Program Information
Influence of Filtered and Flatting Filter Free Photon Beam of 10 Megavolts Energy On Rapid Arc Radiotherapy Planning for Cervix Carcinoma
Y Girigesh*, L Kumar , K Raman , M MISHRA , Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, Delhi
Presentations
SU-E-T-493 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:
Aim of this study is to determine the dosimetric influence of Filtered and Flatting Filter Free Photon Beam of 10 MV energy on RA planning for Ca. Cervix.
Methods:
CT data sets of eleven patients reported with carcinoma cervix were used for RA planning for 10MV_FFB and 10MV_FFFB. RA plans were generated using two full arcs.
All RA plans were generated to deliver a dose of 50.4Gy in 28 fractions for PTV and ALARA for OAR's. All plans were analysed for PTV Coverage, conformity Index, homogeneity index, dose to OAR’s, integral dose to normal tissue and total monitor units were studied.
Results:
DVH was used to evaluate RA plans for both 10MV_FFB and 10MV_FFFB photon beam. Planning results show a comparable PTV coverage for both energies. Results shows volume of PTV receiving prescription dose were 95.10+ 0.09% and 95.09 +0.11%, and volume of PTV receiving a dose of 107% is 0.45+0.96% and 5.25+8.9% , homogeneity index (HI) were 1.051+0.007 and 1.066+0.008, Conformity Index(CI) were 1.003+0.019 and 1.012+0.013, Mean Integral dose were 2.65+0.34 and 2.60+0.33(*10-5Gy.cm3) for 10MV_FFB and 10MV_FFFB respectively.
10MV_FB shows statistically significant (p<0.05) improvement in mean doses to bladder, rectum, bowel and mean total number of MU’s and also shows remarkable decrease in mean total no. of MU’s by 43.7% in comparison to 10MV_FFFB. There is statistically significant (p<0.05) difference found in CI and HI for 10MV_FB in comparison to 10MV_FFF beam. 10MV_FFFB shows statistically significant (p<0.05) for mean NTID and delivers 1.65 % less NTID in comparison to 10 MV_FB.
Conclusion:
10MV_FB is superior to 10MV_FFFB for rapid arc planning in case of Cervix carcinomas, it offers better target coverage and OAR’s sparing, comparable mean Integral dose to normal tissues and 10 MV_FB also produced highly conformal and homogeneous dose distribution in comparison to 10MV_FFFB.
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