CLINICAL DOSIMETRY RELATIONSHIP BETWEEN LACRIMAL GLAND DOSE AND DRY EYES SYNDROME AFTER IRRADIATING SINONASAL, MAXILLARY, NASOPHARYNGEAL TUMORS IN VARIOUS TECHNIQUES

Aim: To assess the clinical dosimetry relationship between lacrimal gland dose and dry eye syndrome after irradiating sinonasal, maxillary, and nasopharyngeal tumors in various techniques. Methods: This study is a retrospective study of the electronic medical data from 47 patients with sinonasal and nasopharyngeal tumors conducted in the Department of Radiation Oncology at Madras Medical College in Chennai, India, between January 2021 and July 2023. Results: Out of 47 study patients 55% of right eyes and 59% of left eyes received <10 Gy, ≥30 Gy in 21.3% of left and 19.1% of right eyes. V30 values were zero in 74.5% of both right and left eyes, and more than 70% of eyes had no volume exposed above 20 Gy (V20 = 0). The mean dose to the left eye in patients with toxicity was 52.0 Gy, compared to just 6.7 Gy in those without (p < 0.001). Toxicity is strongly associated with Dmean > 26 Gy and Dmax ≥ 40 Gy, with p-values < 0.001. For both eyes, toxicity signicantly increased when V10 exceeded 50% or V20 exceeded 25% (p < 0.01 in all cases). Conclusions: The study's ndings highlight the crucial link between radiation dose-volume parameters and ocular toxicity, including dry eye syndrome and Dmean, Dmax, and volumetric exposures (V10, V20, V30). The efcacy of image-guided techniques such as IMRT and VMAT in lowering complications and maintaining quality of life. Both practical dosimetric criteria and clinical validation for lacrimal gland protection will contribute signicantly to the optimization of radiation therapy and the potential for a safe and effective treatment plan.