In which of the following radioactive isotopes `I -131` is not used?

Options

A. In the diagnosis of lever and kidney disorder
B. Treatment of thyroid diseases
C. Increasing absorption of calcium in the body
D. For locationg tumors in brain.

Answer

To determine in which of the following applications iodine-131 (I-131) is not used, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understand the Uses of I-131**:
- I-131 is a radioactive isotope commonly used in medical applications, particularly related to the thyroid gland and certain diagnostic procedures.

2. **Evaluate Each Option**:
- **Option A**: Detecting stones in the kidney.
- I-131 is indeed used in medical imaging to help detect kidney stones. This option is a valid use of I-131.

- **Option B**: Treating thyroid disorders.
- I-131 is widely recognized for its use in treating thyroid conditions, such as hyperthyroidism and thyroid cancer. This option is also a valid use of I-131.

- **Option C**: Increasing the absorption of calcium in the body.
- I-131 is not used for increasing calcium absorption. Calcium absorption is primarily influenced by vitamin D and other factors, not by iodine-131. This option does not represent a use of I-131.

- **Option D**: Diagnosing liver and kidney disorders.
- I-131 can be used in imaging techniques to help diagnose liver and kidney disorders. This option is a valid use of I-131.

3. **Conclusion**:
- Based on the evaluation, the only option where iodine-131 is not used is **Option C**: to increase the absorption of calcium in the body.

### Final Answer:
**Iodine-131 is not used to increase the absorption of calcium in the body (Option C).**

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