Comparison of V10 and V20 of bone marrow in carcinoma cervix
patients receiving radiation with Bone Marrow Sparing (BMS)–IMRT, IMRT , 3DCRT, and 4
field box technique.
OBJECTIVE:
To assess the feasibility of modelling Bone Marrow Sparing IMRT without compromising the
dose to the planning target volume and without increasing the dose to other organs at risk.
METHODS:CT Data set from 16 women with Carcinoma cervix treated in our institution from
July 2013 to January 2014 using 3D CRT or IMRT were selected for the study. For all the 16
patients ,4 plans ;four field box,3DCRT, IMRT and Bone Marrow Sparing IMRT were
modeled.Bone marrow was contoured using free hand technique in each CT cut including entire
L5 vertebral body, sacrum, coccyx, ileum, ischium, pubis and femoral head extending down till
the level of ischial tuberosity. Constraints to the organs at risk and the target volume were
prescribed as per the standard RTOG guidelines.Bone Marrow constrain was V10< 95% and V
20< 76%.Dose volume histogram,isodose curves, dose colour wash and presence of hot spot
were used for plan evaluation. Chi-square test was used for statistical analysis.
RESULTS
Out of the 16 plans with BMS IMRT, 15 plans achieved the desired goals while respecting the
bone marrow constrains. This gave a 93.8% chance of achieving this constrain with a p value of
.001.The The mean V10 and V20 to bone marrowin our study was 89.58% and 69.99%. In case
of femoral head, it was observed that the constrain was attained for 12/16 patients with 4 FIELD
BOX, 12/16 patients for 3DCRT, 16/16 patients with IMRT and 16/16 patients with BMS –
IMRT.The bowel bag constrain could be achieved for 13/16 patients with 4 FIELD BOX plan,
12/16 patients with 3DCRT plan, 16/16 patients with IMRT plan an 16/16 patients with BMS –
IMRT plan .Bladder and rectum constrains could not be achieved in any of the plans.
Bone Marrow Sparing IMRT is a feasible option for the management of locally advanced
carcinoma cervix as it helps in reducing the dose received by the bone marrow without
compromising the planning target volume coverage and without increasing the dose to other
normal organs at risk
