Unit 5: Radiopharmaceuticals

February 14, 2026

Semester 1
BP104T

Introduction to Radiopharmaceuticals

Unit 5 deals with ‘Nuclear Pharmacy’. It covers the physics and chemistry of radioactive substances used in medicine. You will learn about the types of radiation (Alpha, Beta, Gamma), the concept of Half-life, and the clinical use of radioisotopes like Sodium Iodide (I-131) for thyroid treatment. Safety and storage are critical components of this unit.
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Syllabus & Topics

  • 1Radiopharmaceuticals: Radioactivity, Measurement of radioactivity (Geiger-Muller Counter)
  • 2Properties of α, β, γ radiations
  • 3Half-life and its significance
  • 4Radioisotopes and study of radioisotopes – Sodium Iodide I-131
  • 5Storage conditions & precautions for radioactive substances
  • 6Pharmaceutical application of radioactive substances (Diagnosis & Therapy)

Learning Objectives

Define Radioactivity and Half-life.
Compare the properties of Alpha, Beta, and Gamma radiations.
Describe the clinical applications of Sodium Iodide I-131.
List the precautions for handling and storage of Radiopharmaceuticals.

Frequently Asked Questions (FAQs)

Q1. What is Radioactivity?

Radioactivity is the spontaneous emission of ionizing radiation or particles from the unstable nucleus of a radioactive isotope (radioisotope) in order to attain a stable state.

Q2. What is Half-life?

The half-life (t½) of a radioactive isotope is the time required for half of the radioactive atoms present originally to undergo decay. It is a constant and characteristic property of each radioisotope.

Q3. What is Sodium Iodide I-131 used for?

Sodium iodide (I-131) is used in the diagnosis and treatment of thyroid disorders, such as hyperthyroidism and thyroid cancer, because the thyroid gland selectively absorbs iodine.

Q4. What are Alpha, Beta, and Gamma rays?

  • Alpha (α) rays: Helium nuclei with low penetrating power

  • Beta (β) rays: High-speed electrons with moderate penetrating power

  • Gamma (γ) rays: Electromagnetic radiation with very high penetrating power

Q5. What are the precautions for handling radioactive substances?

Precautions include wearing lead aprons and gloves, using remote handling forceps, storing materials in lead-lined containers, monitoring exposure with Geiger–Muller counters, and disposing radioactive waste according to safety regulations.