AS/NZS 4173:1994

1 - AS/NZS 4173:1994 GUIDE TO THE SAFE USE OF LASERS IN HEALTH CARE
4 - PREFACE
5 - CONTENTS
8 - FOREWORD
9 - SECTION 1 - SCOPE AND GENERAL
9 - 1.1 SCOPE
9 - 1.2 APPLICATION
9 - 1.3 REFERENCED DOCUMENTS
9 - 1.4 DEFINITIONS
9 - 1.4.1 Absorption
10 - 1.4.2 Accessible emission limit (AEL)
10 - 1.4.3 Accessible radiation
10 - 1.4.4 Administrative control
10 - 1.4.5 Aiming beam
10 - 1.4.6 Aperture
10 - 1.4.7 Articulated arm delivery system
10 - 1.4.8 Attenuate
10 - 1.4.9 Average power
10 - 1.4.10 Aversion response
10 - 1.4.11 Class of laser
10 - 1.4.12 Coherent
10 - 1.4.13 Collimated
10 - 1.4.14 Continuous wave (CW)
10 - 1.4.15 Convergence
10 - 1.4.16 Cornea
10 - 1.4.17 Corneal hazard
10 - 1.4.18 Delivery system
10 - 1.4.19 Diffraction
10 - 1.4.20 Distal
10 - 1.4.21 Divergence
11 - 1.4.22 Electromagnetic radiation
11 - 1.4.23 Enclosed laser
11 - 1.4.24 Energy (Q)
11 - 1.4.25 Exposure time
11 - 1.4.26 Eye protection
11 - 1.4.27 Fail safe interlock
11 - 1.4.28 Fibre optic delivery system
11 - 1.4.29 Focal length
11 - 1.4.30 Focal point
11 - 1.4.31 Hertz (Hz)
11 - 1.4.32 Infra-red radiation
11 - 1.4.33 Ionizing radiation
11 - 1.4.34 Irradiance
11 - 1.4.35 Lambertian surface
11 - 1.4.36 Laser
11 - 1.4.37 Laser classification
11 - 1.4.38 Laser checklist
11 - 1.4.39 Laser controlled area
12 - 1.4.40 Laser delivery system
12 - 1.4.41 Laser emission indicator
12 - 1.4.42 Laser incident
12 - 1.4.43 Laser safety committee (LSC)
12 - 1.4.44 Laser safety officer (LSO)
12 - 1.4.45 Laser training
12 - 1.4.46 Laser warning sign
12 - 1.4.47 Limiting exposure duration (Tmax.)
12 - 1.4.48 Maintenance
12 - 1.4.49 Maximum permissible exposure (MPE)
12 - 1.4.50 Medical laser product
12 - 1.4.51 Monochromatic
12 - 1.4.52 Micrometer (mm)
12 - 1.4.53 Nanometre (nm)
12 - 1.4.54 Nanosecond (ns)
12 - 1.4.55 Non-ionizing radiation
12 - 1.4.56 Nominal hazard area (NHA)
12 - 1.4.57 Nominal ocular hazard area (NOHA)
13 - 1.4.58 Nominal ocular hazard distance (NOHD)
13 - 1.4.59 Operation
13 - 1.4.60 Optical density
13 - 1.4.61 Peak power
13 - 1.4.62 Power (P)
13 - 1.4.63 Power density
13 - 1.4.64 Power meter
13 - 1.4.65 Proximal
13 - 1.4.66 Pulse mode
13 - 1.4.67 Radian (rad)
13 - 1.4.68 Radiant flux (D)
13 - 1.4.69 Radiant intensity (I)
13 - 1.4.70 Radiant power
13 - 1.4.71 Reflection
13 - 1.4.72 Refraction
13 - 1.4.73 Retina
13 - 1.4.74 Retinal hazard
13 - 1.4.75 Service
13 - 1.4.76 ‘Shall’ and ‘should’
13 - 1.4.77 Shutter
14 - 1.4.78 Smoke evacuator
14 - 1.4.79 Solid angle (X)
14 - 1.4.80 Specular reflection
14 - 1.4.81 Steradian (sr)
14 - 1.4.82 Super pulse
14 - 1.4.83 Transmission
14 - 1.4.84 Ultraviolet radiation
14 - 1.4.85 Visible radiation
14 - 1.4.86 Watt (W)
14 - 1.4.87 Warning sign
14 - 1.4.88 Wavelength (m)
15 - SECTION 2 - THE LASER AND ITS PROPERTIES
15 - 2.1 INTRODUCTION
15 - 2.2 WHAT IS A LASER?
