Make sure you have one industrial and one medical use of radioisotopes - Cobalt-60 should be referred to as an industrial radioisotope.
Anyway, for Tc-99m:
Benefits
- Short half life (~6 hours) means that cells are exposed to less radiation and hence, lowered risk of damage.
- Quickly removed from the body (biological half life of 1 day), lowering the patient's radiation exposure.
- Does not react or interact with any bodily processes making it non-toxic.
Tc-99m binds to red blood cells as a tracer, allowing blood clots to be identified and hence, rectified by other means.
- Tc-99m can be added to other compounds to bind to different molecules. Tc-99m can be mixed with a tin compounds to bind to glucose, showing areas of the body with high or low glucose concentration.
Problems
- Although exposure is short and Tc-99m is quickly removed from the body, it is still radiation exposure in the form of gamma rays which are high-energy and highly ionising. This means that gamma ray exposure can ionise molecules in the body such as DNA, causing defects in cells that can thence, result in cancers.
- Tc-99m has a short half life meaning that it cannot be transported long distances but rather, must be synthesised on-site. This increases the cost of Tc-99m as it requires relevant equipment to produce Tc-99m. This limits the use of Tc-99m to larger, wealthier hospitals such as Royal Prince Alfred Hospital in Sydney.