THE ROLE OF LYMPHANGIOGRAPHY IN DESIGNING FIELDS FOR ELECTIVE PELVIC NODE IRRADIATION IN HODGKINS-DISEASE

Purpose: We attempted to design a standard pelvic nodal treatment fiel d such that all lymph nodes usually visualized on lymphangiogram would be irradiated with optimal midline blocking of normal tissues. Method s and Materials: Two standard fields for treatment of pelvic lymph nod es were designed, based on bony landmarks. The standard fields were ap plied to the anterior-posterior view of 35 pretherapy lymphangiograms, and the fields were then assessed for inclusion of visible lymph node s. Measurements were done on the lymphangiograms to assess the amount of additional midline blocking that could be added. Results: All visua lized nodes were included in 30 patients (86%) using Standard Field I and in 33 patients (94%) using Standard Field II, but visualized nodes plus a 1.5-cm minimum margin were included in only two patients (6%) with Field I and 24 patients (69%) with Field II. The most frequent si tes of close margins were the lateral and medial borders adjacent to t he external iliac nodes. Based on the lymphangiograms, a mean of 1.6 c m in male patients and 3.1 cm in female patients could be added to the width of the midline blocks. Conclusion: Lymphangiography is useful i n designing fields for pelvic node irradiation, both to improve covera ge of nodes with a 1.5 cm margin and to increase the amount of central shielding of normal tissues.