Ishiguro Masanobu, Uno Masaki, Miyazaki Takuma, Kataoka Yumi, Toyama Hiroshi, Ichihara Takashi
Section of Radiology, Fujita Health University Hospital.
Graduate School of Health Sciences, Fujita Health University.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2018;74(2):124-132. doi: 10.6009/jjrt.2018_JSRT_74.2.124.
Iodine-labelled N-(3-fluoropropyl) -2β-carbomethoxy-3β-(4-iodophenyl) nortropane (I-FP-CIT) single photon emission computerized tomography (SPECT) images are used for differential diagnosis such as Parkinson's disease (PD). Specific binding ratio (SBR) is affected by scattering and attenuation in SPECT imaging, because gender and age lead to changes in skull density. It is necessary to clarify and correct the influence of the phantom simulating the the skull.
The purpose of this study was to develop phantoms that can evaluate scattering and attenuation correction.
Skull phantoms were prepared based on the measuring the results of the average computed tomography (CT) value, average skull thickness of 12 males and 16 females. I-FP-CIT SPECT imaging of striatal phantom was performed with these skull phantoms, which reproduced normal and PD. SPECT images, were reconstructed with scattering and attenuation correction. SBR with partial volume effect corrected (SBR) and conventional SBR (SBR) were measured and compared.
The striatum and the skull phantoms along with I-FP-CIT were able to reproduce the normal accumulation and disease state of PD and further those reproduced the influence of skull density on SPECT imaging. The error rate with the true SBR, SBR was much smaller than SBR.
The effect on SBR could be corrected by scattering and attenuation correction even if the skull density changes with I-FP-CIT on SPECT imaging. The combination of triple energy window method and CT-attenuation correction method would be the best correction method for SBR.
碘标记的N-（3-氟丙基）-2β-甲氧羰基-3β-（4-碘苯基）降冰片烷（I-FP-CIT）单光子发射计算机断层扫描（SPECT）图像用于帕金森病（PD）等疾病的鉴别诊断。在SPECT成像中，特异性结合率（SBR）受散射和衰减影响，因为性别和年龄会导致颅骨密度变化。有必要阐明并校正模拟颅骨的体模的影响。
本研究的目的是开发能够评估散射和衰减校正的体模。
根据12名男性和16名女性的平均计算机断层扫描（CT）值、平均颅骨厚度测量结果制备颅骨体模。使用这些颅骨体模对纹状体体模进行I-FP-CIT SPECT成像，再现正常和PD状态。对SPECT图像进行散射和衰减校正重建。测量并比较校正部分容积效应后的SBR（SBR）和传统SBR（SBR）。
纹状体和颅骨体模与I-FP-CIT一起能够再现PD的正常聚集和疾病状态，进一步再现颅骨密度对SPECT成像的影响。与真实SBR相比，SBR的错误率要小得多。
即使在SPECT成像中颅骨密度随I-FP-CIT变化，散射和衰减校正也可校正对SBR的影响。三能量窗法和CT衰减校正法相结合将是SBR的最佳校正方法。
