# Roentgen definition

Roentgen means the special unit of exposure. One roentgen (R) equals 2.58 × 10-4 coulombs/kilogram of air (see “Exposure” and 38.4(4)).
Roentgen. (R) means the special unit of exposure. One roentgen equals 2.58 x 10-4 coulombs/kilogram of air.
Roentgen means the special unit of exposure. One roentgen (R) equals 2.58E-4 coulombs per kilogram of air (see "Exposure" and 12VAC5-481-240).

## Examples of Roentgen in a sentence

• One Roentgen is equal to 2.58 x 10-4 Coulomb per kilogram of air.

• For example, a measured entrance exposure of 0.50 Roentgen from a Mo/Mo Target Filter system at 30 kVp with a measured HVL of 0.36-mm aluminum yields an average glandu- lar dose of (0.50 R) × (174 mrad/R) = 87 mrad or 0.87 mGy.*Wu X.

• RULE 41.6(136C)—APPENDIX IRescinded IAB 4/5/00, effective 5/10/00RULE 41.6(136C)—APPENDIX IIGlandular Dose (in mrad) for 1 Roentgen Entrance Exposure4.5-cm Breast Thickness—50% Adipose/50% Glandular Breast Tissue* To convert from entrance exposure in air in Roentgen to mean glandular breast dose in millirads, multi- ply the entrance exposure by the factor shown in the table for the appropriate kVp and beam quality (HVL) combination.

• The exposure rate due to transmission through the primary protective barrier with the attenuation block in the useful beam, combined with radiation from the image intensifier, shall not exceed 2 milliRoentgen (0.516 uC/kg) per hour at 10 centimeters from any accessible surface of the fluoroscopic imaging assembly beyond the plane of the image receptor for each Roentgen per minute of entrance exposure rate.

• A) The system shall be capable of producing a min- imum output of 4.5 mGy air kerma per second (513 milli Roentgen (mR) per second) when operating at 28 kVp in the standard mammography (moly/ moly) mode at any SID where the sys- tem is designed to operate and when measured by a detector with its center located 4.5 cm above the breast support surface with the compression paddle in place between the source and the detec- tor.

## More Definitions of Roentgen

Roentgen or “R” means the special unit of exposure. One roentgen equals 2.58E−4 coulombs per kilogram of air.
Roentgen. (R) means the special unit of EXPOSURE. One roentgen equals 2.58 x 10 to the -4 power coulombs per kilogram of air. See EXPOSURE.
Roentgen means the special unit of exposure. One roentgen (R) equals 2.58E-4 coulomb per kilogram of air (see "Exposure" and 1.1.15).
Roentgen means the amount of gamma or x-rays required to produce ions resulting in a charge of 0.000258 coulombs per kilogram of air under standard conditions.
Roentgen means the special unit of exposure. One roentgen (R) equals 2.58E-4 coulombs per kilogram of air [See "Exposure" and 420-3-26-.03(13)].
Roentgen. (R) means the special unit of exposure and is equal to the quantity of x or gamma radiation which causes ionization in air equal to 258 microcoulomb per kilogram (see “Exposure”).
Roentgen means the special unit of exposure. One roentgen (R) equals 2.58 x 10-4 coulombs per kilogram (C/kg). (See "Exposure" and Section 310.140 of this Part.)