A multicentric study involving eight Italian brachytherapy centers was performed to analyse to what extent the variations in the reconstructed seed distribution can affect the dosimetric parameters commonly used in post plan evaluations of permanent prostate brachytherapy. The geometrical seeds distributions were reconstructed by eight reviewers on CT and MR images of six implanted patients. Independently on the imaging modality, the geometric reconstruction of the seeds distribution showed little effect on quality dosimetric parameters D9D and V100 of the prostate implant. On the contrary a strong effect upon organs at risk (OARS) related parameters was found. The spread of the D1 and V150 values for the urethra calls into question the significance and the specificity of these parameters. Our preliminary results show the difficulty of collecting dosimetric data that could be correlated with biochemical relapse-free survival (RFS) or prostate specific antigen (PSA) and, particularly, with side effects. Nevertheless, in our opinion, prostate and OAR contouring remains the largest source of uncertainty in post plan evaluation.
|Number of pages||5|
|Publication status||Published - Jul 2004|
- Dosimetric parameters
- Permanent prostate brachytherapy
- Post-plan dosimetry
ASJC Scopus subject areas
- Physics and Astronomy(all)