Acrylic Tc-99m Flood Field Phantom for the Quality Control of a Cardiac Single Photon Emission Computed Tomography

Abstract

Background and Objective: It is necessary to daily perform the quality control of a cardiac single photon emission computed tomography (cardiac SPECT) before the diagnosis use with patients. Flood filed phantom is the main equipment used in the examination. It contains Cobalt-57 radioisotope and is used as a standard source. Because of its half-life is short (271 days), it is needed to be replaced every two years, and at an expensive price. Therefore, the aim of this work is to study and design a flood field phantom using acrylic—which can be molded—with the use of radioactive technetium-99m.

Methods: The designed and created phantom will be tested with the quality control of cardiac SPECT. The results were then compared with the recommended values and the measures using Co-57 flood field phantom. The examinations included of the maximum energy (photo-peak), the energy resolution and the uniformity.

Results: The result showed that the mean value of the maximum power of Tc-99m was 140.48+1.5 keV which was in the recommended range. The mean value of the energy resolution was 5.77% which was in the standard range of <7.5%. However, the mean value of the uniformity was 64.01%, which is lower than the recommended value of > 91%.

Conclusion: Only two measured values from acrylic Tc-99m flood filed phantom were in the recommended ranges which were photo-peak and energy resolution. Nevertheless, the error of uniformity was ​​higher than the acceptable value. Therefore, the acrylic Tc-99m flood field phantom cannot replace the typical Co-57 flood phantom. Further studies might be performed by the use of other materials.