ObjectiveTo analyze the influencing factors for image quality of 18F-deoxyglucose (FDG) positron emission tomography (PET)/CT systemic tumor imaging and explore the method of control in order to improve the PET/CT image quality. MethodsRetrospective analysis of image data from March to June 2011 collected from 1 000 18F-FDG whole body tumor imaging patients was carried out. We separated standard films from non-standard films according to PET/CT image quality criteria. Related factors for non-standard films were analyzed to explore the entire process quality control. ResultsThere were 158 cases of standard films (15.80%), and 842 of non-standard films (84.20%). Artifact was a major factor for non-standard films (93.00%, 783/842) followed by patients’ injection information recording error (2.49%, 21/842), the instrument factor (1.90%, 16/842), incomplete scanning (0.95%, 8/842), muscle and soft tissue uptake (0.83%, 7/842), radionuclide contamination (0.59%, 5/842), and drug injection (0.24%, 2/842). The waste film rate was 5.80% (58/1 000), and the redoing rate was 2.20% (22/1 000). ConclusionComplex and diverse factors affect PET/CT image quality throughout the entire process, but most of them can be controlled if doctors, nurses and technicians coordinate and cooperate with each other. The rigorous routine quality control of equipment and maintenance, patients’ full preparation, appropriate position and scan field, proper parameter settings, and post-processing technology are important factors affecting the image quality.
ObjectiveTo improve health care quality and safety by monitoring the performance of PhilipsPrecedence Dual-head single photon emission computed tomography (SPECT). MethodsWith our own homemade point source and the center of rotation model, in accordance with NEMA standards and manufacturers' design conditions, these three indicators including energy peak position of the instrument, intrinsic uniformity and center of rotation were routinely tested between 2008 and 2012 for the Philips-Precedence Dual-head SPECT in our hospital. In addition, the quality control was performed twice a week, and every year the total number of quality control was basically the same. We calculated the results by the weighted average method. ResultsThe 5-year average energy peaks of detector 1 and 2 were (139.23±0.32) and (138.97±0.45) keV, respectively, and they were both within the range of reference values [(140±3) keV]. In addition, the results of center of rotation were also in the normal range, and kept stable. Based on the analysis of quality-control data, for detector 1, compared with the data of 2008, there was no significant diTherence for central field of vision (CFOV) and useful field of vision (UFOV) in these three years from 2009 to 2011 (P>0.05). The diTherence was only significant between data of 2008 and that of 2012 (P<0.05). For detector 2, compared with the data of 2008, there was no significant diTherence for CFOV and UFOV in 2009 and 2011(P>0.05), while there was significant diTherent in 2010 and 2012 (P<0.05). ConclusionThe uniformity of SPECT will gradually deteriorate with prolonged use. However, regular quality control and maintaining can keep the function stabilization, and enhance the availability rate.