ANSI Z136.3 - Definitions

Question 1

Define

Ablation

Answer 1

Tissue removal (such as vaporization) by laser action.

Question 2

Define

Accessible Emission Limit (AEL)

Answer 2

The maximum accessible emission level permitted within a particular laser hazard class.

Question 3

Define

Accessible Laser Radiation

Answer 3

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.

Question 4

Define

Administrative Control Measure

Answer 4

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.

Question 5

Define

Average Power

Answer 5

The total energy imparted during exposure divided by the exposure duration.

Question 6

Define

Aversion Response

Answer 6

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.

Question 7

Define

Beam Diameter

Answer 7

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.

Question 8

Define

Blink Reflex

Answer 8

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.

Question 9

Define

Collateral Radiation

Answer 9

Any electromagnetic radiation, except laser radiation, emitted by a laser system. This does not include laser target interaction radiation.

Question 10

Define

Collimated Beam

Answer 10

Effectively, a “parallel” beam of light with very low divergence or convergence.

Question 11

Define

Continuous Wave (CW)

Answer 11

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.

Question 12

Define

Control Measure

Answer 12

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).

Question 13

Define

Deputy Laser Safety Officer (DLSO)

Answer 13

The person authorized and responsible for managing the laser safety program in the absence of the LSO.

Question 14

Define

Diffraction

Answer 14

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.

Question 15

Define

Diffuse Reflection

Answer 15

Change of the spatial distribution of a beam of radiation when reflected in multiple directions by non-specular reflections from various surfaces or mediums.

Question 16

Define

Divergence

Answer 16

The increase in the diameter of the laser beam with propagation distances from the exit aperture.

Note - Sometimes referred to as beam spread.

Question 17

Define

Embedded Laser

Answer 17

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.

Question 18

Define

Energy

Answer 18

The capacity for doing work.

Energy content is commonly used to characterize the output from pulsed lasers, and is generally expressed in joules (J).

Question 19

Define

Engineering Control Measure

Answer 19

Control measures designed or incorporated into the laser or laser system (e.g., interlocks, shutters, watch-dog timer circuits) or its application.

Question 20

Define

Extended Source

Answer 20

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.

Question 21

Define

Failsafe Interlock

Answer 21

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.

Question 22

Define

Fire Retardant

Answer 22

A material that does not support combustion without an external source of heat such as a laser.

Question 23

Define

Focal Length

Answer 23

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.

Question 24

Define

Focal Point

Answer 24

The point toward which radiation converges or from which radiation diverges or appears to diverge.

Question 25

Define Half-Power Point

Answer 25

The value on either the leading or trailing edge of a laser pulse at which the power is one-half of its maximum value.

Question 26

Define Healthcare Application

Answer 26

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.

Question 27

Define Healthcare Facility

Answer 27

For the purpose of this standard, any location where a laser is applied for a healthcare application.

Question 28

Define Healthcare Laser System (HCLS)

Answer 28

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.

Question 29

Define Healthcare Personnel (HCP)

Answer 29

An individual directly involved in the use of a laser for healthcare applications.

Question 30

Define Hertz (Hz)

Answer 30

The unit which expresses the frequency of a periodic oscillation in cycles or pulses per second. 1 Hz = 1 cycle per second

Question 31

Define Infrared Radiation

Answer 31

Electromagnetic radiation with wavelengths that lie within the range of 700 nm to 1000 µm (1 mm).

Question 32

Define Installation

Answer 32

The procedure for supplying and connecting electrical power and other utilities to a HCLS.

Question 33

Define Intrabeam Viewing

Answer 33

The viewing condition whereby the eye is exposed to all or part of a laser beam.

Question 34

Define Ionizing Radiation

Answer 34

Electromagnetic radiation having sufficiently large photon energy to directly ionize atomic or molecular systems within a single quantum event.

Question 35

Define Irradiance

Answer 35

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.

Question 36

Define Joule

Answer 36

A unit of energy. 1 joule = 1 watt second Symbol: J

Question 37

Define Label

Answer 37

For the purposes of this standard, a display of written, printed, or graphic matter upon the protective housing of a laser product.

Question 38

Define Labeling

Answer 38

A term used in two senses in this standard. First, Medical Device Regulations, 21CFR801, use “labeling” to indicate the intended and approved use of the HCLS. Second, a term used to describe the physics label attached to the HCLS equipment.

Question 39

Define Laser

Answer 39

A device that produces an intense, coherent, directional beam of light by stimulating electronic or molecular transitions to lower energy levels. An acronym for Light Amplification by Stimulated Emission of Radiation.

Question 40

Define Laser Generated Airborne Contaminants (LGAC)

Answer 40

Airborne contaminants generated when a laser beam interacts with target materials. The materials may include, but are not limited to, plastics, metals, ceramics, glasses, wood, and tissue. LGAC may be in the form of gases, vapors, organic or inorganic particulates, or aerosols, and often are a complex mixture of substances in all three states.

