Common Terms | Doses from Radioactive Material Procedures | Doses from Diagnostic Radiology Procedures | Fetal Dose Estimates | Occupational Exposure Limits

COMMON TERMS
EDE
The concept of effective dose equivalent (EDE) was introduced to provide a mechanism for assessing the radiation detriment from partial body irradiations in terms of data derived from whole body irradiations. EDE is expressed in rem and takes into account the quality factor of the radiation, the dose to all the organs that are irradiated and their sensitivity to radiation. The rem has been replaced by the sievert in the SI system of units (1 sv = 100 rem).

RAD
The original unit developed for expressing absorbed dose, which is the amount of energy from any type of ionizing radiation (e.g., alpha, beta, gamma, neutrons, etc.) deposited in any medium (e.g., water, tissue, air). A dose of one rad is equivalent to the absorption of 100 ergs (a small but measurable amount of energy) per gram of absorbing tissue. The rad has been replaced by the gray in the SI system of units (1 gray = 100 rad). www.hps.org

REM (Roentgen Equivalent Man)
A unit in the traditional system of units that measures the effects of ionizing radiation on humans. The rem has been replaced by the Sievert in the SI system of units (1 Sievert = 100 rem). www.hps.org

For diagnostic x-ray exposure, a rem is approximately equivalent to a rad

ALARA
Acronym for "As Low As Reasonably Achievable." It means making every reasonable effort to maintain exposures to ionizing radiation as far below the dose limits as practical. Be consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations. These means are in relation to utilization of nuclear energy and licensed materials in the public interest. www.hps.org

See http://hps.org/publicinformation/radterms/ for additional radiation terms

  RADIATION DOSE ESTIMATES FROM COMMONLY USED RADIOPHARMACEUTICALS
(Taken from the Radiation Internal Dose Information Center, RIDIC, dose estimate tables)    

EFFECTIVE DOSE EQUIVALENTS FOR COMMON DIAGNOSTIC PROCEDURES
  FETAL RADIATION DOSE ESTIMATES FROM COMMONLY USED RADIOPHARMACEUTICALS (Taken from the Radiation Internal Dose Information Center, RIDIC, dose estimate tables)  

FETAL DOSE ESTIMATES FOR COMMON X-RAY EXAMS
Assumes Average Size Adult

* Taken from New York State Department of Health Guide for 400 Speed Film/Screen System.
** Taken from "Handbook of Radiation Doses in Nuclear Medicine and Diagnostic X-Ray", CRC Press, 1980, James G. Kereiakes and Marvin Rosenstein. Assumes Half Value Layer of 3.0 mm. of Al.
*** W. Huda, E.L. Nickeloff and J.M. Boone. "Overview of Patient Dosimetry in Diagnostic Radiology in the USA for the past 50 years", Medical Physics, Vol. 35, No. 12, pp 5713-5728

    OCCUPATIONAL EXPOSURE LIMITS

ALARA I - Notify employee.
ALARA II - Notify employee and investigate cause. Take corrective action.