Measurement of bone density using I-125 computed tomography
Osteoporosis is a painful condition characterised by a reduced bone mineralisation resulting in an increased fracture risk. A precise measurement of skeletal mineral is important for early diagnosis and for monitoring the response to treatment. This thesis presents the design and evaluation of a spe...
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Open University
1985
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| Online Access: | http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370939 |
| Summary: | Osteoporosis is a painful condition characterised by a reduced bone mineralisation resulting in an increased fracture risk. A precise measurement of skeletal mineral is important for early diagnosis and for monitoring the response to treatment. This thesis presents the design and evaluation of a specialised scanner capable of measuring trabecular bone in the radius. The anatomy and physiology of bone and the changes related to ageing and bone disease are reviewed in Chapter 1. Chapter 2 decribes and compares the various non-invasive methods of bone measurement developed in the last 25 years. The most precise method was I-125 computed tomography of the peripheral skeleton. The principles and practical implementation of computed tomography are fully discussed in Chapter 3. Chapter 4 describes a single detector bone scanner and includes the design process, the hardware and the specialised computer software. The novel use of a variable translation speed was found to significantly reduce the measurement time per slice. To further reduce the scanning time a multi-detector version of the scanner was designed (Chapters 5 & 6). Slice measurements were acquired in about two minutes and the use of a scanning radiography permitted axial re-positioning to within 2mm. A technical evaluation of the scanner showed that the scanner had excellent inherent precision and that the radiation dose to the patient was very low (Chapter 7). A measurement technique was developed (Chapter 8) which enabled trabecular bone to be measured with a reproducibility of 0.5% in patients. Comparisons with spine measurements showed that the two sites were well correlated when similar proportions of trabecular and cortical bone were measured (Chapter 9). Osteoporotic patients were found to have lost proportionally greater amounts of trabecular bone. Provisional results from serial measurements indicate that bone may be lost in a step-like pattern. |
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