Takehisa Nagasaka1, Masahiro Izumi2, Kenichi Gotoh3, Tsutomu Kuwada3, Yoshitaka Kise1, Akitoshi Katsumata4, Eiichiro Ariji1. 1. 1 Department of Oral and Maxillofacial Radiology, Aichi-Gakuin University School of Dentistry , Nagoya , Japan. 2. 2 Department of Dentmaxillofacial Diagnosis and Treatment , Kanagawa Dental University , Yokosuka , Japan. 3. 3 Division of Radiological Technology, Dental Hospital, Aichi-Gakuin University , Nagoya , Japan. 4. 4 Department of Oral Radiology, Asahi University School of Dentistry , Hozumi , Japan.
Abstract
OBJECTIVES: To verify the use of tungsten sheet as an alternative to lead foil for reducing the radiation dose behind storage phosphor plates (SPPs). METHODS: At six sites (incisor, canine, and molar sites in both the maxilla and mandible) in a head phantom, radiation doses were initially measured behind conventional film packets containing two films and a lead foil. At the same sites, radiation doses were also measured behind packets containing only SPPs. Thereafter, the same dose measurements were performed with shielding materials (lead foil or tungsten sheet) within the packets. These doses were defined as behind doses. RESULTS: There were no differences in the mean behind doses between the conventional film packets and the SPP packets without shielding materials for any of the six sites examined. The behind doses were reduced by both lead foil and tungsten sheet, with significant differences in all sites when compared with no shielding. Lead foil reduced the behind dose of the SPP packet to 37.6% on average, while tungsten sheet reduced the behind dose to less than 20% in all of the sites examined, with an average of 14.7%. CONCLUSIONS: Tungsten sheet appeared to be effective as an alternative shielding material, sufficiently reducing the doses behind the SPP packets to less than 20% when compared with sheetless packets in all of the six sites examined.
OBJECTIVES: To verify the use of tungsten sheet as an alternative to lead foil for reducing the radiation dose behind storage phosphor plates (SPPs). METHODS: At six sites (incisor, canine, and molar sites in both the maxilla and mandible) in a head phantom, radiation doses were initially measured behind conventional film packets containing two films and a lead foil. At the same sites, radiation doses were also measured behind packets containing only SPPs. Thereafter, the same dose measurements were performed with shielding materials (lead foil or tungsten sheet) within the packets. These doses were defined as behind doses. RESULTS: There were no differences in the mean behind doses between the conventional film packets and the SPP packets without shielding materials for any of the six sites examined. The behind doses were reduced by both lead foil and tungsten sheet, with significant differences in all sites when compared with no shielding. Lead foil reduced the behind dose of the SPP packet to 37.6% on average, while tungsten sheet reduced the behind dose to less than 20% in all of the sites examined, with an average of 14.7%. CONCLUSIONS:Tungsten sheet appeared to be effective as an alternative shielding material, sufficiently reducing the doses behind the SPP packets to less than 20% when compared with sheetless packets in all of the six sites examined.