Radiation dosimetry in radiology of the temporomandibular joint

The absorbed doses and energy imparted during conventional radiography and tomography of the temporomandibular joint were examined. Absorbed doses from the lateral-oblique transcranial projection and lateral tomography were low (0.02 to 7 mGy). From the axial projection the thyroid gland and salivary glands received a substantial dose (15 to 54 mGy) which was considerably decreased using an improved design of collimator. Radiation to the lens of the eye for the transmaxillary projection and for frontal tomography was 3 to 8 mGy. This can be reduced by a factor of 25 using lead-glass eye shields. The mean energy imparted from a bilateral examination of the temporomandibular joints using axial projection, four exposures for the transcranial lateral-oblique views, two exposures in the transmaxillary projection and lateral tomography views using a multi-film cassette was 34 mJ. The axial projection accounted for 50% of this figure. (author)