Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen.
Siemens Healthcare A/S, Aarhus, Denmark.
Nucl Med Commun. 2021 Jan;42(1):107-112. doi: 10.1097/MNM.0000000000001312.
CARE Dose 4D modulates mAs through several mechanisms according to patient size and shape, whilst maintaining user-defined reference image quality on Siemens Symbia single-photon emission computed tomography (SPECT)-computed tomography (CT) systems. A 20 kg child reference was used in child protocols prior to software version VB10 and a 75 kg adult thereafter. Quality reference mAs conversion factors are estimated for delivering equivalent mAs to children between two comparable SPECT-CT systems using adult and child references for topogram-based patient-size-related dose level adaptations.
A child phantom was scanned using child protocols on a Siemens Symbia T16 (child reference) and a Siemens Symbia Intevo Bold (adult reference). On each system, scans of the thorax, abdomen and pelvis were acquired with arms up and down, at 80 and 110 kVp. Quality reference mAs settings of 10-50 were used on the Symbia T16 and 40-200 on the Symbia Intevo Bold. These data were used to propose quality reference mAs (adult/child reference) conversion factors according to scan range, arm position and tube voltage.
Quality reference mAs for child protocols using the adult reference should multiply the child quality reference mAs by the following factors, to give comparable delivered mAs: arms up 80 kV: 3.8 (thorax), 3.8 (abdomen), 4.3 (pelvis); arms up at 110 kV: 3.8 (thorax), 4.1 (abdomen), 4.6 (pelvis); arms down at 80 kV: 4.0 (thorax), 3.7 (abdomen), 3.9 (pelvis); arms down at 110 kV: 4.3 (thorax), 4.0 (abdomen), 4.2 (pelvis).
Conversion factors for child to adult dose modulation references are proposed, allowing comparable delivered mAs to a child.Video abstract: http://links.lww.com/NMC/A178.
根据患者体型和形状，CARE Dose 4D 通过多种机制调节 mAs，同时维持西门子 Symbia 单光子发射计算机断层扫描（SPECT）-计算机断层扫描（CT）系统上用户定义的参考图像质量。在软件版本 VB10 之前，儿童方案中使用 20 公斤儿童参考，之后使用 75 公斤成人参考。对于使用成人和儿童参考进行基于体层摄影的患者体型相关剂量水平调整，以在两个可比的 SPECT-CT 系统之间为儿童提供等效 mAs，估计质量参考 mAs 转换因子。
使用西门子 Symbia T16（儿童参考）和西门子 Symbia Intevo Bold（成人参考）上的儿童方案对儿童体模进行扫描。在每个系统上，以手臂上举和下举的方式，在 80 和 110 kVp 下采集胸部、腹部和骨盆的扫描。Symbia T16 上使用 10-50 的质量参考 mAs 设置，Symbia Intevo Bold 上使用 40-200 的质量参考 mAs 设置。这些数据用于根据扫描范围、手臂位置和管电压提出质量参考 mAs（成人/儿童参考）转换因子。
使用成人参考的儿童方案的质量参考 mAs 应乘以以下因子，以给出可比的输送 mAs：手臂上举 80 kV：3.8（胸部）、3.8（腹部）、4.3（骨盆）；手臂上举 110 kV：3.8（胸部）、4.1（腹部）、4.6（骨盆）；手臂下举 80 kV：4.0（胸部）、3.7（腹部）、3.9（骨盆）；手臂下举 110 kV：4.3（胸部）、4.0（腹部）、4.2（骨盆）。
提出了儿童至成人剂量调节参考的转换因子，允许为儿童提供可比的输送 mAs。视频摘要：http://links.lww.com/NMC/A178。
