Wikstrom Johan, Isacsson Ulf, Johansson Bengt, Lennernäs B O
Department of Surgical Sciences, Section of Radiology, Uppsala University, Uppsala, Sweden.
Department of Immunology, Genetics and Pathology, Section of Medical Radiation Sci-ence, Uppsala University, Uppsala, Sweden.
Anticancer Res. 2017 Sep;37(9):4993-4996. doi: 10.21873/anticanres.11911.
BACKGROUND/AIM: Electromagnetic Positioning Systems (EMP) is a new position-ing technique in four-dimensional radiotherapy. Patients with implanted transponders may be referred for magnetic resonance imaging (MRI) making it important to establish the MR safety.
Oranges were prepared with transponders and imaged on a 3T MR scanner with different sequences. Computed tomography (CT) was performed as comparison. MR artifacts were assessed. An estimation of the maximum transponder de-flection force and heating was made.
The mean measured displacement of transponders was 0.1 mm (range=0.03-0.3 mm). Artifacts were observed adjacent to transponders using all sequences. The deflection force on the transponder in the gantry was less than 38 mN. No heating was observed.
The absence of any substantial movement, the weak measured deflection force and absence of observed heating speaks for the safe use of MR imaging with transponder 3T. Local artefacts makes evaluation impossible adjacent to transponders.
背景/目的：电磁定位系统（EMP）是四维放射治疗中的一种新的定位技术。植入应答器的患者可能需要进行磁共振成像（MRI）检查，因此确定MRI安全性很重要。
将装有应答器的橙子在3T MR扫描仪上用不同序列成像。作为对照进行计算机断层扫描（CT）。评估磁共振伪影。估算应答器的最大偏转力和发热情况。
应答器的平均测量位移为0.1毫米（范围=0.03-0.3毫米）。使用所有序列时，在应答器附近均观察到伪影。应答器在机架中的偏转力小于38毫牛。未观察到发热现象。
未出现任何明显移动、测得的偏转力较弱且未观察到发热现象，这表明在3T条件下使用带有应答器的磁共振成像具有安全性。局部伪影使得应答器附近无法进行评估。
