Radiation exposure and distribution measurements for three panoramic x-ray machines.

1. Exposures to internal sites in the phantom varied as follows: Panorex, 0.3 mr to 2.4 r; Orthopantomography, 0.4 mr to 0.8 r; Panelipse, 0.2 mr to 1.4 r. 2. With the phantom exposed for a normal-density radiograph at 65 KVP, the average radiation exposure at the sites measured were for the Panorex, Orthopantomograph, and Panelipse respectively: 8, 13, and 4 mr at the pituitary gland; 22, 62, and 8 mr at the superior area of the parotid gland; 13, 8, and 5 mr at the thyroid gland; 343, 425, and 365 mr at the submaxillary gland; and 50, 154, and 272 mr at the base of the tongue. 3. External exposures to the phantom and patients were found to be in good agreement at the low KVP. At the high KVP (using patients who were larger than the phantom), exposures at lateral and posterior sites showed relatively good agreement between phantom and patients, while exposures at anterior sites were less in patients. 4. The average stray radiation measurement at 1 meter from the phantom during pantomography with the three machines was 0.125 mr per exposure cycle. Individual averages were: Panorex, 0.10 mr; Orthopantomograph, 0.13 mr; and Panelipse, 0.15 mr.