Which of the following involves the injection of radioisotopes into the body?

SCTIMST Staff Nurse - 2016

Medical & Surgical Nursing

Easy

Appeared in: SCTIMST Staff Nurse - 2016

Explanation

Positron Emission Tomography (PET) is a nuclear imaging technique that visualizes metabolic processes in the body.
It requires the intravenous injection of a radioactive substance (a radiotracer or radioisotope), such as Fluorodeoxyglucose (FDG).
The scanner detects the radiation (gamma rays) emitted from the tracer as it decays within the body's tissues.
This allows for the creation of images that show functional activity, such as glucose metabolism, which is often elevated in cancer cells.

Option A: Radiography, commonly known as an X-ray, uses external ionizing radiation to create images. It does not involve the injection of any substance into the body.
Option C: Computed Tomography (CT) imaging uses multiple X-ray beams from a rotating source to create cross-sectional images. While an intravenous contrast dye (often iodine-based) may be injected to enhance images, this dye is not a radioisotope.
Option D: Magnetic Resonance Imaging (MRI) uses powerful magnetic fields and radio waves to generate detailed images of soft tissues. It does not use ionizing radiation or radioisotopes. A contrast agent (like gadolinium) may be used, but it is not radioactive.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Medical Imaging Modalities and Use of Radioisotopes as background academic context rather than a clinical decision trigger.
Nurses preparing patients for a PET scan must provide specific instructions, such as fasting for 4-6 hours, avoiding strenuous exercise, and ensuring blood glucose levels are within an acceptable range, as high glucose can interfere with the FDG tracer.
Post-procedure, the nurse should encourage the patient to drink plenty of fluids to help flush the radioactive tracer from their body.
It is crucial to screen for pregnancy or breastfeeding, as the radioactive substance can be harmful to a fetus or can be passed through breast milk.

How to Approach the Question

First, identify the key term in the question: 'injection of radioisotopes'.
Next, recall the basic mechanism of each imaging modality listed in the options.
Radiography (X-ray) and CT use external X-rays. Eliminate these options.
MRI uses magnetic fields and radio waves, not radiation or radioisotopes. Eliminate this option.
PET (Positron Emission Tomography) is a nuclear medicine technique. The name itself implies a process involving particles (positrons) which are generated from radioactive decay.
Conclude that PET is the only option that fundamentally relies on injecting a radioactive substance to generate an image.

Concept Tested & Keywords

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