Design an Adaptive Quality Control Phantom to Optimize Integral and Differential Uniformity, Collimator Hole Angulation and Center of Rotation of SPECT

摘要

The main objective of this research is to introduce a newly developed device called “Adaptive Quality Control Phantom” (AQCP) designed to perform the QC tests. This paper describes complete details of the AQCP structure and its potential as a QC 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 simulate QC phantoms. Different tests that include systematic uniformity, collimator hole angulation and center of rotation were conducted by this device and the results, findings and differences of these tests were compared with the QC classic method tests. The performance of systematic uniformity test show a considerable reduction in the technologist dose compared to the IAEA-TECDOC-602 method. On the other hand the average error difference between two methods for evaluating uniformity parameters of uniform images is less than 0.07%. The collimator hole angulation for three collimators was measured by using a point source and computer-controlled cylindrical positioning, the results of which show that the measurement accuracy for absolute angulation errors is better than 0.047 (degrees) or ±0.024° . The Root Mean Square (RMS) of CHA for LEHR, LEHS and LEUHR collimators was measured to be 0.290° , 0.292° and 0.208° respectively. A method for center of rotation assessment is introduced by AQCP and the results of this proposed method as compared with the routine QC test and their differences are discussed in detail. Based on the discussion made in this paper regarding AQCP, the authors believe that this device is able to simulate QC phantoms.