A GPS ankle monitoring bracelet cannot be worn when getting an MRI under any circumstances.
The resolution may be hard or easy, depending upon whether the charge is federal or local, and whether the supervising officer is a pre-trial services officer or a parole officer. Generally ankle bracelets are prescribed by Federal pre-trial services officers in lieu of confinement when the patient allegedly is an escape risk. If the situation is pre-trial, a motion must be made to the judge (not the pre-trial service officer) requesting an exemption from the court order for a specified period of time, accompanied by a letter from a physician. The physician's letyter should state (1) the timeliness of the MRI is important and there is risk if the evaluation is delayed and (2) an explanation of the reason for the procedure. At the same time provide a copy to the prosecutor. In such a case you will probably not have to have the officer accompany you, but have the device removed at the office and report back 24 hours later to have it put back. Such permission is routinely approved. Ocasionally they may request an additional amount of bail for the period in which the device is removed, usually obtained from a bondsman,which shouldn't be too expensive. If they do request additional bail, you can ask them to reconsider if this constitutes a financial burden.
In the case of parole, the bracelets are not used that much, and the procedure to obtain approval for their removal is complex. Discuss this with your parole officer, if this is the case.
Well, the magnets are so powerful that they can pull that ankle detector off him, possibly resulting in injury to himself and damage to the machine. So, the solution is to (a) call the doc who is ordering the MRI and inquire about whether the test will interfere with the ankle bracelet (just to be sure I'm correct), and (b) call or go see the parole officer about getting permission paperwork done to allow him to take off the ankle bracelet for the procedure. In addition, sometimes cancer can be treated and monitored adequately with a CT scan. My general thoughts, tho, are as long as the MRI machine does not go over the legs and feet, could be it's okay to wear the bracelet; I just don't know precisely if this would be allowed at the hospital.