Abstract：Objective To study accuracy and stability of bladder mold volume using fan beam CT (FBCT) and kilovoltage cone-beam CT (CBCT). Methods The water bladder molds in 2 categories:hard and soft water wall molds (1 group and 3groups), scanned by FBCT and CBCT. FBCT was scanned by 2 rows of Hispeed dual and 64 rows of Lightspeed VCT spiral scan, then it was divided into two groups according to the pitch/speed of bed. CBCT was scanned by pelvis, pelvis spotlight and high quality head scan. Every scan repeated 5 times, then compared reconstruction volume with the real volume, analyzing stability and repetition by treatment planning system and the results of two phantoms by using independent sample t test. Results The deviation which compared the hard wall phantom with the real value was FBCT:－(1.5-0.2)%, CBCT:－(5.1-2.9)%.The deviation of soft wall molds, FBCT:－(4.2-0.1)%, CBCT:－(4.0-0.3)%.Reconstruction volume of FBCT decreases with the increase of motion speed and pitch of bed,the volume of Hispeed was greater than the Lightspeed (hard wall molds, P=0.010 and soft wall molds, P=0.004).Among CBCT modes, the pelvis one had the smallest reconstruction volume (hard wall molds:CBCTH vs. CBCTP,P=0.020, CBCTP vs. CBCTPS P=0.013 and soft wall molds:CBCTH vs. CBCTP,P=0.006, CBCTP vs. CBCTPS P=0.008.). Conclusions Reconstruction volume of FBCT and CBCT have no statistical difference, and both of them have a good repeatability. Slow scan mode is recommended when using FBCT for active organ (respiration, filling and so on). Pelvis spotlight and high quality head protocols are recommended when using CBCT scanning.
Hu Jian,Xu Liming,Li Changhu et al. Analysis of accuracy of bladder volume by simulating water mold based on Computed Tomography and kilovoltage cone-beam computed tomography images[J]. Chinese Journal of Radiation Oncology, 2014, 23(5): 426-428.
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