Keith Boddy

A high sensitivity dual-detector shadow-shield whole-body counter with an 'invariant' response for total body in vivo neutron activation analysis

The development of a dual-detector shadow-shield whole-body counting system of high sensitivity is described. The sensitivity and performance of the counter are analysed, with specific references to total body in vivo neutron activation analysis, and shown to be at least comparable with those of many conventional shielded-room counters.

Measurement of calcium in sections of a human skeleton using a reactor spectrum-in vivo activation analysis technique

Factors influencing the precision of measuring changes in the calcium content of sections of bone, including vertebrae, using reactor neutrons for partial body in vivo activation analysis have been examined and quantified. These factors include (a) the choice of incidient neutron spectrum, (b) the uniformity of activation with depth in the body, (c) reproducibility, (d) interfering reactions, (e) sensitivity and (f) dosimetry. It is concluded that an overall precision of 2.8%-3.2% (coefficient of variation) can be attained with a neutron dose of 50 mrad or 3-4% with a dose as low as 20 mrad.

The development of a facility for partial body in vivo activation analysis using californium-252 neutron sources

Consideration of the nuclear and physical properties of 252Cf, which is spontaneously fissile, suggests that it is a very suitable radioisotopic source of neutrons for partial body i n vivo activation analysis. A facility is described, which has been developed for use in the clinical environment, and is both simple in construction and operation and economical. The performance in the measurement of intrathyroidal iodine and of calcium in various bones, including the vertebrae, is evaluated with respect to uniformity of activation, sensitivity, reproducibility (precision) and dosimetry. The findings suggest that this new technique will be suitable for clinical measurements in the hospital.

Measurement of neutron fluence in total body in vivo neutron activation analysis

A simple method of measuring neutron fluence by simultaneous activation of Cu bars attached to the motor-driven bed adjacent to the patient is described.

Some Practical Advantages of Sealed Tube 14 MeV Neutron Generators for Total Body in vivo Activation Analysis

Summarizes the practical advantages of using for this purpose, two sealed tube 14 MeV neutron generators with a scanning geometry in conjunction with a shadow-shield whole body counter. The requirements of neutron sources for TBIVAA include: uniformity of fast and thermal neutron fluence through the body, the simultaneous measurement of as many body elements as possible, especially Ca, P, N, Na and Cl; an acceptable neutron dose; reproducibility; an irradiation procedure causing as little inconvenience and trauma as possible to the patient; and acceptable costs.

An evaluation of 57Co-labelled vitamin B12 in a double tracer test of absorption using a whole-body monitor.

57Co-labelled vitamin B12 (0.25 µg; 0.25 µCi) has been used in a double tracer test of absorption, together with 58Co-labelled vitamin B12 (0.4 µg; 0.4 µCi), using a whole-body monitor. It was found that variation of the counting-rate on the day of administration was small and was similar for both isotopes. The fraction of 58Co γ-rays detected in the 57Co energy band also showed little variation and the patient was able to act as his own phantom. The range of absorption of vitamin B12 was 21.3-63.3% in control subjects and 1.8-11.8% in patients with pernicious anaemia. The absorption of vitamin B12 with intrinsic factor, determined simultaneously, was always at least twice the absorption of vitamin B12 alone in patients with pernicious anaemia and always less than twice in control subjects. The results demonstrate the suitability of 57Co-labelled vitamin B12 in whole-body monitoring studies of vitamin B12 metabolism.