Mattei E, Triventi M, Calcagnini G, Censi F, Kainz W, Bassen H I, Bartolini P
Department of Technologies and Health, Italian National Institute of Health, Roma, Italy.
Phys Med Biol. 2007 Mar 21;52(6):1633-46. doi: 10.1088/0031-9155/52/6/006. Epub 2007 Feb 27.
The purpose of this work is to evaluate the error associated with temperature and SAR measurements using fluoroptic temperature probes on pacemaker (PM) leads during magnetic resonance imaging (MRI). We performed temperature measurements on pacemaker leads, excited with a 25, 64, and 128 MHz current. The PM lead tip heating was measured with a fluoroptic thermometer (Luxtron, Model 3100, USA). Different contact configurations between the pigmented portion of the temperature probe and the PM lead tip were investigated to find the contact position minimizing the temperature and SAR underestimation. A computer model was used to estimate the error made by fluoroptic probes in temperature and SAR measurement. The transversal contact of the pigmented portion of the temperature probe and the PM lead tip minimizes the underestimation for temperature and SAR. This contact position also has the lowest temperature and SAR error. For other contact positions, the maximum temperature error can be as high as -45%, whereas the maximum SAR error can be as high as -54%. MRI heating evaluations with temperature probes should use a contact position minimizing the maximum error, need to be accompanied by a thorough uncertainty budget and the temperature and SAR errors should be specified.
这项工作的目的是评估在磁共振成像（MRI）期间使用荧光温度探头对起搏器（PM）导线进行温度和比吸收率（SAR）测量时所产生的误差。我们对起搏器导线进行了温度测量，分别用25、64和128兆赫兹的电流进行激励。使用荧光温度计（美国Luxtron公司3100型）测量PM导线尖端的发热情况。研究了温度探头的有色部分与PM导线尖端之间不同的接触配置，以找到使温度和SAR低估最小化的接触位置。使用计算机模型来估计荧光探头在温度和SAR测量中产生的误差。温度探头的有色部分与PM导线尖端横向接触可使温度和SAR的低估最小化。此接触位置的温度和SAR误差也最低。对于其他接触位置，最大温度误差可能高达 -45%，而最大SAR误差可能高达 -54%。使用温度探头进行MRI加热评估时应采用使最大误差最小化的接触位置，需要附带详尽的不确定度预算，并应指明温度和SAR误差。
