Dosimetric outcomes of the breast field-in-field (FIF) radiotherapy technique in patients with mastectomy and lumpectomy surgeries

Background: field-in-field (fif) technique for treatment of breast cancer hasbecome a widely performed method over the recent years. however, there was nostudy in the applica on of fif technique in pa ents with breast cancer undergoingmastectomy and lumpectomy. this study is an a#empt to compare dosimetricoutcomes a$er applying the fif technique in these pa ents. materials andmethods: twenty-four pa ents with right and le$ breast cancer par cipatedin this study. the fif planning technique was carried out for pa entsundergoing mastectomy and lumpectomy using the tigrt treatment planningsystem (tps). for the comparison purpose, we used two main indices, i.e.dose homogeneity index (hi) and conformity index (ci), the number ofsubfields, as well as mean, maximum, and minimum doses, doses received by2% (d2) and 98% (d98) of the target volume, volumes received greater than107% (v>107%) and less than 95% (v<95%) of the prescribed dose, doses toorgans at risk (oars), and total monitor units (mus). results: the resultsindicated that ci and hi are be#er in pa ents with right and le$ breastlumpectomy surgery (p<0.038 and p<0.047) rela ve to mastectomy pa ents(p<0.037 and p<0.029), respec vely. other parameters men oned inmaterials and methods did not show any significant difference between thetwo groups of pa ents (p>0.05). conclusion: the use of alterna ve subfieldsresulted in be#er dose distribu on in target volume with the increase in breastvolume. moreover, to disappear the hot spot areas in isodose curves, it is essen alto elevate the number of subfields.