Medical Physics, Clínica Universidad de Navarra, Pamplona, Spain; IdisNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain.
IdisNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain; Nuclear Medicine, Clínica Universidad de Navarra, Pamplona, Spain.
Phys Med. 2021 Apr;84:1-9. doi: 10.1016/j.ejmp.2021.03.019. Epub 2021 Mar 31.
To investigate within phantoms the minimum CT dose allowed for accurate attenuation correction of PET data and to quantify the effective dose reduction when a CT for this purpose is incorporated in the clinical setting.
The NEMA image quality phantom was scanned within a large parallelepiped container. Twenty-one different CT images were acquired to correct attenuation of PET raw data. Radiation dose and image quality were evaluated. Thirty-one patients with proven multiple myeloma who underwent a dual tracer PET/CT scan were retrospectively reviewed. F-fluorodeoxyglucose PET/CT included a diagnostic whole-body low dose CT (WBLDCT: 120 kV-80mAs) and C-Methionine PET/CT included a whole-body ultra-low dose CT (WBULDCT) for attenuation correction (100 kV-40mAs). Effective dose and image quality were analysed.
Only the two lowest radiation dose conditions (80 kV-20mAs and 80 kV-10mAs) produced artifacts in CT images that degraded corrected PET images. For all the other conditions (CTDI ≥ 0.43 mGy), PET contrast recovery coefficients varied less than ± 1.2%. Patients received a median dose of 6.4 mSv from diagnostic CT and 2.1 mSv from the attenuation correction CT. Despite the worse image quality of this CT, 94.8% of bone lesions were identifiable.
Phantom experiments showed that an ultra-low dose CT can be implemented in PET/CT procedures without any noticeable degradation in the attenuation corrected PET scan. The replacement of the standard CT for this ultra-low dose CT in clinical PET/CT scans involves a significant radiation dose reduction.
在体模中研究允许用于准确校正 PET 数据衰减的最小 CT 剂量,并量化在临床环境中纳入该 CT 时的有效剂量降低。
在大型平行六面体容器内扫描 NEMA 图像质量体模。采集 21 个不同的 CT 图像以校正 PET 原始数据的衰减。评估辐射剂量和图像质量。回顾性分析 31 例经证实患有多发性骨髓瘤的患者,他们接受了双示踪剂 PET/CT 扫描。F-氟脱氧葡萄糖 PET/CT 包括诊断全身低剂量 CT(WBLDCT:120kV-80mAs),C-蛋氨酸 PET/CT 包括用于衰减校正的全身超低剂量 CT(WBULDCT)(100kV-40mAs)。分析有效剂量和图像质量。
只有两个最低辐射剂量条件(80kV-20mAs 和 80kV-10mAs)在 CT 图像中产生伪影,从而降低了校正后的 PET 图像质量。对于所有其他条件(CTDI≥0.43mGy),PET 对比恢复系数变化小于±1.2%。患者从诊断 CT 中接受中位数剂量为 6.4mSv,从衰减校正 CT 中接受中位数剂量为 2.1mSv。尽管 CT 图像质量较差,但 94.8%的骨病变仍可识别。
体模实验表明,在 PET/CT 程序中可以实施超低剂量 CT,而不会对衰减校正的 PET 扫描产生任何明显的退化。在临床 PET/CT 扫描中用这种超低剂量 CT 替代标准 CT 可显著降低辐射剂量。