ABSTRACT
Introduction: Since 1980s, computerization has made improvements in radiation therapy delivery from conventional two-dimensional to three-dimensional conformal radiotherapy (2DCRT to 3DCRT) to intensity-modulated radiotherapy (IMRT) and its newer versions. This small study is aimed to compare the existing techniques for planning target volume (PTV) and organ at risk (OAR) dose distribution parameters in postoperative buccal mucosa cases. Materials and Methods: Ten post operative cases of early stage carcinoma buccal mucosa in whom only post operative bed irradiation was indicated was enrolled and was planned with conventional, 3DCRT and IMRT techniques to get 95% PTV coverage and dose received by organs at risk were recorded and evaluated. Results: Mean and standard deviation values for PTV 95% for IMRT, 3DCRT, and conventional plans were 96.4 ± 1.8, 95.1 ± 1.9, and 91 ± 2.7, respectively. Dose received by OARs was high in conventional technique when compared to the other two. Maximum dose received by 1 cc of brain (46.2 ± 7.9 and 60.8 ± 3.8) (priority was given for PTV coverage) and mean dose received by the same eye (13.6 ± 1.4 and 22 ± 2.4) were less in IMRT when compared to 3DCRT. However, maximum dose received by 1 cc of brainstem (29.7 ± 7.6 and 14.1 ± 9.5), optic chiasma (29.2 ± 4.2 and 12 ± 2.1), spinal cord (31.8 ± 3 and 20.9 ± 4.2), and the same-side optic nerve (22 ± 6.9 and 11.7 ± 9.4) and mean dose received by opposite-side parotid (8.7 ± 1.1 and 1.7 ± 0.4) and submandibular gland (18.6 ± 1.7 and 3.2 ± 0.9) were more with IMRT when compared to 3DCRT. Conclusion: In postoperative cases of early-stage carcinoma buccal mucosa, it is good enough to treat with 3DCRT technique. Here, the target area will be well lateralized, and 3DCRT technique can give good target coverage and less dose to OARs, especially the only remaining major salivary glands.