ANSI Z136.3 - Definitions Flashcards
Define
Ablation
Tissue removal (such as vaporization) by laser action.
Define
Accessible Emission Limit (AEL)
The maximum accessible emission level permitted within a particular laser hazard class.
Define
Accessible Laser Radiation
Laser radiation to which it is possible for the human eye or skin to be exposed in normal usage. This is also described as laser radiation emitted from a laser, including accessible radiant energy and power, that is compared with the AEL to determine its hazard class.
Define
Administrative Control Measure
Control measures incorporating administrative means (e.g., training, safety approvals, LSO designation, and policies and procedures) to mitigate the potential hazards associated with laser use.
Define
Average Power
The total energy imparted during exposure divided by the exposure duration.
Define
Aversion Response
Closure of the eyelid, eye movement, pupillary constriction, or movement of the head to avoid an exposure to a noxious or bright light stimulant.
In this standard, the aversion response to an exposure from a bright, visible, laser source is assumed to limit the exposure of a specific retinal area to 0.25 seconds or less.
Define
Beam Diameter
The distance between diametrically opposed points in that cross-section of a beam where the power or energy is 1/e (0.368) times that of the peak power or energy.
Define
Blink Reflex
The blink reflex is lid closure associated with the involuntary upward movement of the eye triggered by an external event such as an irritation of the cornea or conjunctiva, a bright flash, the rapid approach of an object, an auditory stimulus, or with facial movements. The ocular aversion response may include a blink reflex.
Define
Collateral Radiation
Any electromagnetic radiation, except laser radiation, emitted by a laser system. This does not include laser target interaction radiation.
Define
Collimated Beam
Effectively, a “parallel” beam of light with very low divergence or convergence.
Define
Continuous Wave (CW)
The output of a laser operated in a continuous rather than a pulsed mode.
In this standard, a laser operating with a continuous output for a period ≥ 0.25 seconds is considered a CW laser.
Define
Control Measure
A means to mitigate potential hazards associated with the use of a HCLS.
Control measures can be divided into three groups: engineering, procedural (administrative), and personal protective equipment (PPE).
Define
Deputy Laser Safety Officer (DLSO)
The person authorized and responsible for managing the laser safety program in the absence of the LSO.
Define
Diffraction
Deviation of part of a beam determined by the wave nature of radiation and occurring when the radiation passes the edge of an opaque obstacle.
Define
Diffuse Reflection
Change of the spatial distribution of a beam of radiation when reflected in multiple directions by non-specular reflections from various surfaces or mediums.
Define
Divergence
The increase in the diameter of the laser beam with propagation distances from the exit aperture.
Note - Sometimes referred to as beam spread.
Define
Embedded Laser
A laser with an assigned hazard classification higher than the classification of the laser system in which it is incorporated, where the system’s lower classification is the result of engineering features that limit the accessible emission levels.
Define
Energy
The capacity for doing work.
Energy content is commonly used to characterize the output from pulsed lasers, and is generally expressed in joules (J).
Define
Engineering Control Measure
Control measures designed or incorporated into the laser or laser system (e.g., interlocks, shutters, watch-dog timer circuits) or its application.
Define
Extended Source
A source of radiation that can be resolved by the eye into a geometrical image, in contrast to a point source of radiation that cannot be resolved into a geometrical image.
Define
Failsafe Interlock
An interlock where the failure of a single mechanical or electrical component of the interlock will cause the system to go into, or remain in, a safe mode.
Define
Fire Retardant
A material that does not support combustion without an external source of heat such as a laser.
Define
Focal Length
The distance from the secondary nodal point of a lens to the primary focal point.
In a thin lens, the focal length is the distance between the lens and the focal point.
Define
Focal Point
The point toward which radiation converges or from which radiation diverges or appears to diverge.
Define
Half-Power Point
The value on either the leading or trailing edge of a laser pulse at which the power is one-half of its maximum value.
Define
Healthcare Application
Use of a laser device on a patient (human or animal) by or under the supervision of a licensed practitioner, physician, dentist, or veterinarian, within their scope of practice for diagnostic, preventive, aesthetic, or therapeutic purposes, where bodily structure of function is altered or symptoms are relieved.
These include prescription use of the medical laser device and over-the-counter indications for use.
Define
Healthcare Facility
For the purpose of this standard, any location where a laser is applied for a healthcare application.
Define
Healthcare Laser System (HCLS)
A laser system used in healthcare applications.
The HCLS includes the laser or lasers, a delivery system to direct the output of the laser, a power supply with control and calibration functions, mechanical housing with interlocks, and associated liquids and gases required for the operation of the laser.
Define
Healthcare Personnel (HCP)
An individual directly involved in the use of a laser for healthcare applications.
Define
Hertz (Hz)
The unit which expresses the frequency of a periodic oscillation in cycles or pulses per second.
1 Hz = 1 cycle per second
Define
Infrared Radiation
Electromagnetic radiation with wavelengths that lie within the range of 700 nm to 1000 µm (1 mm).
Define
Installation
The procedure for supplying and connecting electrical power and other utilities to a HCLS.
Define
Intrabeam Viewing
The viewing condition whereby the eye is exposed to all or part of a laser beam.
Define
Ionizing Radiation
Electromagnetic radiation having sufficiently large photon energy to directly ionize atomic or molecular systems within a single quantum event.
Define
Irradiance
Radiant power incident per unit area upon a surface.
The SI unit of irradiance is watts-per-square-meter (W m^-2), or for convenience, watts-per-square-centimeter (W cm^-2)
Note - The terms power density and fluency rate are sometimes used as synonyms for irradiance, although these terms have slightly different technical meanings.
Define
Joule
A unit of energy.
1 joule = 1 watt second
Symbol: J
Define
Label
For the purposes of this standard, a display of written, printed, or graphic matter upon the protective housing of a laser product.