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目的探讨双探头ＳＰＥＣＴ仪采集中，由于投影位置偏差使２组图像连接处出现偏移，造成图像伪影与偏差的识别和校正。方法①模型采集：２只探头置成９０°（Ｌ模式）或１８０°（Ｈ模式）夹角，内插球形冷区的Ｊａｓｚｃｚａｋ模型和心肌灌注模型采集。用单探头采集的方法模拟投影偏差，关闭１只探头，在采集全过程的１／２处移动模型。②偏差探测：方法一是２只探头在同一角度采集点源图像，计算２幅点源矩心的偏差；方法二是在２只探头相邻的角度采集点源图像，计算２幅点源矩心的偏差。在１台ＳＰＥＣＴ仪上将这２种方法与移动探测软件进行比较测试。③偏差校正：对模型采集的所有偏差图像，采用移动校正软件进行校正。结果在Ｈ模式中，随着偏差增大，图像逐渐模糊和失真。Ｌ模式中靶心图显示，Ｙ方向偏差造成心尖部缺损伪影，Ｘ方向偏差造成多位置缺损伪影。２种偏差探测方法得到相同结果（Ｙ方向偏差＝３４５ｍｍ，Ｘ方向＝０），与移动探测软件结果一致。模型采集的所有偏差图像经过移动校正软件校正，重建后的图像或靶心图恢复正常，与没有偏差时相同。结论投影偏差导致图像伪影，其中Ｌ采集模式Ｘ方向大于６９ｍｍ偏差，Ｌ模式Ｙ方向和Ｈ模式大于１３８ｍｍ的偏差，将可能造成假阳性或假?
Objective To explore the double-probe SPECT acquisition, due to the projection position deviation so that the two sets of images at the junction offset, resulting in image artifacts and bias identification and correction. Methods ①Model collection: The two probes were placed in the 90 ° (L mode) or the 180 ° (H mode) angle. The Jaszczak model and the myocardial perfusion model were interpolated in the spherical cold zone. With a single probe acquisition method to simulate the projection deviation, turn off a probe, the entire process in the collection of 1/2 to move the model. ② Deviation detection: Method one is that two probes collect point source images at the same angle and calculate the deviation of two point source centroids. The second method is to collect point source images at two adjacent angles and calculate two point sources Deviation of heart. In a SPECT instrument these two methods and mobile detection software to compare the test. (3) Deviation correction: All deviations images collected by the model are corrected by moving correction software. As a result, in the H mode, the image gradually becomes blurred and distorted as the deviation increases. The L-mode target map shows that the Y-direction deviation causes apex defect artifacts and the X-direction deviation causes multi-position defect artifacts. The same result was obtained with the two kinds of deviation detection methods (Y direction deviation = 345 mm and X direction = 0), which is consistent with the result of the movement detection software. All the deviations images collected by the model were corrected by the movement correction software, and the reconstructed images or bull’s eye diagrams returned to normal with no deviation. Conclusions Projection errors lead to image artifacts, where the deviation of X-direction of X-mode is greater than 69mm, L-mode Y-direction and H-mode is greater than 138mm, which may cause false positive or false positives.