Picture archiving and communications system in radiotherapy.

In recent years, the use of the Picture Archiving and Communications System (PACS) has become widespread in the area of diagnostic radiology for archival, review and reporting of patient data. However, the adoption of PACS within the field of radiotherapy is still very limited, despite the fact that most radiotherapy systems now use Digital Imaging and Communications in Medicine (DICOM) for both storage and communication. This paper discusses the challenges of integrating PACS into a radiotherapy department as a long-term archive of patient treatments. A possible solution based on a large English department is used as an example.

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.

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%.

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.

Gamma-ray scattering for fat fraction measurement.

The work reported examines the potential of using gamma-ray photon backscatter information to measure in vivo the percentage of fat in specific tissue volumes. 241Am gamma rays are used as the source and the backscatter detected with a hyperpure germanium detector, with ethanol (approximately 80% fat, 20% muscle) and water (muscle) being used as tissue substitutes. Two measurement techniques are examined; the measurement of the ratio of coherent scatter to Compton scatter and the measurement of the Compton scatter profile. Both are shown to be sensitive to the composition difference between ethanol and water. For the coherent-Compton scatter ratio, the measured difference between water and ethanol is 1.85:1, close to the value calculated (about 2:1). A similar difference in the coherent-Compton ratios between muscle and fat is calculated (2.2:1). The FWHM of the Compton profile has also been shown to vary with tissue composition with a difference of 0.10 keV (5%) between the ethanol and water profile widths.

Technical note: an X-ray fluorescence system for the determination of gold in vivo following chrysotherapy.

This paper describes a low cost mobile measurement system for the determination of gold in vivo base around a 153Gd radiation source and a hyper pure germanium detector. Early clinical results are also presented to demonstrate the efficacy of the system.

Spaced receiver observations of radio pulses.

Preliminary observations have been carried out to look for radio signals associated with gravitational waves. Although inconclusive, the observations from five receivers in the British Isles suggest the value of pressing on with further experiments.