Radioactive nuclei that are injected into a patient collect at certain sites within its body, undergoing radioactive decay and emiting electromagnetic radiation can then be recorded by a detector. This procedure provides an important diagnostic tool called

Options

A. Gamma camera
B. CAT scan
C. Radiotracer technique
D. Gamma ray spectroscopy

Answer

To solve the question, we need to identify the diagnostic tool that utilizes radioactive nuclei injected into a patient, which then undergo radioactive decay and emit electromagnetic radiation that can be detected.

### Step-by-Step Solution:

1. **Understanding the Process**: The question describes a procedure where radioactive nuclei are injected into a patient. These nuclei collect at specific sites in the body and undergo radioactive decay, emitting electromagnetic radiation.

2. **Identifying the Purpose**: The emitted radiation can be detected, which suggests that this procedure is used for diagnostic purposes in medicine.

3. **Recognizing the Technique**: The technique that involves the use of radioactive substances to visualize and diagnose conditions in the body is known as a "tracer" technique.

4. **Defining the Tracer**: A tracer is a radioactive isotope that can be tracked through its decay and the radiation it emits. This allows medical professionals to observe the function of organs or tissues.

5. **Example of a Tracer**: One common example of a tracer in medical diagnostics is radioactive iodine-131, which is used to assess the function of the thyroid gland.

6. **Conclusion**: Based on the above points, the important diagnostic tool referred to in the question is called the "radio tracer technique."

### Final Answer:
The procedure provides an important diagnostic tool called the **radio tracer technique**.

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