Table I.

Small animal research irradiation devices and operating parameters.

Device	Radiation source (Energy)	Dose rate	Small animal applications	Comments
Radionuclide irradiator	Cesium-137 gamma (γ) rays (0.662 MeV γ ray) Less common: Cobalt-60 gamma (γ) rays (1.17 and 1.33 MeV γ rays) Both designs use linear, steel-encapsulated radioactive sources. A timer controls the irradiation time.	1 – 5 Gy/min @ defined positions within irradiation chamber. Nominal radioactivity of 2,000 Curies (Ci). Dose rate varies with source-to-sample distance and dose distribution uniformity may vary across the irradiated volume depending on sample size and position in the irradiation chamber.	Whole-body irradiation. Partial-body irradiations using specially-designed collimators. Irradiation of one or more animals possible, depending on size and geometry.	Simple design makes for ease of use. Source moves from the shielded condition to irradiate a chamber with enclosed sample. Designs are horizontal or vertical operation. Irradiation geometry can be customized for required experimental conditions. Dose rate calibration required to determine irradiation times. Radiological security must be insured.
X-Ray Tube	X rays (30 – 320 kV X-rays) Note: Orthovoltage X-ray energy range is 130– 320 kV. A timer controls the irradiation time.	1 – 5 Gy/min at 50 cm from source. Dose rate varies with energy (kV), filtration, source-to-sample distance, and tube (beam) current.	Whole-body irradiation. Partial-body or single-organ irradiations using collimated fields. Irradiation of one or more animals possible, depending on size and geometry.	A variety of beam energies is possible with depths of penetration from 0 – 2 cm. Can be used in single- or opposed-field geometries. Field sizes can be collimated to a specific size. Requires either a shielded enclosure or a shielded room. Dose rate calibration required to determine irradiation times.