1998 Fiscal Year Final Research Report Summary
DEVELOPMENT OF GLOBAL STANDARD PHANTOM TO OPTIMIZE DIGITAL
| Project/Area Number |
09671923
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
病態科学系歯学(含放射線系歯学)
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
YOSHIURA Kazunori Fact.of Dentistry, Dept.of Oral & Maxillofac.Radiol., KYUSHU UNIVERSITY Assistant Professor, 歯学部, 講師 (20210643)
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| Co-Investigator(Kenkyū-buntansha) |
YUASA Kenji Dentistry, Oral & Maxillofac.Radiol., KYUSHU UNIVERSITY Assistant Professor, 歯学部, 講師 (40136510)
NAKAYAMA Eiji Dentistry, Oral & Maxillofac.Radiol., KYUSHU UNIVERSITY Instructor, 歯学部, 助手 (60172467)
TOKUMORI Kenji Dentistry, Oral & Maxillofac.Radiol., KYUSHU UNIVERSITY Instructor, 歯学部, 助手 (40253463)
TANAKA Takemasa Dentistry, Oral & Maxillofac.Radiol., KYUSHU UNIVERSITY Instructor, 歯学部, 助手 (30163538)
KAWAZU Toshiyuki Dentistry, Oral & Maxillofac.Radiol., KYUSHU UNIVERSITY Instructor, 歯学部, 助手 (20294960)
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| Project Period (FY) |
1997 – 1998
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| Keywords | standard phantom / digital dental image / diagnostic accuracy / detectability |
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| Research Abstract |
The purpose of this investigation was to develop a standard phantom for dental radiography and to compare image quality of film and digitally acquired images.
First, an aluminum block of 12 steps with 7 holes covered by acrylic blocks was developed. This phantom was radio graphed with two types of films at 3 different tube voltages. The modified perceptibility curve was generated by counting maximum perceptible holes at each exposure. Optimum exposure level was determined from this curve and compared with that determined by means of the standard aluminum stepwedge and the preset time o the x-ray machine. The x-ray attenuation range for this phantom seemed to approximate clinical conditions. In addition, differences in image quality could be evaluated by means of the number of the holes seen in the phantom.
Next, 2 film systems and several digital intraoral systems were compared with regard to visual image quality through use of this phantom. Modified perceptibility curves were created and compared each other. All digital systems except the Digora system showed lower optimum optimum exposures than E-speed film. In all digital images without enhancement, however, the maximum number of perceptible holes was significantly lower than that for the film systems at that exposure. With contrast enhancement, all digital systems except the Sens-A-Ray system showed visibility superior to that of the film systems. With CDR, Digora, and Dixel systems, exposures could be reduced by a considerable amount, with greater retention of information than was associated with film.
These results strongly suggest that digital systems, if properly used, can exceed film systems in the detection of small mass changes.
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