Comparison of the Epson Expression 1680 flatbed and the Vidar VXR-16 dosimetry PRO™ film scanners for use in IMRT dosimetry using gafchromic and radiographic film
Comparison of the Epson Expression 1680 flatbed and the Vidar VXR-16 dosimetry PRO™ film scanners for use in IMRT dosimetry using gafchromic and radiographic film
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DOI：
10.1118/1.2402584
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发表时间：
2007-01-01
期刊：
影响因子：
3.8
通讯作者：
Nedialkova, Lucy
中科院分区：
文献类型：
--
作者：
Wilcox, Ellen;Daskalov, George;Nedialkova, Lucy
调强放疗（IMRT）治疗计划的验证通常使用柯达EDR2胶片和Vidar剂量测定PRO （TM）胶片数字化仪完成。然而，由于许多医院正在转向无胶片环境，因此可能无法使用胶片处理器。因此，我们研究了一种新的用于IMRT剂量测定的Gafchromic((R)) EBT薄膜。平面IMRT剂量分布被传送到EBT和EDR2膜上，并用Vidar VXR-16和Epson Expression 1680平板扫描仪进行扫描。然后将测量的剂量分布与Pinnacle治疗计划系统计算的剂量分布进行比较。IMRT治疗包括7-9个6 MV的光束，用于治疗前列腺、头颈部和其他一些部位。采用FilmQA (TM) （3cognition LLC）软件进行分析。测量和计算剂量分布之间的比较报告为剂量差（DID）（像素在+/- 5%以内），一致距离（DTA） （3mm），以及伽马值（gamma）（剂量+/- 3%，dist = 2mm）。使用EDR2和Vidar扫描仪是一种既定的技术，在所有指标（DD、DTA和gamma）中，计算和测量的剂量分布之间的一致性优于90%。然而，在对数模式下，使用Vidar扫描仪进行EBT薄膜扫描时，计算结果的一致性下降到80%以下。线性模式下获得的EBT Vidar扫描显示，在80%的范围内，一致性得到了改善，但在整个扫描过程中仍然观察到伪影。这些伪影在所有EBT扫描中都非常明显，这可以归因于胶片通过扫描仪传输的方式。在爱普生扫描仪中，两种薄膜都是刚性固定的，光源在薄膜上扫描。结果发现，爱普生扫描仪在两种类型的胶片上的表现都一样好，在所有指标上的一致性都超过90%。(c) 2007年美国医学物理学家协会。
Intensity-modulated radiotherapy (IMRT) treatment plan verification is often done using Kodak EDR2 film and a Vidar Dosimetry PRO (TM) film digitizer. However, since many hospitals are moving towards a filmless environment, access to a film processor may not be available. Therefore, we have investigated a newly available Gafchromic((R)) EBT film for IMRT dosimetry. Planar IMRT dose distributions are delivered to both EBT and EDR2 film and scanned with the Vidar VXR-16 as well as an Epson Expression 1680 flatbed scanner. The measured dose distributions are then compared to those calculated with a Pinnacle treatment planning system. The IMRT treatments consisted of 7-9 6 MV beams for treatment of prostate, head and neck, and a few other sites. The films were analyzed using FilmQA (TM) (3cognition LLC) software. Comparisons between measured and calculated dose distributions are reported as dose difference (DID) (pixels within +/- 5%), distance to agreement (DTA) (3 mm), as well as gamma values (gamma) (dose +/- 3 %, dist. = 2 mm). Using EDR2 with the Vidar scanner is an established technique and agreement between calculated and measured dose distributions was better than 90% in all indices (DD, DTA, and gamma). However, agreement with calculations deteriorated reaching the lower 80% for EBT film scans with the Vidar scanner in logarithmic mode. The EBT Vidar scans obtained in linear mode showed an improved agreement to the upper 80% range, but artifacts were still observed across the scan. These artifacts were very distinct in all EBT scans and can be attributed to the way the film is transported through the scanner. In the Epson scanner both films are rigidly immobilized and the light source scans over the film. It was found that the Epson scanner performed equally well with both types of film giving agreement to better than 90% in all indices. (c) 2007 American Association of Physicists in Medicine.