Ring Artifact on SPECT Image due to Arbitrary Position of PMT Malfunction D Prayogo (1), A T Oktaviana (1,2,*), M N Ramadhan (1), R Afiva (1), Z Nisa (1), A S Lubis (1), O T Cahayaputri (1), M R Ramadhan (1)
1) Study Program of Physics, Faculty of Mathematics and Sciences Military, Republic of Indonesia Defense University, Bogor, 16810, Indonesia
2) Department of Physics, Faculty of Mathematics and Sciences, Universitas Indonesia, Depok, 16424, Indonesia
*aditya.oktaviana[at]idu.ac.id
Abstract
To obtain high-quality images using SPECT (Single Photon Computed Emission Tomography) imaging, quality control (QC) is required. QC is periodically conducted on SPECT based on standard protocol. Ring artifact are one of the factors in determining optimal image quality. Uniformity is a parameter that determines the ring artifact on SPECT image, which can be appeared as full-ring or half-ring. Those artifact generated since one or more PMT (photomultiplier tubes) are malfunctioning. A copper sheet sizes 2 \times 2 cm^2 and thickness 1 mm attached on LEHR (Low Energy High Resolution) collimator in coordinates (x.y) depend from COR (Center of Rotation) of gamma camera was used to generate ring artifact during image acquisition using radioisotope TC-99m and Jaszczak phantom. The image obtained are half-ring shaped, which is not much different from the image results at coordinates (x, 0).
Keywords: PMT, QC, ring artifact, SPECT image, uniformity
