The efflux rate of 99mTc- Sestamibi is a kinetic phenomenon related to the response of cancer cells to chemotherapy and may be used to determine drug resistance. Measurement of efflux rate requires accurate quantitative SPECT imaging within the time constraints imposed by the kinetics of the process. Method: A phantom study, at activity concentrations typically found with 99mTc-Sestamibi in vivo, was undertaken to optimise the SPECT parameters and, in particular, to determine if 180 degrees acquisition arcs could be used for accurate quantitation. Results: Studies designed to evaluate statistical uncertainty (noise), contrast restitution and resolution of the datasets using different acquisition and reconstruction parameters, showed that 180 degrees SPECT using a 64x64 matrix, 6 degrees angular sampling and iterative reconstruction was optimal. Finer linear and/or angular sampling afforded negligible improvement in resolution, but markedly increased the statistical uncertainty. Comparison of 360 degrees and 180 degrees acquisitions utilising conventional filtered back projection and iterative reconstruction algorithms demonstrated that the statistical uncertainty was reduced to a greater extent for 180 degrees data collection. For 360 degrees (64x64) data acquisition statistical uncertainty decreased from 15 per cent to 11 per cent using the iterative algorithm whilst the 180 degrees (64x64) data showed a reduction from 20 per cent to 7 per cent and approached values obtained by planar imaging. Conclusion: It is concluded that 180 degrees acquisition arcs are a practical option for accurate quantitative SPECT kinetic imaging for a planned study of chemotherapy response in patients with lung cancer.
|Journal||Australian and New Zealand Society of Nuclear Medicine|
|Publication status||Published - 2003|