[INTRODUCTION - Modern radical radiotherapy can be an effective alternative of radical prostatectomy in low risk patients with prostate tumor. Our objective was to demonstrate the feasibility of transperineal MR-guided prostate interventions in an open MR unit and to present our early clinical experiences on canines. METHODS AND MATERIALS - The procedures were performed on 5 canines in an open-configuration 0.35T MR scanner. For interventions an MR compatible custom-made device was used. The canines were placed in the right lateral decubitus position. Template reconstruction, trajectory planning, target and OAR delineation were based on T2 FSE images. For image guidance and target confirmation, fast spoiled gradient-echo (FSPGR) sequence was used. MR compatible coaxial needles were inserted through the perineum to the base of the prostate. After satisfactory position was confirmed, brachytherapy catheters were placed through the coaxial needles, which were then removed. RESULTS - Mean and standard deviation of the needle displacements was 2.2 mm±1.2 mm, with a median of 2 mm. 96% of the errors were less than 4.0 mm. Implantation induced prostate motion was measured with a mean of 10.3 and 2.3 mm in cranio-caudal and transverse directions. Significant movement was only observed during the first 4 needle insertions. The average time needed for each step was: anesthesia 15 minutes, setup and positioning 15 minutes, initial imaging 15 minutes, template registration and projection 15 minutes, contouring, trajectory planning, insertion of 10 needles 60 minutes. CONCLUSION - Based on our canine model experiences our method seems to be a promising approach for performing feasible, accurate, reliable and high-quality prostate MR guidance within a reasonable time span. We plan to introduce MR-guided biopsy and brachytherapy in human patients in the near future.]

[INTRODUCTION - As the result of mammographic screening of breast cancer, the incidence of surgically removable, non-palpable breast lesions is increasing. The study is aimed to demonstrate the use of radioisotope and gamma-probe for identifying the sentinel lymph node and the intraoperative radioguided localization of occult breast lesions. PATIENTS AND METHODS - 26 patients with nonpalpable breast lesions underwent radioisotope guided sentinel lymh node localization for staging purposes. In eight patients non-palpable breast lesions were localized with use of radioisotope method intraoperatively. RESULTS - All breast lesions were successfully localized pre- and intraoperatively. The combined radioisotope and blue-dye staining method increased the sensitivity of the procedure for identifying sentinel lypmh node. In case of 14 patients with negative sentinel node, the surgical dissection of axillary lymph nodes was avoided. CONCLUSION - Radioguided localization is a simple, quick and accurate technique for localization of nonpalpable breast lesions and sentinel lymph node, which is utilized for the up-to-date and correct oncological management of the breast cancer patients.]