1992 Fiscal Year Final Research Report Summary
Active utilization of scatter for reducing patient dose in x-ray diagnosis
| Project/Area Number |
02680184
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Nuclear engineering
|
|---|
| Research Institution | Kyoto Institute of Technology |
|---|
Principal Investigator |
KANAMORI Hitoshi Kyoto Institute of Technology, Department of Electronics & Information Science, Professor, 工芸学部, 教授 (70027770)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Masao Osaka Prefectural College of Technology, Department of Electrical Engineering &, 助教授 (50149944)
NAKAMORI Nobuyuki Kyoto Institute of Technology, Department of Electronics & Information Science,, 工芸学部, 助手 (20107353)
|
|---|
| Project Period (FY) |
1990 – 1992
|
| Keywords | medical x-rays / patient dose / scattered x-rays / x-ray spectrum / lead collimator |
|---|
| Research Abstract |
(1)Primary X-Ray Spectra and Their Effects Electron energy distribution was computed by the Monte-Carlo technique, and Bremsstrahlung spectra were calculated using quantum theory. The results coincided well with the results of the Birch-Marshall model. An efficient measurement method of x-ray spectra emitted by a self-rectified generator was performed. When an x-ray tube voltage ripple exceeded 60 %, the beam quality was hardened and the beam quantity increased, contrary to expectation. From these results it was found that the patient dose decreased as the tube current increased when a 2-pulse x-ray generator was used.
(2)Measurement of Scattered X-Ray Spectrum An accurate measurement method of x-ray focal position was performed by using a pin-hole. As a result, accurate scatter spectra were obtained by using a conical lead collimator and beam stoppers.
(3)Contrast-Dose Diagram Effects of the scattered x-rays upon the image quality were investigated by measuring the radiographic contrasts of aluminium square-wave chart images, with various scatter fractions. As a result, a contrast-dose diagram was proposed. This diagram is very useful to determine exposure conditions, balancing of high image quality and low patient dose in clinical radiography. This diagram was successfully applied in radiographing a pituitry fossa.
|
