| Radiotherapy plays an important role in the cancer treatment, it is necessary to verify the dose distribution of radiation field, in order to assure the quality and effectiveness. Film dosimetry is convenient to use, high special resolution, provides record of the integrated two dimensional dose distributions, never mind the lateral electronic disequilibrium in any phantom. Therefore film dosimetry was able to measure the dose distribution of radiation field, and become an integral part of dose verification for advanced radiotherapy technology, such as intensity mODulated radiation therapy (IMRT), and small field dosimetry like stereotactic radiosurgery.This paper use film dosimeter the dose distribution of radiation field, compared with automatic scanning dose measuring water phantom. Study the electron linac,cobalt-60 therapy unit,stereotactic radiosurgery (gamma knife radiosurgery and X-knife), using KODAK XV,KODAK EDR,GAFCHROMIC EBT, RTS-200s 2D dosimetry system, RFA-300 3D dosimetry system, to measure and analyze two important parameter (full width at half maximum(FWHM), and penumbra) of the dose distribution, estimate the agreement of their obtain values. The result shows that: in test of electron Linac, the maxiMUm absolute deviation of XV, EDR and EBT film compared with RFA-300 is 0.5. 0.3, 0.2mm; in the test of cobalt-60 unit, the maxiMUm absolute deviation of XV,EDR and EBT film compared with RTS-200 is 2.6,1.3,0.7mm; in test of X-Knife, the maxiMUm absolute deviation of XV,EDR and EBT film compared with RFA-300 is 0.3,0.3,0.3mm; in the test of Gamma-Knife, the maxiMUm absolute deviation of EDR and EBT is 0.5mm, but it was 3.7 of XV and EDR. The three films were available and credible dosimetry in measuring and validating the dose distribution, except that XV film not suit for Gamma-Knife.This paper studied application of film dosimetry in measuring dose distribution of radiation field systemically, have high application value in quality control of radiotherapy dose. |
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