X-ray leakage during radiotherapy.
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Equipment Safety↗
Biomedical subjects
J T Shakeshaft
Publications and source records attributed to J T Shakeshaft.
In vivo dosimetry using diodes as a quality control tool--experience of 2 years and 2000 patients.
This paper reports the use of diodes as a quality control tool on more than 95% of patients undergoing megavoltage radiotherapy during the past 2 years. The paper describes a simple method for using the diodes, a number of possible pitfalls and a quality issue raised by the measurements. In general, the results have been reassuring with very few patients falling outside a +/- 5% action level.
Breast Neoplasms↗
Gamma-ray scattering for mandibular bone density measurement.
There has been considerable interest in the measurement of bone density in the mandible, either to study bone resorption following tooth loss or to determine the relationship between mandibular and skeletal bone mineral density. Measurements mostly have been made on dental radiographs but more significant correlations between mandibular and skeletal bone density have been obtained when more sophisticated techniques have been used, such as quantitative CT and dual energy X-ray absorptiometry. The present work investigates the feasibility of using gamma-ray scattering measurements to estimate mandibular bone density. Using a phantom to simulate the jaw, an 241Am source and a hyperpure germanium detector it is shown that bone density may be measured with a precision of about 1%.
Absorptiometry, Photon↗
Gamma-ray backscatter for body composition measurement.
The purpose of this study was to examine the potential of using backscatter information to assess regional body composition at selected sites. Two measurement techniques are examined: the measurement of the ratio of coherent to Compton scatter, and the measurement of the Compton scatter profile. Two possible applications are considered: the measurement of trabecular bone mineral density, and the measurement of the average fat/muscle ratio in a tissue volume. The results presented indicate that the analysis of coherent and Compton backscattered gamma-ray spectra from an 241Am source has the potential for measuring both trabecular bone mineral density and average fat/muscle ratio in a tissue volume, with a low absorbed dose to the subject.
Adipose Tissue↗