Medical Use Harnesses Radioactive Material for Good
April 20, 2011
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The magic pill that cures cancer has not been invented yet. However, a radioactive “pill” is already in use by physicians to destroy certain cancers from the inside out.
Many people fear radiation because it can cause damage to living cells, but modern medicine has learned to harness that characteristic for good use. If the radiation can be focused on the cancer cells, then the healthy cells can be spared.
There’s a device used by oncology departments across the country called a high dose-rate remote (HDR) afterloader. If the cancer meets specific criteria, like certain breast tumors, it may be a candidate to receive the HDR treatment. The device looks like a slimmer, sleeker version of R2D2 of Star Wars fame. Except instead of holding holograms from Princess Leia inside, it safely stores a small radioactive source with shielding around it.
On the day of the procedure, multiple tiny tubes connected to the HDR device, are inserted into the breast tissue where the tumor is located. The physicist programs the HDR device to automatically crank its source from the shielded position inside the HDR device, through the connecting tubes, and finally settling at a precise position inside the tumor. For the few seconds or minutes that it is there, the source irradiates the tumor tissue directly surrounding it, sparing most of the healthy breast tissue that is further away. When its job is complete, the source retracts into the HDR device, where its shield keeps radiation inside, and it is safe to re-enter the treatment room.
The NRC inspector discusses the procedure with the oncology staff. They talk about interlocks and emergency procedures. While malfunctions are rare, the staff is always ready to respond if the source were to be stuck outside the HDR device or fails to retract when required. The inspector verifies that the physicist uses a radiation meter to check that the source returned to its proper place inside the HDR device. Even though the goal of the treatment is to irradiate the tumor with a large amount of radiation, this must be balanced with the need to reduce the radiation that all the other tissues in the body receive. After treatment, the physicist demonstrates to the NRC inspector how the amount of radiation prescribed by the physician matches the amount of radiation actually deposited in the tumor during treatment.
This is only one example of how radioactive materials are used in medicine. There are many others uses in industrial, commercial and academic applications that the NRC inspects to ensure the safety and security of workers and the public.