The most common ionising radiations used in medicine (diagnostic radiology) are X, gamma, beta rays and electrons. 
Those ionising radiation provide many benefits but also may cause potential harm. The following article will describe you with information on diagnostic radiology, nuclear medicine and radiation therapy. This could be useful for medical practitioner who operate medical x-ray equipment or radiation sources.
The format of the article is in a question and answer to describe sections such as the benefit and risks of ionising radiation to human health, quantify the amount of radiation, mechanism of radiation-induced biological effects, classification of radiation’s effect, magnitude of the risk for cancer and hereditary effects, typical doses of various diagnostic radiology, ways to reduce the risks to very low levels while obtaining benefit still, diagnostic radiological investigations should be avoided, special consideration in diagnostic procedures, and minimising the risk during conduct of radiation therapy.
Also there are table that describe you with deterministic effects after whole-body and localised irradiation by X and gamma rays, typical effective doses from diagnostic medical exposures, graphics of general dose-response relationship for radiation induced deterministic (cell killing) effects and general dose-response relationship for cancer incidence after gamma-ray irradiation (click the picture).
Follow completely Limiting Possible Harm of Ionising Radiations in Diagnostic Radiology in this Medical Practitioner Article, 17 pages/141 Kb of PDF format type (source: icrp.org)
