Which of the following diagnostic studies emits ionizing radiation?
Select one:
a. fluoroscopy
b. MRI scan
c. pulse oximetry
d. ultrasound
The correct answer and explanation is:
Correct Answer: a. Fluoroscopy
Explanation:
Fluoroscopy is a type of medical imaging that uses ionizing radiation to create real-time moving images of the interior of the body. It is often used during diagnostic and interventional procedures, such as guiding the placement of catheters, evaluating gastrointestinal function, or visualizing blood flow. Because fluoroscopy uses X-rays, which are a form of ionizing radiation, it can expose patients and healthcare workers to radiation—especially during prolonged procedures.
Why the other options are incorrect:
- b. MRI scan (Magnetic Resonance Imaging)
MRI does not use ionizing radiation. Instead, it uses powerful magnets and radiofrequency waves to generate detailed images of organs and tissues. MRI is considered safer in terms of radiation exposure, though it can have other risks (e.g., with metal implants). - c. Pulse oximetry
This is a non-invasive method used to measure the oxygen saturation of a patient’s blood. It works by passing light through a fingertip or earlobe and measuring changes in light absorption. No radiation is involved at all. - d. Ultrasound
Ultrasound uses high-frequency sound waves to create images of the inside of the body. Like MRI, it does not involve ionizing radiation. It is commonly used in obstetrics, cardiology, and other fields for safe, real-time imaging.
Summary:
Fluoroscopy is the only choice among the listed diagnostic studies that emits ionizing radiation, specifically through the use of X-rays. Ionizing radiation has enough energy to remove tightly bound electrons from atoms, potentially leading to cellular damage. Therefore, while useful, fluoroscopy requires careful use to minimize exposure risks.