Document Type : Original Paper
Department of Physics, College of Natural and Applied Sciences, University of Dar es Salaam, Tanzania
Department of Radiotherapy, Ocean Road Cancer Institute, Dar es Salaam, Tanzania
Tanzania Atomic Energy Commission
Department of Physics, University of Dar es Salaam, Dar es Salaam, Tanzania
Introduction: Dose planning is one of the important steps for the effective implementation of radiotherapy. As recommended, 95% to 107% of the prescribed dose should cover the target volume. Thus, radiotherapy cannot improve patient outcomes unless the desired dose delivery accuracy is achieved. The study was performed to evaluate field-in-field (FIF) technique (Forward intensity-modulated radiotherapy) compared with 3D-conformal radiotherapy enhanced dynamic wedge (EDW) technique. Materials and Methods: Two plans with opposed tangential fields; FIF and EDW for each breast cancer patient were created. Results: The two techniques were comparable as far as the DMax, D2%, and D5% were concerned. However, the FIF plan was slightly superior to EDW as far as D95% and D98% were concerned. The V95% was slightly higher in favor of FIF technique. The superiority of the FIF technique was further demonstrated by the lower mean dose (Dmean) and the volumes receiving 10 Gy (V10Gy) and 20 Gy (V20Gy) of the prescribed dose for the heart. The Dmean, V5Gy, V10Gy, and V20Gy for ipsilateral and contralateral lungs were comparable between the two techniques. However, the FIF technique demonstrated higher Dmean to the contralateral breast than EDW technique. Conclusion: These results along with experiences elsewhere show the dosimetric benefits of the FIF technique for the optimal dose that should cover the target volume. However, the higher Dmean to the contralateral breast was a substantial shortcoming for the FIF technique. It can be recommended that the two planning techniques can be combined and used together to cover their drawbacks.