Open AccessPreliminary study of clinical application on IMRT three‐dimensional dose verification‐based EPID system
Author(s) -
Huang Miaoyun,
Huang David,
Zhang Jianping,
Chen Yuangui,
Xu Benhua,
Chen Lixin
Publication year - 2017
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12098
Subject(s) - nuclear medicine , medicine , radiation treatment planning , radiation therapy , radiology
Abstract The three‐dimensional dose (3D) distribution of intensity‐modulated radiation therapy ( IMRT ) was verified based on electronic portal imaging devices ( EPID s), and the results were analyzed. Thirty IMRT plans of different lesions were selected for 3D EPID ‐based dose verification. The gamma passing rates of the 3D dose verification‐based EPID system (Edose, Version 3.01, Raydose, Guangdong, China) and Delta4 measurements were then compared with treatment planning system ( TPS ) calculations using global gamma criteria of 5%/3 mm, 3%/3 mm, and 2%/2 mm. Furthermore, the dose–volume histograms ( DVH s) for planning target volumes ( PTV s) as well as organs at risk ( OAR s) were analyzed using Edose. For dose verification of the 30 treatment plans, the average gamma passing rates of Edose reconstructions under the gamma criteria of 5%/3 mm, 3%/3 mm, and 2%/2 mm were (98.58 ± 0.93)%, (95.67 ± 1.97)%, and (83.13 ± 4.53)%, respectively, whereas the Delta4 measurement results were (99.14% ± 1.16)%, (95.81% ± 2.88)%, and (84.74% ± 7.00)%, respectively. The dose differences between Edose reconstructions and TPS calculations were within 3% for D 95% , D 98% , and D mean in each PTV , with the exception that the D 98% of the PTV ‐clinical target volume ( CTV ) in esophageal carcinoma cases was (3.21 ± 2.33)%. However, the larger dose deviations in OAR s (such as lens, parotid gland, optic nerve, and spinal cord) can be determined based on DVH s. The difference was particularly obvious for OAR s with small volumes; for example, the maximum dose deviation for the lens reached (−6.12 ± 5.28)%. A comparison of the results obtained with Edose and Delta4 indicated that the Edose system could be applied for 3D pretreatment dose verification of IMRT . This system could also be utilized to evaluate the gamma passing rate of each treatment plan. Furthermore, the detailed dose distributions of PTV s and OAR s could be indicated based on DVH s, providing additional reliable data for quality assurance in a clinic setting.