Improvement of Spatial Resolution and Reliability of rCBF Imaging in the Patients of Senile Dementia or Another Neuropsychologic Disease.

为提高断层局部脑血流(RCBF)图像的空间分辨率和rCBF值的可靠性，为改进Xe-133吸入法和环形单光子发射CT的rCBF成像，研制了一种新的准直仪系统和数据采集程序。新的准直器被设计成在1850MBq的Xe-133气体吸入下每像素获得100cpm。在新的方案中，准直器每旋转180度，探测器环的步进旋转角就改为1.4度。灵敏度为13.5Kcps/37KBq/m1，半高宽空间分辨率中心为13.6 mm，距20 cm圆柱体中心6 cm处为10.3 mm。这种新的准直仪系统能够提供更可靠的测量，特别是在大脑的深层结构。为了组成系统软件组件和患者数据库，介绍了一个硬盘(320MB)系统。为了评估我们改进的SPECT系统测量rCBF值的可靠性，我们分析了56例年龄在1.3岁到80岁之间的健康受试者的rCBF数据。五岁以下儿童的平均脑血流量大约是成年人的两倍。平均脑血流量随年龄增长迅速下降，女性22岁，男性24岁。此后缓慢下降，并与年龄呈负相关。在成人中，女性的平均脑血流量略高于男性，因此改进的rCBF定量方法对痴呆或其他神经心理疾病患者的诊断或随访研究是非常有力的工具。

An improvement of spatial resolution of tomographic regional cerebral blood flow (rCBF) image and the assessment of reliability of rCBF value were carried out.For an improved imaging of rCBF by Xe-133 inhalation method with a ring type single photon emission CT, a new collimator system and a data acquisition program were developed. The new collimator was designed to obtain 100cpm per pixel for 1,850MBq of Xe-133 gas inhalation. In the new program, the stepping rotaion-angle of the detector ring was changed into 1.4 degree for every 180 degree of collimator rotation. Sensitivity was 13.5Kcps/37KBq/m1 and the spatial resolution in FWHM was 13.6mm at the center and 10.3 mmat the 6cm apart from the center of 20cm cylindrical phantom. This new collimator system enabled to provide for more reliable measurement especially at the deep structure of the brain.To compose the system software assembly and patient detabase, a hard disk (320MB) system was introduced. And previous patient data was re-filled up.For an assessment of reliability of rCBF value with our improved SPECT system, The rCBF data measured in 56 healthy subjects who ranged in age from 1.3 to 80 years was analyzed. The mean CBF in children less than five years of age was about twice that found in adults. The mean CBF decreased rapidly with age until 22 years of age in females and 24 years of age in males. Thereafter, there was a slow decrease and a negative correlation with age was found. In adults, the mean CBF in females was slightly higher than that of males.Thus improved method for quantitative rCBF was very powerful tool for diagnosis or follow-up study especially in the patients with dementia or another neuropsychologic disease.