Why does Technetium-99m provide a low radiation dose compared to other isotopes?

• A. It has a long half-life
• B. It emits low energy particles
• C. It has a short half-life and high photon energy
• D. It is not radioactive

Answer: (C)

Technetium-99m is renowned for its low radiation dose, largely due to its short half-life and the specific characteristics of the photons it emits. The short half-life of approximately 6 hours means that the radioactive substance decays quickly, reducing the amount of time a patient is exposed to radiation. This rapid decay contributes to a lower overall radiation dose since the radioactive material is present in the body for a limited period.

Moreover, Technetium-99m is primarily used to emit gamma rays, which are highly penetrating but have low energy compared to other radiation types emitted by different isotopes. The combination of a short half-life and the emission of low-energy photons makes it advantageous for diagnostic imaging, as it produces sufficient signal for imaging while minimizing the radiation burden to the patient.

These characteristics make Technetium-99m particularly valuable in nuclear medicine, allowing for effective imaging with minimal risk to patient safety.