%0 Journal Article
%T Incorporating breath holding and image guidance in the adjuvant gastric cancer radiotherapy: a dosimetric study
%A Weigang Hu
%A Jinsong Ye
%A Jiazhou Wang
%A Qing Xu
%A Zhen Zhang
%J Radiation Oncology
%D 2012
%I BioMed Central
%R 10.1186/1748-717x-7-98
%X Setup errors and target motions of 22 post-operative gastric cancer patients with surgical clips were analyzed. Clips movement was recorded using the digital fluoroscopics and the probability distribution functions (pdf) of the target motions were created for both the free breathing (FB) and BH treatment. For dosimetric comparisons, two intensity-modulated radiotherapy (IMRT) treatment plans, i.e. the free breathing treatment plan (IMRTFB) and the image-guided BH treatment plan (IMRTIGBH) using the same beam parameters were performed among 6 randomly selected patients. Different margins for FB and BH plans were derived. The plan dose map was convoluted with various pdfs of the setup errors and the target motions. Target coverage and dose to organs at risk were compared and the dose-escalation probability was assessed.The mean setup errors were 1.2£żmm in the superior-inferior (SI), 0.0£żmm in the left-right (LR), and 1.4£żmm in the anterior-posterior (AP) directions. The mean target motion for the free breathing (vs. BH) was 11.1£żmm (vs. 2.2£żmm), 1.9£żmm (vs. 1.1£żmm), and 5.5£żmm (vs. 1.7£żmm) in the SI, LR, and AP direction, respectively. The target coverage was comparable for all the original plans. IMRTIGBH showed lower dose to the liver compared with IMRTFB (p£ż=£ż0.01) but no significant difference in the kidneys. Convolved IMRTIGBH showed better sparing in kidneys (p£ż<£ż0.01) and similar in liver (p£ż=£ż0.08).Combining BH technique with online image guided IMRT can minimize the organ motion and improve the setup accuracy. The dosimetric comparison showed the dose could be escalated to 54£żGy without increasing the critical organs toxicities, although further clinical data is needed.
%K Gastric cancer
%K Intensity-modulated radiotherapy
%K Breath holding
%K Image-guided radiotherapy
%K Dose convolution
%U http://www.ro-journal.com/content/7/1/98/abstract