entrance surface dose measurement at thyroid and parotid gland regions in cone-beam computed tomography and panoramic radiography

Purpose: ionizing radiation-absorbed doses is a crucial concern in cone-beam computed tomography (cbct) and panoramic radiography. this study aimed to evaluate and compare the entrance skin doses (esd) of thyroid and parotid gland regions in cbct and panoramic radiography in yazd province, iran.materials and methods: in this cross-sectional study, 332 patients were included, who were then divided into two age groups (adult and pediatric) and underwent dental cbct and panoramic radiography. twelve thermoluminescence dosimeters (tld- gr200) were used for each patient to measure the esd of thyroid and parotid glands. the differences between the esd values in cbct and panoramic examinations as well as between the adults and children groups were evaluated by one-way anova and man-whitney tests.results: the mean and standard deviation (sd) values of esd in panoramic imaging were equal to 61 ± 4 and 290 ± 12 μgy for the thyroid and parotid glands of the adult groups, respectively. notably, these values for cbct were significantly higher (p<0.01), as 377 ± 139 and 1554 ± 177 μgy, respectively. moreover, the mean esd values in the panoramic examination were 41 ± 3 and 190 ± 16 μgy for thyroid and parotid glands for the children group, while they were 350 ± 120 and 990 ± 107 μgy in cbct (p<0.01), respectively. the esd values in the parotid gland were approximately 3.4 (2.8-4.1) and 4.7 (4.6-4.8) times greater than those for cbct and panoramic examinations, respectively.conclusion: although cbct provides supplementary diagnostic advantages, the thyroid and parotid glands’ doses are higher than panoramic radiography. therefore, the risks and benefits of each method should be considered before their prescription.