| Project/Area Number |
63480255
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | Shiga University Of Medical Science (1989)
Kawasaki Medical School (1988) |
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Principal Investigator |
MORITA Rikushi Shiga University of Medical Science, Radiology, Professor, 医学部, 教授 (60026896)
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| Co-Investigator(Kenkyū-buntansha) |
MURATA Kiyoshi Shiga University of Medical Science, Radiology, Lecturer, 医学部, 講師 (20127038)
SUZUKI Teruyasu Shiga University of Medical Science, Radiology, Lecturer, 医学部, 講師 (70115864)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1988: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | Bone Mineral / Osteoporosis / DPA / DEXA |
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| Research Abstract |
In the first year, some fundamental factors relevant to the DPA of lumbar spine with lateral projection were investigated; 1) Problems due to the high count rate caused by the direct incidence of photons into the detector, such as counting miss due to the limited resolving time of the detector, pile up and misplaced event count rate, 2)problems accompanied by the thickened body mass of tive lateral projection.
As for the first problem, high count rate caused by the direct incidence of photon could be satisfactorily resolved by using a specifically designed wedge shaped acryl filter placed on the back of examinees. Effects of beam liardning became apparent as the body thickness increased and was significantly high over the body thickens over 25cm for 44KeV and 30cm for 10OKeV. Spill over phenomenon also became prominent as the body thickness increased.
Minimal effective measuring time was 15min for the thickness of 30cm with CV<1.5%. Detectability was 62.5mg/cm^3 of K_2HPO_4 at 20cm of body thickness and 125mg/cm^3 at 30cm for 15mi. As for the data processing, 9 point smoothing with V-filter was proved to be satisfactory.
In the second year, clinical studies were performed by measuring the BMD of vertebral body and posterior portion of the lumbar spine separately with the lateral projection. Decreases in the BMD of the vertebral body was much prominent than those of the posterior portion associated with aging. Further more, aortil calc ification and other soft tissue calcification could be eliminated from the spine. Thus the lateral projection were proved to be much advantageous over the AP projection in many aspects from the clinical point.
At present, however, reproducibility was not enough, atid further elaboration for the repositioning should be necessary.
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