ROLE OF COMPUTER PLANNING AND CT GUIDED PLANNING IN MINIMIZING RADIOTHERAPY INDUCED COMPLICATIONS IN PATIENTS TREATED WITH POSTOPERATIVE RADIOTHERAPY FOR CARCINOMA OF THE BREAST

Abstract

I. The recalculated manual plans. J

The . mean dose to the target from left tangential field was

61±12.4%. The mean volume of the target that received 95-107% (ICRU

50 recommendation) of the prescribed dose was 26±14% only. The cumulative mean dose to the heart from both direct left internal mammary field and left tangential field was 38%. The mean volume of the heart that received 24Gy or more was 33±15% and the mean volume of the heart that received 40Gy or more was 2.5±3%. The mean length of the GPD in the recalculated manual plan for breast cancer patients was 2.5±9 em.

II. The use of 1 CT cut plan (CAX) versus 3-CT cuts plans.

The mean percentage dose delivered to thetarget volume using single CT cut was 101±4 compared to 96±4 for the 3 CT cuts plan and the difference was statistically significant (P<O.OOl). The mean volume of the target fulfilling the ICRU 50 recommendations for dose criteria was 77±19% in the I cut plan compared to 52±11% in the 3 CT cuts recalculated (Beam parameters were not changed) plan .The difference was statistically significant (P <0.001). So performing a single slice calculation •plan is not accurately predicting the dose variation across the whole treatment volume particularly near the upper and lower borders. Therefore the 3CT slices plan was a more accurate indication of the dose distribution across the planning target volume (PTV).