EP-1247: Simulating intra-fraction prostate motion using random walk and conditional Gaussian based Gibbs sampling models
Year: 2013
Type: conference-abstract
Abstract: 2nd ESTRO Forum 2013 S467 the exhalation phase.Before the treatment delivery, the RPM block was put on patient's abdominal surface and the gating signal was generated by the RPM system.Then, the patient's position was set based on cone beam computed tomography (CBCT) compare with ITV.During the treatment, kv images were acquired at each exhalation phase of the breathing cycle and the positions of the fiducial markers were compared with their expected positions.We reported here for the five first fractions the differences between expected and real fiducial position, treatment planning parameters such as the prescription, conformity index CI PTV = (V ITV95% (cc) / V PTV (cc) ) * (V ITV95% (cc) / V iso95% (cc) ), homogeneity index HI PTV = (D 2% -D 98% ) / D median and the number of Monitor Unit (UM) per Gray.The treatment delivery parameters such as kv images acquired per fraction, the fraction's time and the room occupation's time were also mentioned.Results: For the eight PTV patients, the average (±SD) conformity index was 0,93 ± 0,02 and homogeneity index was 0,09 ± 0,02.Average MU/Gy was 147 ± 25.Maximum deviation in the Superior-Inferior (SI) direction during the intrafraction ranged from 4 mm to 6 mm. Conclusions:The average gating errors measured were small compare with the 5 mm margin added to the ITV to create the PTV.However, regarding to maximal error, this additional margin is suitable to treat the tumor with no misses due to the liver motion.
Source: Radiotherapy and Oncology
Authors: T. Pommer, J.H. Oh, P. Munck af Rosenschöld, J.O. Deasy
Institution: Centre Oscar Lambret
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,770
OpenAlex ID: W2892264597