Looking for clarification about what is a "gray"/Gy?

ohaya1001

Hi,

I am new here and have been accompanying a relative (mainly for logistical support for him and his wife since treatment is at a location away from both of our homes) as he is going through radio therapy treatment for angiosarcoma, and I have a question about "What is a gray?".

From searching, I found that:

"Definition One gray is equal to one joule of energy absorbed per kilogram of matter"

but I am unclear about what they mean by "per kilogram of matter".

Is that referring to the weight of the patient?

Or, something else, and if so, what?

Thanks,

Jim

ohaya1001

Hi,

I think that I just found an answer:

"Radiotherapy - typical target treatment fraction might be 3Gy, with a total dose of perhaps 40-50 Gy delivered over a number of days or weeks (known as dose fractions). Note these values are NOT whole body doses, they are carefully collimated doses delivered to a tumour whilst minimising doses to healthy surrounding tissue. "

(I can't seem to link the entire source link but it was from https://ionactive.co.uk).

Arx001

I’m hoping someone will correct or verify me.

Gray and Sievert contain similar amounts of radiation but Gray refers to radiation absorbed by a material and Sievert refers to radiation absorbed by a tissue. The difference is - different types of radiation (in the same amount) would cause different amount of tissue damages.