TURKISH JOURNAL OF ONCOLOGY 2017 , Vol 1 , Num 3
Dosimetric Evaluation of Intensity Modulated Radiotherapy and Three-Dimensional Conformal Radiotherapy Treatment Plans for Prostate Cancer
Samuel ADENEYE1,Michael AKPOCHAFOR1,Muhammad HABEEBU1,Akintayo OMOJOLA3,Adedayo JOSEPH2,John AWHARİADO1,Abayomi DUROSINNMI-ETTI2,Moses AWEDA1
1Department of Radiation Biology, Radiotherapy and Radiodiagnosis, College of Medicine, University of Lagos, Lagos-Nijerya
2Department of Radiotherapy, Nigerian Sovereign Investment Authority?Lagos University Teaching Hospital, Lagos-Nijerya
3Department of Radiology, Federal Medical Centre Asaba, Medical Physics Unit, Asaba-Nijerya
DOI : 10.5505/tjo.2020.2437 OBJECTIVE
We evaluated the homogeneity index and conformity index using intensity modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) treatment plans in prostate cancer.

METHODS
Twenty treatment plans for ten patients were created using 3D-CRT of four-fields with gantry angles of 0?, 90?, 180?, and 270?; and IMRT of five-fields with gantry angles of 0?, 72?, 144?, 216?, and 288? on an Eclipse Treatment Planning System (version 15.6). The volume of reference isodose, target volume, maximum isodose in the target, reference isodose, dose at 95% of planning target volume (PTV), dose at 2%, 5%, and 98% of PTV, and prescribed dose were collected from the dose volume histogram of each plan. The conformity index and homogeneity index (HI) were then calculated. The doses of the organs at risk were also collected and evaluated.

RESULTS
The HI of the twenty patients who underwent the treatment plan with 3D-CRT was 1.088±0.03, which shows good homogeneity, but less homogeneity when compared with plans done with IMRT (1.072±0.02).

CONCLUSION
The use of IMRT treatment plan for prostate cancer proved to be superior over 3D-CRT in terms of conformity and homogeneity, as well as sparring dose to organ at risk. Keywords : Conformity index; homogeneity index; intensity modulated radiotherapy; prostate cancer; 3D-conformal radiotherapy