|   Patient Advocate (1000+ posts) 
 Joined:  Jan 2013 Posts: 1,294 Likes: 1 |  Grays is a measure used in radiology. There are two version. I am told the old version uses centigray, more common today is just grays. Usually a number like 75 grays is mentioned. 75 grays is also 7500 centigrays. So 200 centigrays is 2 grays. 30 x 2 = 60 grays total.
 The term fraction is used to describe the daily dose you receive.
 
 Since the radiation is mapped across the area and receives different dosages the number is an average, not exact to any given area as it differs.
 
 60 is on the low end of the range for effective killing effect.
 
 Good luck
 
   Don
 Male, 1955
 Great health except C
 Dec '12
 DX: BOT SCC T2N2bMx, Stage 4a, HPV+, multiple nodes
 1 tooth out
 Jan '13
 2nd tooth out
 Tumor Board -induction TPF (3 cycles), seq CRT
 4-6/2013
 CRT 70gr 2x35, weekly carbo150
 ended 5/29,6/4
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