Definition of the pelvic structure in computerized tomograpy and magnetic resonanse imaging by using image fusion in radiotherapy planning for prostate cancer

Definition of the Pelvic Structure in Computerized Tomograpy and MagneticResonanse Imaging by Using Image Fusion in Radiotherapy Planning for ProstateCancerProstate cancer is the sixth common malignancy in Turkey. The maintreatment choices for men with clinically localized prostate cancer are radicalprostatectomy, external beam radiotherapy. Radiotherapy and prostatectomy arecuratively treatments and have high local control ratio.High-precision three dimensional conformal radiation therapy (3D-RT)using sophisticated computer-aided treatment planning, along with surgery, hasbeen accepted as standard therapy for localized prostate cancer. High doseconformal radiotherapy for prostate cancer increases local control. The success ofdose escalation depends on correct staging and target volume identification.Prostate is surrounded by several soft-tissue. Magnetic resonance imaging(MRI) has better soft-tissue resolution, and shows the interfaces more clearly.Fifteen consecutive patients with clinically localized prostate cancer wereprospectively evaluated with CT-MR fusion images. Our study was to assess theadvantage of CT?MRI image fusion and differenses for volume delination.Each patient underwent CT in the treatment position. MR imaging wasalso performed in the treatment position after to the CT. Both imagesautomatically matched in three dimensions. One radiation oncologist contouredthe prostate, SV, rectum, PB of all the patients referring to all the CT and MRimages. They checked by experienced radiologist.The mean delineated volumes of the prostate SV, rectum, PB analyzed.We found statistically significant difference between SV values. We showed thatMRI yields more contrast than CT when differentiating the prostate (apex, basis),rectum, PB. Prostate-Rectum and apex- PB distance identified clearly by MRI.Finally; MRI compere with CT appears to provide improved definition ofpelcic treatment volumes for prostate radiotherapy.Key words: RT, CT, MRI.