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Abstract
Radiotherapy after conservation surgery has been proven to decrease local relapse and death from breast cancer, and is now firmly established in the management of early breast carcinoma. Also it has an important role after mastectomy (removal of entire breast). Currently, the challenge is to minimize the morbidity caused by this treatment without losing its efficacy.
So the main purpose of this work was to compare and evaluate different irradiation breast techniques. We studied the two most recent techniques (intensity modulated radiation technique or IMRT) and conformal tangential irradiation technique or CTI, on about 15 patient and compared them with the standard tangential irradiation technique (STI). We introduced a new breast irradiation technique using asymmetric fields to generate intensity modulated beams. We compared that new technique with the other techniques.
Treatment planning was performed and analyzed for each patient using the precise Plan planning system. The critical organs of interest in this work were lung, heart and the right breast. Plans were evaluated using dose-volume histograms (DVHs) for planning target volume (PTV), lung and heart. We also applied the maximum heart distance (MHD) and the conformation number of the PTV as an evaluation tools.
In all techniques, the PTV minimum dose was 95% of the prescribed dose. The new asymmetric fields’ technique gave results very similar to that of the IMRT results. There was a valuable reduction in the maximum dose of the PTV and the hot spots in IMRT techniques whether it is performed automatically or with asymmetric fields. The average maximum PTV dose was the highest in STI technique and the lowest in IMRT and the asymmetric fields’ technique.