Variation of image counts with patient anatomy and development of a Monte Carlo simulation system for whole-body bone scans

• Main Author: McGurk, Ross James
• Language: en
• Published: University of Canterbury. Physics and Astronomy 2008
• Subjects: Monte Carlo modelling; nuclear imaging; whole body; gamma camera; anthropomorphic phantom; NCAT phantom; SIMIND
• Online Access: http://hdl.handle.net/10092/1586

The optimisation of image quality in medical imaging techniques is a significant factor in favourable patient prognoses. The number of counts in a nuclear medicine image is one factor in determining the diagnostic value of the image. The current study aims to determine the variation in counts in whole-body bone scan images with patient height and weight. Three separate studies were undertaken as part of the investigation. First, 65 whole-body bone scans were analysed together with patient height, weight, age and sex. Weight was found to the most important anatomy influence on image counts. However, significant influences from patient sex and age meant that a useful relationship between image counts and patient anatomy based solely on height and weight could not be determined. For the second study, a model of General Electric Millennium MG gamma camera was created and validated within the SIMIND Monte Carlo software. The results indicate that the model is an accurate representation of the gamma camera. Third, the 4D NCAT whole-body patient phantom was modified to represent the average male and female clinical study participants. The phantoms were used in conjunction with the gamma camera model to simulate the whole-body bone scan procedure. The counts in the simulated images were consistent with the average measured counts of the clinical study indicating that it is feasible to use the NCAT phantom for nuclear medicine bone imaging. However, the phantom’s method of activity distribution should be refined to allow a more realistic distribution of activity throughout the skeleton.