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.2020.2381
Summary
OBJECTIVEWe 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.