túi tinh hoặc sự tham gia của hạch bạch huyết, họ cũng có tầm quan trọng nổi bật cho định nghĩa mục tiêu trong quá trình lập kế hoạch điều trị xạ trị. Câu hỏi có hay không để irradiate các hạch bạch huyết vùng chậu | 11 Radiation Therapy in Prostate Cancer 183 seminal vesicle or lymph node involvement they are also of outstanding importance for target definition during radiotherapy treatment planning. The question of whether or not to irradiate pelvic lymph nodes may be further clarified by recent studies on new imaging modalities which provide evidence that pelvic nodal radiation portals should be based on vascular rather than on bony anatomy landmarks because of the localization of nodal metastases in prostate cancer along the major pelvic vasculature. These results were obtained by lymphotropic nanoparticle enhanced MRI LNMRI which has proved to be useful in the detection of minimal disease in normal-sized nodes at high sensitivity and specificity Brassell et al. 2005 Shih et al. 2005 Will et al. 2006 . The efficient implementation of conformal techniques into prostate cancer treatment has been promoted by systematic and accurate evaluation of internal organ motion proper patient preparation and positioning and treatment verification procedures. Currently there is no patient preparation procedure that can be regarded as standard. Although recent publications have clarified some obscurities controversies remain about many issues such as bladder filling feet fixation etc. Patient immobilization devices significantly reduce errors in patient positioning especially in the prone position. The question of patient positioning has been an issue of controversy for some years. Currently there is only one prospective randomized trial comparing supine and prone position. Bayley et al. found a significant advantage in the supine treatment position with respect to prostate movement number of set-up corrections patient comfort and radiation therapist convenience as well as for all dose levels for small bowel rectal wall and bladder wall doses Bayley et al. 2004 . Another issue in clinical quality assurance is treatment verification. In recent years verification procedures have been .
