North Dakota Administrative Code › Title 33.1 - Department of Environmental Quality › Article 33.1-10 - Radiological Health Rules › Chapter 33.1-10-15 - Therapeutic Radiation Machines › Section 33.1-10-15-02 - Definitions

Current through Supplement No. 393, July, 2024
As used in this chapter, the following definitions
				  apply:
1. "Absorbed dose (D)" means
				the mean energy imparted by ionizing radiation to matter. Absorbed dose is
				determined as the quotient of dE by dM, where dE is the mean energy imparted by
				ionizing radiation to matter of mass dM. The SI unit of absorbed dose is joule
				per kilogram and the special name of the unit of absorbed dose is the gray
				(Gy). The previously used special unit of absorbed dose (rad) is being replaced
				by the gray.
2. "Absorbed dose
				rate" means absorbed dose per unit time, for machines with timers, or dose
				monitor unit per unit time for linear accelerators.
3. "Accelerator-produced material" means any
				material made radioactive by exposing it in a particle accelerator.
4. "Accessible surface" means surface of
				equipment or of an equipment part that can be touched by persons without the
				use of a tool.
5. "Activity" means
				the rate of disintegration or transformation or decay of radioactive material.
				The units of activity are the becquerel (Bq) and the curie (Ci).
6. "Added filtration" means any filtration
				which is in addition to the inherent filtration.
7. "Air kerma (K)" means the kinetic energy
				released in air by ionizing radiation. Kerma is determined as the quotient of
				dE by dM, where dE is the sum of the initial kinetic energies of all the
				charged ionizing particles liberated by uncharged ionizing particles in air of
				mass dM. The SI unit of air kerma is joule per kilogram and the special name
				for the unit of kerma is the gray (Gy).
8. "Barrier" (see "protective
				barrier").
9. "Beam axis" means the
				axis of rotation of the beam-limiting device from the source through the
				centers of the x-ray field.
10.
				"Beam-limiting device" means a device which provides a means to restrict the
				dimensions of the useful beam.
11.
				"Beam-monitoring system" means a system designed and installed in the radiation
				head to detect and measure the radiation present in the useful beam.
12. "Beam-scattering foil" means a thin piece
				of material (usually metallic) placed in the beam to scatter a beam of
				electrons in order to provide a more uniform electron distribution in the
				useful beam.
13. "Bent-beam linear
				accelerator" means a linear accelerator geometry in which the accelerated
				electron beam must change direction by passing through a bending
				magnet.
14. "Brachytherapy" means a
				method of radiation therapy in which sealed sources are utilized to deliver a
				radiation dose at a distance of up to a few centimeters, by surface,
				intracavitary, or interstitial application.
15. "Calibration" means the determination of:
a. The response or reading of an instrument
				relative to a series of known radiation values over the range of the
				instrument; or
b. The strength of a
				source of radiation relative to a standard.