OP  Patient Advocate (1000+ posts)
Joined: Mar 2003 Posts: 1,384 Likes: 1 | Hello Fran, The basic unit of radiation absorbed dose is the amount of energy (joules)absorbed per unit mass (kg). This unit, known as the Gray (Gy), has replaced the unit of rad used in the past (100 rads = 1 Gy; 1 rad = 1 cGy).
The amount of radiation absorbed by the tissues is called the radiation dose (or dosage). Before 1985, dose was measured in a unit called a "rad" (radiation absorbed dose). Now the unit is called a gray (abbreviated as Gy). One Gy is equal to 100 rads; one centigray (abbreviated as cGy) is the same as 1 rad.
70Gy or 7000 RAD (7000 cGy)is generally considered to be the "lifetime" dose for head and neck. This may not be exactly true because of advances with IMRT, where retreatment may still be possible.
I think I got that right, Gary might add more or correct me.
Mark, 21 Year survivor, SCC right tonsil, 3 nodes positive, one with extra-capsular spread. I never asked what stage (would have scared me anyway) Right side tonsillectomy, radical neck dissection right side, maximum radiation to both sides, no chemo, no PEG, age 40 when diagnosed.
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