-based (3-D) system, average deviation 3-D system from 0.1% ± 1.2%. Entrance, midline exit values central axial plane, cranial plane under transmission block have treatment entrance is, on average, 3.4% higher than calculated AP up 5.5% lateral beams. Phantom showed that these not related patient set-up errors. For various points difference between about 0.5%. No systematic deviations found points. resulted mainly change percentage depth tray supporting block. Our results demonstrated every validity be rechecked. Using we able calculate very accurately dose-high precision technique.