当前位置： SCI文献检索 > MEDICAL PHYSICS期刊下所有文献 > SU-E-T-118: Characterization of EBT3 Films in Photon and Proton Beams.

SU-E-T-118: Characterization of EBT3 Films in Photon and Proton Beams.

Abstract：

PURPOSE:To measure the calibration curves of EBT3 dosimetry films in photon and proton beams and to quantify the related uncertainties from one beam type to another. METHODS:EBT3 Gafchromic films have similar properties than EBT2 with a symmetric construction and a matte polyester substrate to prevent Newton's ring artefacts. Films from a same batch were exposed in three different beam qualities, an Elekta SL25 6 MV photon beam, a 100 MeV 5×5cm2 proton beam delivered by pencil-beam scanning dedicated system from IBA and a 60 MeV fixed proton beam (2.5cm in diameter) at Clatterbridge Center for Oncology (CCO), UK. The films were read using an EPSON 10000 XL/PRO scanner. Film calibration curves were acquired for all modalities within a range of 0.05 to 20 Gy. Influence of increasing linear-energy transfer (LET) on film response was investigated by comparing dose measured by EBT3 to a silicon diode detector in depth for a fully-modulated beam using the CCO beam line (homogeneous dose with distal end at 3.1cm in water). A comprehensive uncertainty budget (reproducibility, uniformity'¦) was estimated on films irradiated by Elekta SL25. RESULTS:The main source of uncertainty was the non-uniformity of the scanner response. By placing all the irradiated films at the center of the scanner, the uncertainty could be reduced from 5.8% to 1.9% (1 sigma). For all beams and energies, the calibration curves were matched within uncertainties. Along the fully-modulated depth dose curve, diode and EBT3 measurement were in a 4% agreement point-to-point, indicating films weak dependence with LET. CONCLUSIONS:The weak influence of LET, beam type and energy on film response as well as its small uncertainty make EBT3 suitable for relative dosimetry and a promising candidate for measuring correction factors (quality, recombination,'¦) for reference dosimetry with ion chambers of non-standard beams (e.g pencil-beam scanning proton-therapy). â€œThis work is supported by the Walloon Region under the project name InVivoIGT, convention number 1017266.â€.

journal_name

Med Phys

journal_title

Medical physics

authors

Sorriaux J,Rossomme S,Kacperek A,Bertrand D,Vynckier S,Sterpin E

doi

10.1118/1.4735176

subject

Has Abstract

pub_date

2012-06-01 00:00:00

pages

3730

issue

6Part11

eissn

0094-2405

issn

2473-4209

journal_volume

pub_type

杂志文章

在线工具

SU-E-T-118: Characterization of EBT3 Films in Photon and Proton Beams.