1. What is Tc99m Radioactive Decay?

Technetium-99m (Tc99m) is a radioactive isotope commonly used in medical imaging. It decays with a half-life of 6 hours, following exponential decay kinetics. Understanding its decay is crucial for nuclear medicine procedures.

2. How Does the Calculator Work?

The calculator uses the radioactive decay equation:

Where:

• \( A \) — Remaining activity (mCi)
• \( A_0 \) — Initial activity (mCi)
• \( t \) — Time elapsed (hours)
• 6 — Half-life of Tc99m (hours)

Explanation: The equation describes how the activity decreases exponentially over time, with the rate determined by the half-life.

3. Importance of Tc99m Decay Calculation

Details: Accurate decay calculations are essential for determining the appropriate dosage for imaging procedures and ensuring patient safety while maintaining image quality.

4. Using the Calculator

Tips: Enter the initial activity in millicuries (mCi) and the time elapsed in hours. The calculator will determine the remaining activity.

5. Frequently Asked Questions (FAQ)

Q1: Why is Tc99m commonly used in medicine?
A: Tc99m has ideal properties for imaging: 6-hour half-life, 140 keV gamma emission, and ability to label various compounds.

Q2: How often should decay calculations be performed?
A: For clinical use, calculations should be made immediately before administration to ensure accurate dosing.

Q3: What's the physical half-life vs biological half-life?
A: This calculator shows physical decay (6 hours). Biological clearance (from the body) would require additional considerations.

Q4: Can this calculator be used for other isotopes?
A: No, this is specific for Tc99m. Other isotopes have different half-lives and would require different calculations.

Q5: How does decay affect image quality?
A: As activity decays, longer imaging times may be needed to maintain adequate counts, potentially affecting patient comfort and image resolution.