Question

Iodine- 131 is used to treat Graves disease, a disease of the thyroid gland. The amount of \({ }^{131} \mathrm{I}\) used depends on the size of the gland. If the dose is 86 microcuries per gram of thyroid gland, how many grams of \({ }^{131} \mathrm{I}\) should be administered to a patient with a thyroid gland weighing 20 g? Assume all the iodine administered accumulates in the thyroid gland.

Short answer

1720 microcuries of \rI \rshould be administered.

Step-by-step solution

Understand the problem

The problem provides the dosage rate of Iodine-131 required per gram of thyroid gland and the total weight of a patient's thyroid gland. The task is to calculate the total dosage of Iodine-131 needed for the entire gland.

Calculate total dosage required

Multiply the dosage rate by the weight of the thyroid gland to find the total amount of Iodine-131 needed for treatment: Total dosage (microcuries) = Dosage rate (microcuries/gram) x Gland weight (grams).

Perform the multiplication

Using the dosage rate of 86 microcuries per gram and the gland weight of 20 grams, multiply these values: Total dosage = 86 microcuries/gram x 20 grams = 1720 microcuries.

Key concepts

Iodine-131 Dosage Calculation

When faced with the serious task of treating Graves' disease, doctors often utilize Iodine-131, a radioactive isotope. Proper dosage is crucial to ensure efficacy while minimizing potential side effects. The dosage calculation is based on the radioactive decay principle used in nuclear chemistry.
To calculate the correct amount of Iodine-131 necessary for treatment, a specific dosage rate is prescribed by medical professionals, often measured in microcuries per gram of thyroid tissue. This rate is multiplied by the weight of the thyroid gland to ascertain the total dosage required for the patient.

Example:

In a scenario where the dosage rate is 86 microcuries per gram and the patient's thyroid gland weighs 20 grams, the calculation is straightforward:

• Total dosage = Dosage rate x Gland weight
• Total dosage = 86 microcuries/gram x 20 grams
• Total dosage = 1720 microcuries

This example exhibits the practical application of the calculation, an essential component for personalized and effective treatment for those suffering from Graves' disease.

Graves' Disease Treatment

Graves' disease, an autoimmune disorder leading to overactivity of the thyroid gland (hyperthyroidism), can cause significant health issues. Radioactive iodine therapy is one of the most common and effective treatments for this condition. It involves oral administration of Iodine-131, which targets and gradually destroys overactive thyroid cells, helping to restore normal function.
The therapy's success depends on a meticulously calculated dosage of Iodine-131, tailored to the individual's thyroid gland size. Ensuring the optimal dose requires precision as it affects the rate of radioactive decay and subsequent absorption by the thyroid cells.

Personalized Treatment:

By calibrating the dosage based on the gland's weight, specialists can tailor treatments that are highly personalized. This precision helps in avoiding destruction of healthy tissues and minimizes side effects, achieving a balance between therapeutic benefits and patient safety.

Nuclear Chemistry in Medicine

The field of nuclear chemistry plays a pivotal role in modern medicine, particularly in diagnostics and treatment. Using isotopes like Iodine-131 exemplifies the therapeutic use of radioactive substances. These isotopes undergo nuclear decay, emitting radiation that can be targeted to treat specific conditions, such as Graves' disease, or to diagnose ailments through imaging techniques like Positron Emission Tomography (PET) scans.
Iodine-131's effectiveness stems from its ability to emit beta particles, which are useful in eliminating overactive thyroid cells. The principles of nuclear chemistry enable the controlled use of radiation, making it a powerful tool for physicians.

Beyond Treatment:

Besides treatment, nuclear chemistry helps in the early detection of diseases, influencing patient outcomes positively. Isotopes in diagnostic radiopharmaceuticals illuminate the function and structure of organs, assisting in accurate diagnosis. The crossroads of chemistry, physics, and medicine has thus paved the way for advancements that have revolutionized patient care.