Centigray

Synonyms

cGY

Definition

Centigray (cGY) is the preferred measurement of absorbed radiation and is equivalent to one-hundredth (10⁻²) of a gray, or 1 rad. The gray measures the deposited energy of radiation. The daily dose of radiation is also referred to as a fraction, since each dose is a percentage of the cumulative prescribed dose. The dose is given in sublethal fractions, which protract the dose to facilitate the occurrence of repair kinetics. Hence, radiation oncologists use fractions to take advantage of the differential recovery rates for normal and neoplastic tissue, thereby permitting repopulation of normal cells and inducing radiosensitivity via increased oxygen to the remaining tumor cells. Fractionated dose radiotherapy enhances the treatment efficacy by targeting the cancer cells while mitigating the damage to healthy tissue. This is determined using a therapeutic ratio, which compares the damage to both cancerous and healthy cells (Potters et al. 2005). Moreover, the...