In order for an object to be a heating risk from the RF field, it needs to:

For an object to pose a heating risk from the RF (radiofrequency) field in an MRI environment, it is essential for it to form a conductive loop. When an object creates a conductive loop in the presence of an RF field, it can induce currents that may produce heat. This process is due to the interaction between the RF energy and the electrical properties of conductive materials within the object. As the RF field oscillates, the conductive loop can trap and concentrate this energy, leading to localized heating, which poses a safety risk to patients or personnel in the MRI suite.

Understanding the requirement for a conductive loop emphasizes the importance of assessing equipment and accessories prior to MRI scanning. Non-ferrous and non-metallic materials, while they may not attract a magnetic field, do not necessarily create the conditions required for RF-induced heating unless they also have conductive properties and form a suitable geometry for currents to circulate. Hence, the size of the object or its material composition alone does not determine the heating risk; the key factor is whether it can form a loop that interacts with the RF field.