Evaluation and Comparison of the Dose Received by the Mandible, Maxilla, and Teeth in Two Methods of Three-dimensional Conformal Radiation Therapy and Helical Tomotherapy

Background: Using three-dimensional conformal radiation treatment (3D-CRT) and helical tomotherapy (HT), this study examines and contrasts the dosage received by the mandible, maxilla, and teeth. Methods: Sixteen patients with head-and-neck cancer (H and NC) were the subject of treatment planning at the Seyyed Al-Shohada Hospital in Isfahan, Iran. This study examined target coverage quality, exposure of healthy tissue, and radiation delivery effectiveness. Results: In terms of a number of measures, including D-2%, D-50%, D-mean, V-95%, conformity index (CI), and homogeneity index (HI) for the planning target volume (PTV) and D-2%, D-98%, D-mean, V-95%, CI, and HI for the nodal PTV, HT showed considerable gains over 3D-CRT. The brainstem, D-1cc, and D-10cc received considerably lower maximum dosages in HT. Measurements of the right and left cochleas (D-mean, V55, and D-max) revealed decreases in HT, with D-mean revealing the most significant variations. The D-mean and D-max values for HT significantly decreased in constrictors as well. In terms of several HT-related indicators, the larynx, optic chiasm, optic nerves, oral cavity, mandible, thyroid, and parotid glands all showed considerable decreases. Conclusion: The findings of the comparison of the two treatment approaches revealed that the HT method was more than 50% more effective than the 3D-CRT method in sustaining organs at risk (OARs) and the target volume dose. In general, dosimetric coverage, homogeneity, conformity indices, and the absence of cold and hot patches showed that HT produced targets with greater accuracy than 3D-CRT. In addition, HT outperformed 3D-CRT in protecting important structures (OARs). HT as a result has the potential to be a more effective method of treatment for those with H and NC and involvement of regional lymph nodes.