COMBINED IRRADIATION OF PELVIS AND INGUINALNODAL REGIONS USING MODIFIED SEGMENTAL BOOST TECHNIQUE: A PROSPECTIVE STUDY.

Abstract

AIM: To describe a novel Modied Segmental Boost Technique (MSBT) for combined irradiation of pelvis and inguinal nodes and to compare the dosimetry of the new method with that of other traditional methods of radiation treatment and IMRT. Total 30 patients who required combined irradiation of pelvis and inguinal regi METHODS AND MATERIALS: ons are included in our study to illustrate details and advantages of MSBT. Conventional photons with enface electrons design was created rst with two opposing parallel elds and four eld box. MSBT plans are generated and patient is treated with this technique to TD 45-50Gy for 5-6 weeks duration. A step-and-shoot inverse IMRT planning was subsequently generated. For dosimetric comparison, these treatment techniques were evaluated by dose-volume histogram (DVH) of PTV and OARs. Dose proles at different depths from each treatment planning were generated for comparison. Comparing the modied segmental boost technique with conventional two oppos RESULTS: ing and four eld box technique, we have found out that the target coverage, dose homogeneity index (DHI) and femoral head sparing is superior in modied segmental boost technique compared to other conventional approaches. And also the patients had better clinical response of both primary and the nodes with minimal skin morbidity when compared with conventionally treated patients data. DHI and target coverage of MSBT was comparable with that of IMRT. CONCLUSION: To cover pelvis and inguinal/femoral nodes, MSBT is technically simple to simulate, plan, and execute. Dosimetric study has demonstrated that it achieves comparable PTV coverage compared with other approaches while at the same time signicantly sparing the surrounding OAR .It also has dose homogeneity comparable with IMRT and can be a nearer alternative for IMRT, in centers which are not having the facility and where the patient load is higher.