A comparison of phosphate bone scanning agents in normal subjects and patients with malignant disease
None of the established bone scanning compounds 85Sr, 87Sr(m) or 18F is entirely satisfactory, and because of this, the role of skeletal scanning is not clearly defined. 18F is the most effective of the available bone scanning compounds, but its 100 min. half life makes distribution difficult. There has recently been considerable interest in certain compounds of phosphate which show great promise as bone scanning agents. The phosphate compounds polyphosphate, pyrophosphate and ethane hydroxy diphosphonate, are readily labelled with 99Tc(m) in the presence of the reducing agent stannous chloride. 99Tc(m) is one of the standard isotopes used in nuclear medicine. Its physical characteristics are ideal, and it is produced from a simple generator, on site. In 26 patients, the ratio of isotope activity in pathological areas relative to the isotope activity in adjacent or contralateral bone was measured directly from the gamma camera, using a multichannel analyser. This is referred to as 'tumor/bone ratio'. The results obtained with different phosphate compounds are discussed.