Cobalt-60

In these conditions, the chromium-51 level in the intestinal excretions is high, and this alerts the doctor to apply remedial measures.

cobalt sixty vitamin b twelve is a cobalt compound normally the few milligrams of b twelve in the body are stored in the liver and released to the blood stream as needed in pernicious anemia a potentially fatal but curable disease the b twelve content of the blood falls from the usual level of three hundred to nine hundred micro micrograms per milliliter to zero to one hundred micro micrograms per milliliter the administration of massive doses of b twelve is the only known remedy for this condition if the b twelve is labeled with radioactive cobalt its passage into the blood stream may be observed by several different methods the simplest is to give the b twelve by mouth and after about eight hours study the level of cobalt radioactivity in the blood Cobalt-60 has been used for several years, but recently Cobalt-58 has been found more satisfactory.

It has a half-life of 72 days, while Cobalt-60 has a 5.3 year half-life.

This reduces greatly the amount of radiation to the patient's liver by the retained radioactivity.

Iodine-131 Like chromium-51, iodine is a versatile tracer element.

Finally, examination of his larynx revealed an ulcerated swelling on the right vocal cord.

A biopsy, microscopic examination of a tissue sample, was made, and it was found the swelling was a squamous cell cancer.

Daily radiation treatment using a Cobalt-60 device was started and continued for 31 days.

And then in terms of the Gamma Knife, um, well, it's a, it's a specialist external beam treatment machine.

It's been designed specifically for intracranial, um, stereotactic radiosurgery, so it, it contains 192 Cobalt-60 s- radioactive sources, and these are finely collimated, um, to deliver radiation to a single focus point.

So this, this design enables delivery of a very high dose of radiation at the focal point with steep dose falloff away from the focus.

So within a very short distance, um, we m- we drop down to very low dose and minimize dose to critical surrounding healthy tissues, which is obviously essential for when we're treating within the brain.

Um, so the design of the Gamma Knife helps, um, to minimize body dose to very low levels.

Um, and, and that's through the, the, you know, multiple things, but I suppose there's the fine collimation of the beams, um, the fact that these beams are in a fixed geometry, so none of them can be, uh, the pri- none of the primary beams can be directed into the torso.

Um, and then other factors include the relatively low energy of the, uh, 192 gamma rays, um, that, but the gamma, uh, y- but from the, that are emitted from Cobalt-60, the average energy is gonna be 1.25 MeV compared to traditional, uh, maybe LINAC treatments, uh, for SRS where you perhaps higher, higher at sort of 6 or 10 MV.

Um, so that's gonna minimize secondary scatter.