Physics 2 Quiz 3.1

An MR unsafe 1 object is considered to pose a potential or realistic risk or hazard to a patient or individual in the MR environment due to its ability to move or become dislodged. This means that the object could cause harm or injury if it were to shift or come loose during an MRI procedure. Therefore, the statement "MR unsafe 1 is an object that is considered to pose a potential or realistic risk or hazard to a patient or individual in the MR environment primarily as the result of movement or dislodgment of the object" is true.

The statement is true because the MR Safety white paper was indeed created with the purpose of offering guidance to MR imaging facilities on how to develop and implement safety policies and procedures. This document serves as a valuable resource for ensuring the safety of both patients and staff during MR imaging procedures.

Cochlear implants are electronic devices that help individuals with hearing loss. Since they are attracted to the magnetic field and can be magnetically or electronically activated, they can be adversely affected by the strong magnetic field generated during an MRI. Therefore, it is true that cochlear implants are contraindicated for MRI.

The statement is true because IEC/FDA limits for localized heating include a head normal mode limit of 38oC or 3.2W/kg. This means that the amount of localized heating that is considered safe for the head is limited to a temperature increase of 38 degrees Celsius or a specific absorption rate of 3.2 watts per kilogram. These limits are set to ensure that exposure to electromagnetic fields does not cause excessive heating in the head, which can be harmful to human health.

Zone IV is suitable for screened patients because in medical settings, zones are often designated to separate patients based on their level of infection or risk. Zone IV is typically reserved for patients who have been screened and cleared of any contagious diseases or infections. This ensures that patients in this zone are at a lower risk of spreading infections to others. Therefore, the correct answer is "Screened".

The MR scanner room contains a strong magnetic field that can interact with ferromagnetic objects, causing them to become projectiles and pose a safety risk. Clipboards, paper clips, coins, and tools can all contain ferromagnetic materials and should therefore not be brought into the MR scanner room.

Peripheral nerve stimulation refers to the effects experienced during MRI exams, specifically during IR sequences. These effects include mild cutaneous sensations and involuntary muscle contractions. Therefore, the statement is true.

It is acceptable to scan some patients with implanted pacer wires as long as the wires are close to the skin and not looped outside the chest. The decision to scan these patients should be made by the radiologist. Additionally, the patient should be informed to squeeze the panic ball if they experience any heating in the area.

Every implant or device must be tested under the exact conditions that it will experience during MR imaging. This means that the testing should replicate the specific magnetic field strength, radiofrequency pulses, and other parameters that the implant or device will encounter during an MRI scan. Testing under exact conditions is crucial to ensure the safety and compatibility of the implant or device with the MRI environment and to minimize any potential risks or adverse effects during the imaging procedure.

Facilities do not prefer to delay any exam of pregnant patients until after the third trimester. In fact, many exams can be safely performed during pregnancy, especially during the second trimester. However, certain exams that involve radiation, such as X-rays or CT scans, may be delayed until after pregnancy or alternative imaging techniques may be used. Additionally, obtaining written consent from the patient before any exam is a standard practice in healthcare settings, regardless of pregnancy. Therefore, the statement is false.

The term "MR conditional" refers to an item that has been tested and proven to be safe for use in a specific MRI environment under specific conditions. In this context, "No known" hazards means that there are no known risks or dangers associated with the item in the specified MRI environment. Therefore, the item is considered safe to use in that particular setting.

SAR stands for Specific Absorption Rate, which is a measure of the amount of radiofrequency energy absorbed by the body when using a mobile device. It is used to calculate the expected increase in body temperature during an average examination. The limits for SAR are calculated over a 10-minute time period. The correct answer is 3 W/kg, which means that the maximum allowed SAR value for the head during an average examination is 3 watts of radiofrequency energy absorbed per kilogram of body weight.

Zone IV access refers to a region where there is a risk of serious injury or death if unscreened non-MR personnel and/or ferromagnetic objects and equipment are allowed. This means that in Zone IV, it is dangerous for individuals without proper screening or non-MR compatible objects to enter, as the strong magnetic field can cause harm. Therefore, the correct answer is true.

All personnel exposed to the magnetic environment should be educated about the potential risks and hazards of the static magnetic field. This includes housekeeping personnel, patient nursing personnel, fire department personnel, and police personnel. These individuals may come into contact with the magnetic field in different ways and need to be aware of the precautions they should take to ensure their safety.

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The explanation for the given answer is that the statement is incorrect. The decision to scan or not to scan is not solely a medical one made by the technologist. It is a decision that involves multiple healthcare professionals, including the referring physician and radiologist, who consider various factors such as the patient's medical history, symptoms, and the potential risks and benefits of the procedure. The decision is made collaboratively and takes into account the individual circumstances of each case.

The correct answer is Safety associated with particular device and Torque and heating. This is because testing for an implanted device includes assessing its safety in relation to the specific device, as well as evaluating the torque and heating effects it may have. It is important to scan the device at the field strength it was tested for, as lower or higher field strengths may not have been evaluated for safety and may pose risks to the patient. Other factors such as artifacts, functionality of the device, and device interference with image quality may also be assessed during testing, but they are not the specific conditions mentioned in the question.