Sri Krishna Gangarapu - Department of Radiotherapy, MNJ Institute of Oncology & Regional Cancer Centre,Hyderabad-۵۰۰۰۰۴,Telangana,INDIA
Srinivas Vuppu - Department of Radiotherapy, MNJ Institute of Oncology & Regional Cancer Centre, Hyderabad-۵۰۰۰۰۴, Telangana,INDIA

Introduction: The present study aimed to compare plans with Bone Marrow sparing (BM-IMRT) and without Bone Marrow Sparing (N-IMRT). Material and Methods: Fifteen cases of cervical cancer cases were selected for retrospective study. All the cases were previously treated with normal IMRT. For this study, plans with BM-IMRT were created again for all patients following RTOG guidelines. The prescribed dose of ۵۰Gy in ۲۵ fractions was given. The plan having coverage of ۹۵% of PTV receiving ۹۵% of the prescribed dose was accepted. The plans were compared based on PTV coverage (dose to ۲%, ۹۸% of target); constraints of OARs (Organs at Risk) were the volume of ۴۰% < ۴۰Gy for normal bladder and rectum (volume receiving dose ۵Gy) V۵<۹۵%, V۱۰<۸۰%, V۲۰<۶۰%, V۳۰<۵۰% and V۴۰<۳۵% respectively for Bone marrow and lowest possible doses to bowel were given for planning criteria. Apart from this, HI, CI and R۵۰% were also calculated concerning PTV coverage to analyze plan quality. Results: There was a statistical difference in P-values of D۲, D۹۸, TV۹۵, HI, R۵۰% but the actual difference is less than ۲%. In the case of OARs, there were also significant differences in statistical as well longitudinal in values of V۱۰, V۲۰, V۳۰ and V۴۰ of Bone Marrow (P<۰.۰۱) and there was only statistical differences (p<۰.۰۵) at V۵۰ of bladder and rectum. Conclusion: Without scarifying dose coverage for planning target volume, bone marrow can be spared while treating cervical cancer patients using IMRT technique with bone marrow as an extra constraint.

Bone marrow sparing, CI, HI, Dose Spillage Index