Implementation of Small Field Radiotherapy Dosimetry for Spinal Metastase Case

摘要

The main objective of this study was to know dose profile of small field radiotherapy in the spinal metastase case with source axis distance (SAD) techniques. In addition, we evaluated and compared the dose planning of stereotactic body radiation therapy (SBRT) and conventional techniques to measurements with Exradin A16 and Gafchromic EBT3 film dosimeters. The results showed that film EBT3 had a highest precision and accuracy with the average of the standard deviation of ±1.7 and maximum discrepancy of 2.6 %. In addition, the average value of Full Wave Half Maximum (FWHM) and its largest deviation in small field size of 0.8 x 0.8 cm~2 are 0.82 cm and 16.3 % respectively, while it was found around 2.36 cm and 3 % for the field size of 2.4 x 2.4 cm~2. The comparison between penumbra width and the collimation was around of 37.1 % for the field size of 0.8 x 0.8 cm~2, while it was found of 12.4 % for the field size of 2.4 x 2.4 cm~2.