[Abdominal irradiation in seminomas: improvement in its planning with MRT].

BACKGROUND

Standard therapy for early stages of seminomas is the irradiation of the para-aortal and paracaval lymphatic vessels.

PATIENTS AND METHOD

Prior to radiotherapy coronal T1-weighted MRI of the abdomen was performed including imaging of target volume and critical organs. The position and course of the large abdominal vessels are projected on simulator radiographs of the abdomen. The target volume is enclosed by blocks, which are individual formed with a 2 cm margin along the vessels.

RESULTS

An irregular course of the vessels in 34% of the patients resulted in modifications of the radiation field compared with standard fields. Thus more than 10% of the volume of the left kidney could be taken out of field in 25% of the patients. Simultaneously fields were enlarged on contralateral side to make sure that the paracaval lymphatic drainage was enclosed.

CONCLUSIONS

MRI-assisted planning of radiotherapy allows a more individualized treatment by visualization of the big abdominal vessels guiding the para-aortal lymphatics. The target volume is surely enclosed, healthy organs are optimal spared.