„Radioactive” certainly isn’t the first word that comes to mind when thinking about medical waste. However, as most types of biomedical waste can already be considered a biohazard or infectious, it shouldn’t come as too much of a surprise that hospitals and other healthcare facilities also use radioactive materials during diagnostic and treatment methods. In the following article, we’ll cover exactly what kind of radioactive medical waste may be generated in medical facilities, as well as what the best options are for the segregation and the safe handling of such waste.
What is radioactive medical waste? - Examples
If a hospital (or any other kind of healthcare facility) has its own section for nuclear medicine, – and if it employs effective medical waste management systems, then it really should – then that is where procedures associated with radiation therapy will take place. There are many types of radioactive medical waste, but basically anything that comes into contact with trace amounts of certain isotopes, or a stronger radiation source (such as medical equipment, packaging materials, washing fluids, paper wipes, or even clothing) can be considered as such.
Specific examples regarding radiation sources include:
- Fluorine-18 (F-18) – with a half-life of 110 minutes
- Technetium-99 (T-99m) – with a half-life of 6 hours
- Iodine-131 (I-131) – with a half-life of 8 days
- Strontium-89 (Sr-89) – with a half-life of 52 days
- Iridium-192 (Ir-192) – with a half-life of 74 days
- Cobalt-60 (Co-60) – with a half-life of 53 years
When radioactive medicine or materials come in contact with the patients’ bodies certain body parts and fluids can in fact become radioactive. This can happen during procedures when iridium pellets are used to destroy prostate tumors, or when iodine is used to treat a diseased thyroid gland. As such, even the patients’ urine and feces can become radioactive medical waste.
In most hospitals, there is a method called “radioimmunoassay” with the purpose of establishing whether or not the patient’s body contains radioactive substances. This is done by injecting radioactive antigens into the bloodstream of the patient.
If this all sounds a little harrowing to you, we do have good news: many types of radioactive medical waste have a very short half-life due to the nature of the radioactive materials they have come in contact with. This is why doctors choose to work with fast-decaying isotopes whenever possible, as doing so can avoid harmful side effects to healthy tissue coming from residual radiation.
This also means that these kinds of radioactive medical wastes don’t stay radioactive for very long, which greatly reduces the risks associated with storage and disposal. Still, even if the radiation levels of biomedical waste are gone, it doesn’t necessarily mean that it cannot be considered hazardous or infectious, so you should still proceed with caution, as always. Also, due to the nature of radioactive material, each and every case involving potentially radioactive medical waste has to be evaluated separately, as certain materials have much longer half-lives (as shown in the list of examples above).
In most cases, there are two main sources of radioactive medical waste in hospitals: in waste management, they are referred to as “open” and “sealed” sources. Sealed sources usually mean that they arrive directly from the manufacturer in sealed radioactive containers. Depending on the agreement between the hospital and the manufacturer, these can be sent back after use. Open sources, however, are another story: this the radioactive medical waste that hospital generates in its day-to-day procedures.
Radioactive medical waste management – storage and segregation
Radioactive medical waste should definitely be segregated from other types of medical waste to avoid cross-contamination and be stored in containers equipped with lead shielding to prevent the dispersion of radiation. All this away from areas that people and animals could frequent. The containers should also clearly be labeled with the universal “radioactive symbol”, the type of radioisotope inside, as well as the date of the generation of the waste, so the duration of its half-life can be followed more easily.
If you’re at a loss as to what storage are to choose, good ventilation and easy access are perfectly good attributes to look for when trying to store radioactive medical waste. Since hospitals aren’t exactly nuclear facilities, the waste they produce is almost certainly classified as LLRW (Low-Level Radioactive Waste).
So what is the best way to tackle radioactive medical waste disposal?
As opposed to infectious and hazardous medical waste, where you try and handle the disposal as soon as possible, you will definitely have to keep your radioactive medical waste on-site for a while until its radiation level drops. As we mentioned before, since most isotopes used in medical environments tend to fall in the “short-lived” category, this storage phase usually doesn’t take more than 3 months. Once the half-life (the period during which the material in question is considered radioactive) of the radioactive medical waste is over, it is selected for disposal. Remember, if the container isn’t full, and you add new waste to it, you always have to start the “countdown” again, until the half-life of the newly added waste is over!
The thing about radioactive medical waste, is you can’t really do anything to it to make it “not radioactive”. If you want the radiation level to drop, you’re going to have to wait: there’s no way around that!