1.1 本试验方法包括测量医疗设备磁共振环境中静态磁场产生的磁感应转矩，并将该转矩与用户指定的验收标准进行比较。 1.2 本试验方法不解决其他可能的安全问题，这些问题可能包括但不限于磁感应偏转力、组织加热、设备故障、成像伪影、噪声、设备之间的相互作用以及设备和MR系统的功能。 1.3 这里考虑的转矩是由于MRI静态磁场与植入物磁化的相互作用而产生的静磁转矩。本试验方法未涉及由静态场与旋转装置中感应的涡流相互作用引起的动态扭矩。 本标准不涉及引线中电流引起的扭矩。 1.4 本标准中的方法适用于具有水平磁场的MR系统。本标准中描述的并非所有方法都适用于具有垂直磁场的MR系统。悬浮法和低摩擦表面法要求重力与磁感应扭转正交，并且可能不使用垂直磁场。扭转弹簧和皮带轮方法可适用于在垂直磁场中工作，但示例装置不适合在垂直磁场中使用。基于实测位移力法的计算与磁流变系统无关，因此可用于具有垂直磁场的磁流变系统。 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 该测试方法是确定医疗器械的存在是否会在磁共振环境中造成伤害所需的测试方法之一。 应解决的其他安全问题包括但不限于磁感应力（见试验方法 F2052 )，射频加热（见试验方法 F2182页 )和图像伪影（见测试方法 F2119 ). ISO TS 10974解决了MR环境中有源植入式医疗设备产生的危险。 5.2 术语MR Conditional、MR Safe和MR Unsafe以及实践中的相应图标 F2503 应用于标记设备在MR环境中的安全性。 5.3 与本试验相关的验收标准应合理。如果最大磁感应转矩小于医疗器械最长尺寸与其重量的乘积，则磁感应转矩小于因重力作用在器械上的最坏情况转矩。在这种情况下，假设应用磁感应转矩施加的任何风险不大于地球引力场中正常日常活动施加的任何风险。 这是保守的。更大的扭矩也可能不会造成危险。（例如，设备相对于相邻组织的位置、组织向内生长或其他机制可防止设备移动或由大于重力引起的扭矩的磁感应扭矩产生的力对相邻组织造成伤害。） 5.4 仅此测试方法不足以确定植入物在MR环境中是否安全。 5.5 本标准中考虑的磁感应转矩是由于MRI静态磁场与植入物中的磁化相互作用而产生的静磁转矩。本试验方法未涉及由静态场与旋转装置中感应的涡流相互作用引起的动态扭矩。导线中的电流也可能产生扭矩。

1.1 This test method covers the measurement of the magnetically induced torque produced by the static magnetic field in the magnetic resonance environment on medical devices and the comparison of that torque a user-specified acceptance criterion. 1.2 This test method does not address other possible safety issues which may include, but are not limited to, magnetically induced deflection force, tissue heating, device malfunction, imaging artifacts, acoustic noise, interaction among devices, and the functionality of the device and the MR system. 1.3 The torque considered here is the magneto-static torque due to the interaction of the MRI static magnetic field with the magnetization of the implant. The dynamic torque due to interaction of the static field with eddy currents induced in a rotating device is not addressed in this test method. Torque induced by currents in lead wires is not addressed by this standard. 1.4 The methods in this standard are applicable for MR systems with a horizontal magnetic field. Not all of the methods described in this standard are applicable for use in an MR system with a vertical magnetic field. The Suspension Method and the Low Friction Surface Method require gravity to be orthogonal to the magnetically induced torsion and may not be performed using a vertical magnetic field. The Torsional Spring and Pulley Methods can be adapted to work in a vertical magnetic field, however the example apparatus are not appropriate for use in a vertical magnetic field. The Calculation Based on Measured Displacement Force Method is independent of the MR system and thus could be used for an MR system with a vertical magnetic field. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method is one of those required to determine if the presence of a medical device may cause injury in the magnetic resonance environment. Other safety issues which should be addressed include but may not be limited to magnetically induced force (see Test Method F2052 ), RF heating (see Test Method F2182 ), and image artifact (see Test Method F2119 ). ISO TS 10974 addresses hazards produced by active implantable medical devices in the MR Environment. 5.2 The terms MR Conditional, MR Safe, and MR Unsafe together with the corresponding icons in Practice F2503 shall be used to mark the device for safety in the MR environment. 5.3 The acceptance criterion associated with this test shall be justified. If the maximum magnetically induced torque is less than the product of the longest dimension of the medical device and its weight, then the magnetically induced torque is less than the worst case torque on the device due to gravity. For this condition, it is assumed that any risk imposed by the application of the magnetically induced torque is no greater than any risk imposed by normal daily activity in the Earth's gravitational field. This is conservative. It is possible that greater torques also would not pose a hazard. (For example, device position with respect to adjacent tissue, tissue ingrowth, or other mechanisms may act to prevent device movement or forces produced by a magnetically induced torque that are greater than the torque due to gravity from causing harm to adjacent tissue.) 5.4 This test method alone is not sufficient for determining if an implant is safe in the MR environment. 5.5 The magnetically induced torque considered in this standard is the magneto-static torque due to the interaction of the MRI static magnetic field with the magnetization in the implant. The dynamic torque due to interaction of the static field with eddy currents induced in a rotating device is not addressed in this test method. Currents in lead wires may induce a torque as well.