Evaluation of spatial resolution of a PET scanner through the simulation and experimental measurement of the recovery coefficient

PURPOSE In order to measure spatial resolution of a PET tomograph in clinical conditions, this study describes and validates a method based on the recovery coefficient, a factor required to compensate underestimation in measured radioactivity concentration for small structures. METHODS In a PET image, the recovery factors of radioactive spheres were measured and their comparison with simulated recovery coefficients yielded the tomographic spatial resolution. Following this methodology, resolution was determined in different surrounding media and several conditions for reconstruction, including clinical conditions for brain PET studies. All spatial resolution values were compared with those obtained using classical methods with point and line sources. RESULTS In each considered condition, spatial resolution of the PET image estimated using the recovery coefficient showed good agreement with classical methods measurements, validating the procedure. CONCLUSION Measurement of the recovery coefficient provides an assessment of tomographic spatial resolution, particularly in clinical studies conditions.