【摘要】 目的 研究两种不同的衰减系数转换方法对正电子发射计算机断层显像/计算机体层扫描（PET/CT） 标准摄取值（SUV）测量值的影响。 方法 2009年11-12月，从经过PET/CT氟代脱氧葡萄糖（FDG）显像患者中选取20例，其口腔中均有金属假牙。以四段转换法和二段转换法重建全身衰减校正断层图像。分别选取3种高密度区域和7种低密度区域，测量其最大SUV和平均SUV，比较两种转换方法SUV测量值。 结果 平均SUV：二段转换法的3种高密度区域SUV降低，在7种低密度区域中，1种区域增高，1种区域降低（P值均lt;0.05）。最大SUV：二段转换法的2种高密度区域的SUV降低，在7种低密度区域中，1种区域增高，2种靠近高密度组织的区域降低（P值均lt;0.05）。 结论 二段转换法能降低高密度区域的SUV，可用于减小体内金属植入物和CT对比剂造成的过度校正。【Abstract】 Objective To explore the effect of two attenuation correction algorithms on PET/CT SUV measurement. Methods From November to December 2009, the PET Slice of 20 patients with metallic dental implant were reconstructed with four-and two-section algorithms respectively. Mean SUV and maximum SUV were measured in three high-density areas and 7 low-density areas. Paired t test were performed to compare the differences. Results Mean SUV: two-section algorithm produced significantly lower SUV in all the three high-density areas; in the 7 low-density areas, SUV increased obviously in one area and decreased apparently in one area (Plt;0.05). Maximum SUV: two-section algorithm produced significantly lower SUV in two high-density areas, SUV increased obviously in one area and decreased apparently in two areas which was adjacent to the high density areas (Plt;0.05). Conclusion Two-section algorithm produces lower SUV measurement value than the four-section algorithm does, and it is useful in PET/CT studies for patients with metallic dental implant and when CT contrast is used.
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.
ObjectiveUtilizing PDCA circulation to enhance the quality of single photon emission computed tomography (SPECT) in whole body bone scan (WBS). MethodsBased on a retrospective analysis of the quality of WBS in the first half of year 2012, advices and measurements to improve the quality were implemented by the technologists. In the following half year of 2012, monthly evaluation of the WBS quality were carried out to further improve the quality by focusing on fine details of the patient positioning, radiopharmaceuticals injection and image processing, etc. ResultsBy utilization of PDCA circulation, WBS quality in the latter half year of 2012 constantly improved. Further more, effective and improved technical procedures were extracted from scattered individual experience, which was expected to improve the WBS quality effectively in the long run. ConclusionApplication of PDCA circulation in SPECT in whole body bone scan improves the image quality, because it not only brings better communication and understanding between patients and physicians/technologists, but also enables better patient preparations and individualized procedures based on standard protocols.
ObjectiveTo investigate the effects of the operation of nuclear medicine technologists on the quality and efficiency of whole-body bone imaging with single-photon emission computed tomography (SPECT). MethodsWe collected all the data from patients who underwent whole-body bone imaging with SPECT in the whole year of 2012 in Department of Nuclear Medicine, West China Hopsital of Sichuan University.From January to June 2012, no intervention was made.Between July and December 2012, a formal training including vein puncture, image processing, and post image processing improving was made for the technologists on the operation of whole-body bone scan.The difference in incidence rate of artifacts between the first and second half of the year was analyzed by χ2 test. ResultsIn all the 12 424 whole-body bone scan patients, the first and second six months had respectively 5 920 and 7 186.And the artifacts incidence rates were 15.6% vs.8.9%(χ2=137.483, P < 0.001).In addition, the daywork efficiency was highly improved by 16.7%(48.5 patients/day vs.56.6 patients/day). ConclusionThe operation of the nuclear medicine technologists not only affects the quality of whole-body bone imaging but also improves the work efficiency.
This paper is aimed to assess the diagnostic value of MRI versus 99Tcm-methylene diphosphonate (99Tcm-MDP) bone scan (BS) for osseous metastases in patients with prostate cancer. The computer-based retrieval was conducted on PubMed, EMBASE, EBSCO, Web of Knowledge, the Cochrane Library and Ovid data bases to search for trials about diagnosing osseous metastases of prostate cancer with MRI and 99Tcm-MDP BS. Selected with time acceptance and time exclusion criteria, the data quality were evaluated with QUADAS quality assessment tool and collected. We used the Meta-Disc software to conduct meta-analysis, and then calculated the pooled sensitivity, specificity and diagnostic odds ratio (DOR), drew the summary receiving operating characteristic (SROC) curve, and measured the area under curve (AUC) and Q* value. Then five studies were included, involving 353 patients. The pooled sensitivity of MRI and BS was 0.95 (95% CI 0.90~0.98) and 0.67 (95% CI 0.58~0.75), respectively. The pooled specificity was 0.97 (95% CI 0.94~0.99) and 0.88 (95% CI 0.83~0.91), respectively. The pooled DOR was 402.99 (95% CI 119.05~1 364.15) and 23.85 (95% CI 1.32~431.48), respectively. The AUC was 0.990 1 and 0.624 1, respectively. The Q* was 0.958 7 and 0.593 8. It can well be concluded that MRI is more effective than 99Tcm-MDP BS in the diagnosis of osseous metastases in patients with prostate cancer.