Question 41

Define Laser Operator

Answer 41

A person who handles the laser equipment and is responsible for setting up the laser prior to use or who operates the console to control the laser parameters under supervision of the user. The laser operator may also be the laser user.

Question 42

Define Laser Protective Eyewear (LPE)

Answer 42

Equipment such as eyecups, face shields, goggles, eye shields, spectacles and visors, intended to protect the eyes from potentially harmful exposure to laser radiation, including blindness. LPE does not include laser protective windows.

Question 43

Define Laser Radiation

Answer 43

Coherent optical (non-ionizing) radiation emitted by a laser.

Question 44

Define Laser Safety Officer (LSO)

Answer 44

The LSO is the person authorized by the administration and is responsible for the laser safety program. This individual has the training and experience to administer a laser safety program and has responsibility for oversight and control of laser hazards (see 1.3).

Question 45

Define Laser Safety Site Contact (LSSC)

Answer 45

In diverse practice areas, such as large facilities or corporations, an LSSC serves under the supervision of the LSO. The LSSC is responsible for all aspects of laser safety in each site where lasers are used and for which that individual has responsibility.

Question 46

Define Laser Safety Specialist (LSS)

Answer 46

The LSSC is referred to as the LSS in some facilities.

Question 47

Define Laser System

Answer 47

An assembly of electrical, mechanical, and optical components that includes a laser.

Question 48

Define Laser Target Interaction (LTIR)

Answer 48

Non-laser radiation, including ionizing radiation, emitted by a material as a result of that material's exposure to laser radiation.

Question 49

Define Laser Treatment Controlled Area (LTCA)

Answer 49

The room within which the HCLS is used, and the occupancy and activity of those within this area are subject to supervision for the purpose of protection against all hazards associated with the use of HCLS. In a large room, a limited LTCA can be designated if clearly marked and controlled.

Question 50

Define Laser User

Answer 50

A person who controls the application of the laser radiation at the working area and is applying the laser energy of the HCLS for its intended purpose within their scope of practice, license, training, and experience.

Question 51

Define Limiting Aperture

Answer 51

The diameter of a circle over which irradiance or radiant exposure is averaged for purposes of hazard evaluation.

Question 52

Define Limiting Exposure Duration

Answer 52

An exposure duration that is specifically limited by the design or intended use(s).

Question 53

Define Maintenance

Answer 53

Performance of those adjustments or procedures specified in user information provided by the manufacturer with the laser or laser system, which are to be performed by the user to ensure the intended performance of the product. Maintenance does not include operation or service as defined in this section.

Question 54

Define Maximum Permissible Exposure (MPE)

Answer 54

The level of laser radiation to which a person, under normal circumstances, may be exposed without hazardous effects or adverse biological changes in the eye or skin. The MPE criteria for the eye and skin are presented in ANSI Z136.1-2014.

Question 55

Define Medical Device Labeling

Answer 55

A term defined in the FDA Medical Device Regulations, 21CFR801, which includes all of the information required to appear in the device labeling including the intended use. Labeling, for example in a user's manual, is required to supply adequate directions for use, which is defined to mean directions under which the layman can use a device safely and for the purposes for which it is intended. Exemptions from adequate directions for use may apply under specific circumstances for prescription devices.

Question 56

Define Nominal Hazard Zone (NHZ)

Answer 56

The space within which the level of the direct, reflected, or scattered radiation during normal operation exceeds the applicable MPE. Note: Also referred to as the nominal ocular hazard area (NOHA)

Question 57

Define Nominal Ocular Hazard Distance (NOHD)

Answer 57

The distance along the axis of the unobstructed beam from the laser to the human eye beyond which the irradiance or radiant exposure during normal operation is not expected to exceed the applicable MPE.

Question 58

Define Non-Beam Hazard

Answer 58

All hazards arising from the operation of a laser system, excluding direct human exposure to direct or scattered laser radiation.

Question 59

Define Operation

Answer 59

The performance of the laser or laser system over the full range of its intended functions (normal operation). It does not include maintenance or service as defined in this section.

Question 60

Define Optical Density D(λ), OD

Answer 60

A value that defines the attenuation property of a filter and is equal to the logarithm to the base ten of the reciprocal of the transmittance at a particular wavelength. D(λ) = log(1/τ(λ)) τ(λ)=transmittance at wavelength λ

Question 61

Define Patient

Answer 61

For purposes of this standard a patient is the recipient of the laser health care application.

Question 62

Define Perioperative

Answer 62

The period of time that extends from the setup to the completion of a surgical procedure, including the setup, testing, and use of the healthcare laser system.

Question 63

Define Personnel

Answer 63

Those persons who are engaged in laser use for healthcare applications.

Question 64

Define Personal Protective Equipment (PPE)

Answer 64

Personal safety protective devices used to mitigate hazards associated with laser use (e.g., laser eye protection, laser protective eyewear), and biological hazards for infection control (e.g., protective gowns, clothing, masks, and gloves).

Question 65

Define Plasma Radiation

Answer 65

Black-body radiation generated by luminescence of matter in a laser generated plume.

