1) Roentgen : - Unit of radiation exposure
● Defined as amount of x / gamma rays that produce a specific amount of ionization in a unit of air under standard temperature and pressure
● Measured in an air chamber, is 2.58 x 10 -4 c/kg air
2) Gray : - Unit of Kerma ( kinetic energy released in material)
● 1 gray = absorption of 1 joule of energy in one kg of tissue
● Earlier unit – Rad ( radiation absorbed dose)
● 1 gray = 100 rad
3) Seivert : - Unit of Radiation dose equivalent
● Sv = Gray x Quality factor / Relative biological effectiveness
● Earlier Unit – Rem ( radiation equivalent man)
● 1 Sv = 100 rem
● Current radiation protection standards devised by using Sv
● QF – for x / gamma/ beta = 1
neutrons = 10
high energy protons = 10
alpha / multiple charged particles = 20
Inspite of all radiological wisdom available to us on internet, we feel there is dearth of platforms focussing on radiologists preparing for examinations - whether post graduate courses or post PG fellow ships. As radiologists who have taken MD and FRCR exams in the past, we can empathise with a budding radiologist who feels a little lost amidst the sea of non exam oriented radiology education. This site aims to provide the training radiologists with the right set of tools which will help them in an exam setting.
