COMPARISON OF ABSORBED DOSES RESULTING FROM VARIOUS INTRAORAL PERIAPICAL RADIOGRAPHY

전악 치근단 방사선사진 촬영시 촬영조건에 따른 흡수선량 변화에 대한 연구

This study was designed to measure the absorbed dose to organs of special interest from full mouth with intraoral film(l4 films) and to compare the five periapical techniques. Thermoluminescent crystals(TLD-100 chip) were located in brain, orbit, bone marrow of mandibular ramus, bone marrow of mandibular body, bone marrow of 4th cervical spine, parotid gland, submandibular gland and thyroid gland. X -ray machine was operated at 70kVp and round collimating film holding device(XCP) and rectangular collimating film holding device(Precision Instrument) were used. The distance from the X-ray focus to the open end of the collimator was 8 inch, 12 inch and 16 inch. The results were as follows : 1. The absorbed dose was the highest in bone marrow of mandibular body(5.656mGy) and the lowest in brain (0.050mGy). 2. Generally, the lowest absorbed dose was measured from 16 inch cylinder, rectangular collimating film holding device with paralleling technique. But, in bone marrow of mandibular body and the floor of mouth, the highest absorbed dose was measured from 12 inch cylinder, rectangular collimating film holding device with paralleling techniques. 3. Comparing of five intraoral radiographic techniques, it was appeared statistically significant reduction of the absorbed doses measured with rectangular collimating film holding device compared to XCP film holding device (P<0.05). 4. No statistically significant reduction in the absorbed dose was found as cylinder length was changed(P>0.05).