52 161

Cited 0 times in

Impact of gamma analysis parameters on dose evaluation using Gafchromic EBT2 films

Lee, SR; Park, JY; Suh, TS; Park, HJ; Lee, JW; Jung, WG
The journal of the Korean Physical Society, 61(8):1319-1324, 2012
Journal Title
The journal of the Korean Physical Society
To recommend optimal gamma analysis parameters (grid size and search range) for detecting dose errors, we evaluated the impact of gamma models and parameters on dose verification in volumetric modulated fields. Delivered doses were verified under open, 45° wedged, and volumetric modulated fields for prostate, anal, head and neck, and brain cancer by using Gafchromic EBT2 films for gamma evaluation. Two gamma models (a conventional method and a modified method to compensate for unintended dose errors caused by misalignments between reference and evaluated matrixes) were employed. The variation in the detected dose errors was evaluated in each gamma model for different grid sizes (0.5, 1, and 2 mm) and search ranges (1, 2, and 4 mm) applied to determine distant-to-agreement. The dose discrepancy of each evaluation was qualitatively and quantitatively evaluated using a pass ratio in analysis software developed in-house. The modified gamma model with a small search range and grid size showed a higher pass ratio than the conventional model in volumetric modulated arc therapy. The pass ratio for 2 mm grid size decreased by over 40% as compared to that for 1 mm grid size. The pass ratio decreased by more than 30% as the search range was increased from 1 mm to 4 mm. Therefore, 1 mm grid size and 1 mm search range may be appropriate to evaluate dose errors in modulated fields after using the modified gamma model.
Film dosimetryGamma evaluationGrid sizeIntensity-modulated fieldSearch range
Appears in Collections:
Journal Papers > School of Medicine / Graduate School of Medicine > Radiation Oncology
AJOU Authors
박, 혜진
Files in This Item:
fulltext not available.txtDownload
RIS (EndNote)
XLS (Excel)


해당 아이템을 이메일로 공유하기 원하시면 인증을 거치시기 바랍니다.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.