TI : The study of patient exposure and protection from dental radiography

 AU : Park TW
 AD : Dept. of Dental Radiology, College of Dentistry, Seoul National University
 SO : JKAMFR. 1979;9(1):25-31
 ISSN : 1225-049X
 LA : KOREAN
 CP : KOREA

 AB : The utilization of x-ray for diagnosis and examination is increasing by about 5~15% every year, therefore, it would be mandatory to protect the patients from exposures and so, studies in this field are performed even now. In dental field, the area of irradiation is limited any to the head and neck area, but the irradiated angle is varied following the objected tooth, so the adjacent structures lens and thyroid gland would be fragile to radiation.
 And the scattered radiation is one of the complicated problems in the protection because of specificity of dental x-ray and its object structures. The author, by using TLD(Thermoluminescent Dosimeter; Teledyne Isotopes Model 7300, Element; TLD 200(CaF2:Dy) and Capintec(Capintec Model 192, PM-30 Diagnostic chamber 28 ml active volume), tried a measurement of air dose distribution of the scattered radiation and the irradiated dose of lens and thyroid gland under the condition of taking the film on the left maxillary molar.
 The results were as follows:
 1. The half value layer of adapted dental x-ray machine was measured, and is 1.44mm Al.
 2. The time of irradiation on the left maxillary molar in the Alderson Rando Phantom, the measured doses of left and right lens, and thyroid gland were 8, 9 mR, 1, 2 mR and 2, 8 mR. Under the same conditions, the scattered radiation at the distance of 1 meter from the phantom were 84 μR at the front side, 11 μR at the back side, 18 μR at the right side and 72 μR at the left side.
 3. Under the same conditions, the dose showed higher value by about 5% in the presence of object(phantom) than in the case of absence.