Division of Biomedical Engineering and Science, Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Phys Med. 2021 Feb;82:219-227. doi: 10.1016/j.ejmp.2021.02.008. Epub 2021 Feb 28.
To simulate radiofrequency (RF) burns that frequently occur at skin-skin and skin-bore wall contact points.
RF burn injuries (thumb-thigh and elbow-bore wall contacts) that typically occur on the lateral side of the body during 1.5 T magnetic resonance imaging (MRI) scans were simulated using a computational human model. The model was shifted to investigate the influence of the position of the patient in an MRI scanner. The specific absorption rate (SAR), electric field, and temperature were mapped.
Regarding the contact points located near the edge of the birdcage transmission coil, under the allowable maximum RF power exposure i.e., the average whole-body SAR at the safety limit value (2 W/kg), the 10-g-tissue-averaged SAR (SAR) at those points significantly increased for both the thumb-thigh (180 W/kg) and elbow-bore wall (48 W/kg) cases. Both values significantly exceeded the highest safety limit of the partial-body SAR (10 W/kg). The electric field, the square of which is proportional to SAR, was remarkably high near the edge of the birdcage transmission coil. The peak SAR for each injury case was associated with contact-point peak temperatures that reached 52 °C at approximately 1 min following RF exposure onset; a 1-min period of exposure to this temperature causes a first-degree burn.
We demonstrated high heat generation in RF burn injury cases in silico. The RF heating occurring on the lateral side of the body was strongly dependent on the electric field distribution, which is dominantly determined by an RF transmission coil.
模拟在射频（RF）与皮肤-皮肤和皮肤-体腔壁接触点经常发生的灼伤。
使用计算人体模型模拟在 1.5T 磁共振成像（MRI）扫描过程中，身体外侧经常发生的 RF 灼伤（拇指-大腿和肘-体腔壁接触）。模型被移动以研究患者在 MRI 扫描仪中的位置对其的影响。绘制了比吸收率（SAR）、电场和温度图。
对于位于鸟笼传输线圈边缘附近的接触点，在允许的最大 RF 功率暴露下，即安全限值（2 W/kg）下的全身平均 SAR，这些点的 10g 组织平均 SAR（SAR）对于拇指-大腿（180 W/kg）和肘-体腔壁（48 W/kg）两种情况都显著增加。这两个值都显著超过了部分身体 SAR 的最高安全限值（10 W/kg）。在鸟笼传输线圈边缘附近，电场非常高，其平方与 SAR 成正比。每个损伤病例的峰值 SAR 与接触点的峰值温度相关，在 RF 暴露开始后大约 1 分钟达到 52°C；暴露于该温度 1 分钟会导致一度灼伤。
我们在计算机上模拟了 RF 灼伤损伤病例中产生的高热。身体外侧的 RF 加热强烈依赖于电场分布，而电场分布主要由 RF 传输线圈决定。
