Results of the Measurement of the Collimator Hole Angulation for Different Collimators of SPECT with Adaptive Quality Control Phantom

Abstract

The Adaptive Quality Control Phantom (AQCP) is the computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produce any spatial distribution of gamma rays to perform the QC Tests such as the Collimator Hole Angulation (CHA) of Single Photon Emission Computer Tomography (SPECT). The collimator hole angulation for seven collimators were measured with the method by using a point source and computer-controlled cylindrical positioning. In this method the displacement of the image of a point source examined as the AQCP move point source vertically away from the collimator face. The results of the high-accuracy measurement method of CHA show that the measurement accuracy for absolute angulation errors is better than ±0.024°. The Root Mean Square (RMS) of CHA for LEHR, LEHS, LEUHR, MEGP-250, MEGP-300, MEGP-360 and HEPH collimators of SMV dual heads camera were measured to be 0.290°, 0.292°, 0.208°, 0.194°, 0.181°, 0.177°, 0.150°, respectively. The Root Mean Square (RMS) of CHA for LEGP, MEGP and HEGP collimators of GE Millennium MG were measured to be 0.154°, 0.220° and 0.202° respectively. It is to be added in this connection that the measured RMS of CHA for LEHR collimator with the distance variation from the collimator’s surface +/– 1 mm has been varied +/– 0.04 degree.