Program Information
Dosimetric Comparison of Cyberknife Versus Linac Based VMAT Stereotactic Treatment Planning for Localised Prostate Cancer
V Senniandavar1*, S Vikraman1 , K KP1 , T Rajesh1 , R Sambasivaselli1 , M Ramu1 , S Maragathaveni1 , N Dhivya1 , K Tejinder1 , (1) Medanta the Medicity Hospital, Gurgaon, Haryana
Presentations
SU-E-T-305 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:The purpose of this study was to compare dosimetric indices of Cyberknife versus Linac for localised prostate cancer
Methods:In this study, twenty patients were taken from Cyberknife Multiplan TPS v 4.6.0. All these patients underwent hypo fractionated boost treatment for localised prostate cancer in Cyberknife with the prescription dose of 18Gy in 3 fractions. For each patient VMAT stereotactic plans were generated in Monaco TPS v 5.0 using Elekta beam modulator MLC machine for 6MV photon beam. The plans quality were evaluated by comparing dosimetry indices such that D95, D90, D5 for target volume and V100, V80, V50, V30 for critical organs. The p values were calculated for target and OAR to ascertain the significant differences.
Results:For each case, D95 of target coverage was achieved with 100% prescription dose with p value of 0.9998. The p value for D90, D5 and V100 for linac and Cyberknife plans was 0.9938, 0.9918 and 0.9838 respectively. For rectum, rectum-PTV and bladder doses were significantly less in Cyberknife compared to linac plans. For rectum, rectum-PTV and bladder at V100 the p value is 0.2402, 0.002, and 0.1615 respectively. Other indices V80, V50 and V30 were comparable in both plans.
Conclusion:This study demonstrated that both linac and Cyberknife plans were shown adequate target coverage, while in Cyberknife the treatment time is longer and more MUs to be delivered. However, better conformity, lesser doses to the critical organs and dose gradient outside target for localised prostate treatment were achieved in Cyberknife plans due to multiple non coplanar beam arrangements.
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