The amount of radiation absorbed by the tissues is called the radiation dosage. Before 1985, dose was measured in a unit called a "rad" (radiation absorbed dose). Now Gray (Gy) is a unit of radiation dose. One Gy is equal to 100 rads; one centigray (cGy) is the same as 1 rad.
In case ofcurative treatment of a solid epithelial tumor radiation dose raging from 50-70 Gy is administered in case of lymphomas 20-40 Gy is given. This dose is given in daily fraction called the fraction schedule. Typically adults receive 1.8-2 Gy per fraction. The typical treatment schedule is 5 days per week (no weekends). These small frequent doses allow healthy cells time to grow back, repairing damage inflicted by the radiation. Daily fractions of radiation are given using an external source or an internal source such as implants.
In case of palliative treatment a single dose of 6-10Gy may be given to painful superficial tumours, to releive pain.