摘要
目的探讨一种简单易行的单光子发射计算机断层(single-photon emission computed tomography,SPECT)全身扫描速度稳定性和空间分辨率的测试方法。方法①全身成像系统扫描速度稳定性测量,在准直器中心固定^(99)Tc^m点源(148MBq),以10、15、20和25 cm/min的扫描速度作全身扫描,记录所获得的点状源图像,作出垂直于移动方向10像素宽度内的计数剖面曲线并计算计数偏差百分数。②空间分辨率的测量,将相距100mm的两支^(99)Tc^m线源(各74MBq),分别垂直和平行于检查床运动方向水平放置,以10、15、20和25cm/min的扫描速度分别获得线源图像,以线扩展函数的半高宽表示分辨率,并比较15cm/min时带和不带散射校正对空间分辨率的影响。结果点状源图像上没有发现明显的放射性浓聚或稀疏影。不同扫描速度下计数偏差分别为(0.003±0.855)%、(0.001±1.126)%、(0.001±1.176)%和(0.000±1.287)%,最大计数偏差分别为2.9%、3.0%、2.9%和3.6%。探头平行和垂直于运动方向的空间分辨率分别为(12.20±0.32)mm与(11.85±0.19)mm。扫描速度为15cm/min时,有散射校正的分辨率为(12.46±0.16)mm,没有散射校正的分辨率为(12.49±0.20)mm,两者差异无统计学意义(P>0.05)。结论该SPECT设备速度稳定性好,空间分辨率满足临床需要。这种检测方法简便实用,同样适用于其他SPECT系统,是对SPECT常规质量控制的有益补充。
Objective To investigate a simple and easy method for measuring velocity constancy and spatial resolutions in SPECT whole-body imaging system.Methods ①To measure constancy of scanner speed,a point source of ^(99)T^mc (148MBq) was fixed in the center of collimator,and whole-body imaging was acquired at 10,15,20 and 25 cm/min individually.On the images of the point source,profile curves were created perpendicular to its moves direction within a width of 10 pixels and calculated percentage of count deviation.②To measure spatial resolution two line sources of ^(99)T^mc (74MBq) with a distance of 100 mm were placed vertically and in parallel with the bed moving direction and corresponding.Images were acquired respectively at speed of 10,15,20 and 25 cm/min.spatial resolutions were shown at full width at half maximum of line-spread function.Spatial resolutions of with or without scatter correction were compared at the rate of 15 cm/min.Results ①Whole-body imaging of point source has no apparent radioactivity concentration or sparseness,The percentage of count deviations were (0.003 ± 0.855)%,(0.001±1.126)%,(0.001±1.176)% and (0.000±1.287)% at different rates.The maximum deviations were 2.9%,3.0%,2.9% and 3.6% respectively.② Resolutions of detector were 12.20mm and 11.85mm in parallel and verticality motion.With and without scatter calibration,resolutions were (12.46 ±0.16) mm and (12.49±0.20) mm respectively; there was no significant difference.Conclusion The SPECT whole-body imaging system has good velocity constancy and scanning resolution.This simple and useful method is applicable for other SPECT system as well and serves as beneficial supplement to the routine quality control.
出处
《河北医科大学学报》
CAS
2009年第8期798-800,共3页
Journal of Hebei Medical University
