Louisiana Administrative Code › Title 33 - ENVIRONMENTAL QUALITY › Part XV - Radiation Protection › Chapter 6 - X-Rays in the Healing Arts › Section XV-609 - X-Ray and Electron Therapy Systems with Energies of 1 MeV and Above

Current through Register Vol. 50, No. 6, June 20, 2024
A. LAC
				33:XV.Chapter 9, except LAC 33:XV.911.C and D, shall apply to medical
				facilities using therapy systems with energies of 1 MeV and above.
B. In addition to the definitions provided in
				LAC 33:XV.602, the following definitions shall be applicable to LAC 33:XV.609:
Applicator
- a structure that determines the
				  extent of the treatment field at a given distance from the virtual
				  source.
Beam-Scattering Filter
- a filter used to
				  scatter a beam of electrons.
Central Axis of the Beam
- a line passing
				  through the virtual source and the center of the plane figure formed by the
				  edge of the first beam-limiting device.
Dose Monitor Unit
- a unit response from the
				  dose-monitoring system from which the absorbed dose can be calculated.
Dose-Monitoring System
- a system of devices
				  for the detection, measurement, and display of quantities of radiation.
Existing Equipment
- therapy systems subject
				  to LAC 33:XV.609 that were manufactured on or before January 1, 1985.
Field-Flattening Filter
- a filter used to
				  provide dose uniformity over the area of a useful beam of X-rays at a specified
				  depth.
Field Size
- the dimensions along the major
				  axes of an area in a plane perpendicular to the specified direction of the beam
				  of incident radiation at the normal treatment distance and defined by the
				  intersection of the major axes and the 50 percent isodose line.
Gantry
- that part of the system supporting
				  and allowing possible movements of the radiation head.
Interruption of Irradiation
- the stopping
				  of irradiation with the possibility of continuing irradiation without resetting
				  of operating conditions at the control panel.
Isocenter
- a fixed point in space located
				  at the center of the smallest sphere through which the central axis of the beam
				  passes in all conditions. The sphere is described by the intersection of the
				  axes of rotation of the gantry, the collimator, and the couch.
Moving Beam Therapy
- radiation therapy with
				  relative displacement of the useful beam and the patient during irradiation. It
				  includes arc therapy, skip therapy, and rotational therapy.
New Equipment
- systems subject to LAC
				  33:XV.609 that were manufactured after January 1, 1985.
Nominal Treatment Distance
-
a. for electron irradiation, the nominal
				source-to-surface distance along the central axis of the useful beam as
				specified by the manufacturer for the applicator;
b. for X-ray irradiation, the nominal
				source-to-isocenter distance along the central axis of the useful beam. For
				non-isocentric equipment, this distance shall be that specified by the
				manufacturer.
Radiation Head
- the structure from which
				  the useful beam emerges.
Shadow Tray
- a device attached to the
				  radiation head to support auxiliary beam limiting material.
Stationary Beam Therapy
- radiation therapy
				  without relative displacement of the useful beam and the patient during
				  irradiation.
Target
- that part of a radiation head that
				  by design intercepts a beam of accelerated particles with subsequent emission
				  of other radiation.
Virtual Source
- a point from which
				  radiation appears to originate.