Abstract:

Objective The purpose of this study was to investigate the dosimetric benefits of bone marrow-sparing intensity-modulated radiotherapy （BMS-IMRT） compared with conventional intensity-modulated radiotherapy （IMRT） without dose constraint of pelvic bone marrow in the treatment of patients with cervical cancer after hysterectomy. Methods 13 patients with cervical cancer after hysterectomy were selected. BMS-IMRT and IMRT planns were designed for every patient respectively. The clinical target volume （CTV）was delineated at the doctor workstation，and CTV was uniformly expanded 1 cm to generate the planned target volume（PTV）. The organs at risk included small bowel，rectum，bladder，femoral head and bone marrow. The prescribed dose to the PTV was 50 Gy. All plans had 95% of PTV volume received the prescription. The dosimetric comparisons of target and organs at risk were performed among two plans. Results BMS-IMRT was inferior than IMRT in terms of HI，the average target dose increased by 0.36%（P<0.05）.The planned pass rate has declined，pass rate of absolute dose had significant difference ［（99.466±0.150）% vs（99.750±0.175）%，t=3.576，P=0.016］. When compared with IMRT，V₁₀，V₂₀，V₃₀ and V₄₀ of bone marrow in BMS-IMRT were reduced by 1.99％，10.30％，13.79％ and 26.46％，respectively（P<0.05）. There were no significant differences in theV45 and V₃₀ of small bowel，the V₄₀ of bladder，the V₄₀ and V₅₀ of rectum between the two plans（P>0.05）. Conclusions For patients with cervical cancer after hysterectomy，BSM-IMRT can reduce the bone marrow irradiated volume.

Key words: Uterine neoplasms, Bone marrow-sparing, Intensity modulated radiation therapy, Dosimetry