Question 66

Define Plume

Answer 66

Gases, vapors, and aerosol created by vaporization of tissue or other materials, which may contain viable bacteria, viruses, cellular debris, or noxious fumes.

Question 67

Define Point Source

Answer 67

For purposes of this standard, a source with an angular subtense at the cornea equal to or less than alpha-min (α-min), ≤ 1.5 mrad

Question 68

Define Policies and Procedures (P&Ps)

Answer 68

Written policies and procedures that list administrative and procedural control safety measures.

Question 69

Define Power

Answer 69

The rate at which energy is emitted, transferred, or received. Power is expressed in watts (W). 1 W = 1 Joule per second Symbol: W

Question 70

Define Pulse Repetition Frequency (PRF)

Answer 70

The number of pulses occurring per second, expressed in hertz Symbol: F

Question 71

Define Procedural Control Measure

Answer 71

Methods or instructions that specify rules, work practices, or both. Procedural control measures, which implement or supplement engineering controls, may specify the use of personal protectiv equipment (PPE). Conflate: Administrative and procedural control measures. Thereby ensures immediate access to both and conformity in their representation.

Question 72

Define Protective Housing

Answer 72

An enclosure that surrounds a laser or laser system and prevents access to laser radiation above the applicable MPE. The aperture through which the useful beam is emitted is not part of the protective housing. The protective housing may enclose associated optics and a workstation, and limits access to other associated radiant energy emissions and to electrical hazards associated with components and terminals.

Question 73

Define Pulse Duration

Answer 73

The duration of a laser pulse; usually measured as the time interval between the half-power points on the leading and trailing edges of the pulse.

Question 74

Define Pulsed Laser

Answer 74

A laser that delivers its energy int he form of a single pulse or a train of pulses. In this standard, the duration of a pulse is less than 0.25 seconds.

Question 75

Define Radian (rad)

Answer 75

A unit of angular measure equal to the angle subtended at the center of a circle by an arc whose length is equal to the radius of the circle. 1 radian ≈ 57.3 degrees 2π radians = 360 degrees

Question 76

Define Radiance

Answer 76

Radiant flux or power output per unit solid angle per unit area expressed in units of watts per steradian per meter squared (W sr^-1 m^-2) Symbol: L

Question 77

Define Radiant Energy

Answer 77

Energy emitted, transferred, or received in the form of radiation expressed in the units of joules (J). Symbol: Q

Question 78

Define Radiant Exposure

Answer 78

Surface density of the radiant energy received. The SI unit of radiant exposure is joules per meter squared (J m^-2), or for convenience joules per centimeter squared (J cm^-2). Symbol: H Note: The terms energy density and fluence are sometimes used as synonyms for radiant exposure, although these terms have slightly different technical meanings. The surface density of radiant energy received is synonymous with the radiant energy per unit area incident upon a surface.

Question 79

Define Radiant Flux

Answer 79

Power emitted, transferred, or received in the form of radiation expressed in units of watts (W). Note: Also called radiant power.

Question 80

Define Radiant Intensity (of a source in a given direction)

Answer 80

Quotient of the radiant flux leaving a source and propagated in an element of solid angle containing the given direction, and the element of solid angle expressed in units of watts per steradian (W sr^-1)

Question 81

Define Radiant Power

Answer 81

Power emitted, transferred, or received in the form of radiation.

Question 82

Define Reflectance

Answer 82

The ratio of total reflected radiant power to total incident power. Also called reflectivity.

Question 83

Define Repetitive Pulse Laser

Answer 83

A laser with multiple pulses of radiant energy occurring in a sequence.

Question 84

Define Service

Answer 84

The performance of those procedures or adjustments described in the manufacturer's service instructions that may affect any aspect of the performance of the laser or laser system. These are usually performed by qualified technical personnel provided by the manufacturer or service companies. It does not include maintenance or operation as defined in this section.

Question 85

Define Shall

Answer 85

The word "shall" is to be understood as mandatory.

Question 86

Define Should

Answer 86

The word "should" is to be understood as advisory.

Question 87

Define Specular Reflection

Answer 87

A mirror-like reflection.

Question 88

Define Transmission

Answer 88

Passage of radiation through a medium.

Question 89

Define Transmittance

Answer 89

The ratio of total transmitted radiant power to total incident radiant power. Symbol: τ

Question 90

Define Ultraviolet (UV) Radiation

Answer 90

Electromagnetic radiation with wavelengths shorter than those of visible radiation; for the purpose of this standard wavelengths between 180 nm and 400 nm.

Question 91

Define Visible Radiation (light)

Answer 91

Electromagnetic radiation that can be detected by the human eye. This term is commonly used to describe wavelengths that lie in the range of 400 nm to 700 nm.

Question 92

Define Watt

Answer 92

The unit of power or radiant flux. 1 watt = 1 J per second

Question 93

Define Wavelength

Answer 93

The distance between two successive points on a periodic wave that have the same phase. Symbol: λ