15 - 2.2.1 The laser medium
15 - 2.2.2 The energy source
15 - 2. 2.3 The laser mirrors
15 - 2.2.4 Medical laser safety requirements
15 - 2.3 MODES OF OPERATION
15 - 2.3.1 Continuous wave (CW)
15 - 2.3.2 Pulsed mode
17 - 2.4 PROPERTIES OF LASERS
17 - 2.4.1 Monochromaticity
17 - 2.4.2 Low divergence
17 - 2.5 DESCRIPTION OF THE LASER BEAM
22 - SECTION 3 - LASER DELIVERY SYSTEMS
22 - 3.1 GENERAL
22 - 3.2 DIRECT DELIVERY
22 - 3.3 ARTICULATED ARM
22 - 3.3.1 Limitations of an articulated arm
23 - 3.4 HOLLOW FLEXIBLE WAVEGUIDE
23 - 3.5 FIBRE OPTIC
24 - 3.5.1 Limitations of fibre delivery systems
24 - 3.5.2 Risk to endoscope
25 - 3.6 HANDPIECES AND APPLICATORS
25 - 3.6.1 Applicators with focusing lenses
25 - 3.6.2 Limitations of lens systems
26 - 3.6.3 Sapphire or similar contact tips
26 - 3.6.4 Shaped fibres
26 - 3.6.5 Metallic or ceramic tips
26 - 3.6.6 Diffusers and photodynamic therapy probes
26 - 3.6.7 Micromanipulators
28 - SECTION 4 - BIOLOGICAL EFFECTS
28 - 4.1 LASER INTERACTIONS WITH TISSUE
28 - 4.1.1 General
28 - 4.1.2 Optical interactions
28 - 4.2 THERMAL
29 - 4.2.1 Thermal effects
30 - 4.3 PHOTOABLATIVE
30 - 4.4 ELECTROMECHANICAL (OR PHOTOMECHANICAL)
31 - 4.5 PHOTOCHEMICAL
31 - 4.6 BIOSTIMULATION
32 - SECTION 5 - HAZARDS
32 - 5.1 INTRODUCTION
32 - 5.2 ORGANS AT RISK
32 - 5.2.1 The eyes
32 - 5.2.2 The skin
34 - 5.3 PULSED LASERS
34 - 5.4 OPTICAL FIBRE BREAKAGES
35 - 5.5 FIRE
35 - 5.6 EXPLOSION
35 - 5.7 ELECTROCUTION
35 - 5.8 AIRBORNE CONTAMINANTS
35 - 5.9 DYE LASERS
35 - 5.10 FUMES AND VAPOURS
35 - 5.11 EQUIPMENT EXPLOSION
35 - 5.12 UNSHIELDED LASER FLASH LAMPS/OPTICAL CAVITY
36 - 5.13 HEATED SURFACES OR INSTRUMENTS
36 - 5.14 REFLECTIONS
38 - SECTION 6 - EQUIPMENT
38 - 6.1 CLASSIFICATION OF LASER PRODUCTS
38 - 6.1.1 Labelling requirements
38 - 6.2 LASER EQUIPMENT SAFETY FEATURES
40 - 6.3 OPTICAL GUIDES
41 - SECTION 7 - ADMINISTRATION
41 - 7.1 RESPONSIBILITY
41 - 7.2 ADMINISTRATION
41 - 7.3 LASER SAFETY COMMITTEE
42 - 7.4 LASER SAFETY OFFICER
42 - 7.5 TRAINING
43 - 7.6 MEDICAL SURVEILLANCE
43 - 7.7 OPERATOR APPROVAL
44 - 7.8 STANDARD OPERATING PROCEDURES AND CHECKLISTS
44 - 7.9 LASER INCIDENTS
44 - 7.10 INCIDENT REPORTING
44 - 7.10.1 Incident report
44 - 7.10.2 Equipment malfunction and personnel injury
45 - SECTION 8 - ACCEPTANCE, QUALITY ASSURANCE TESTING AND PREVENTIVE MAINTENANCE
45 - 8.1 GENERAL
45 - 8.2 ACCEPTANCE INSPECTION AND TESTING
45 - 8.3 QUALITY ASSURANCE (QA) TESTS
45 - 8.3.1 General
45 - 8.3.2 Cables
45 - 8.3.3 Emergency switches
45 - 8.3.4 Interlocks
45 - 8.3.5 Indicators
45 - 8.3.6 Beam power
46 - 8.3.7 Articulated arm
46 - 8.3.8 Beam coincidence
46 - 8.3.9 Optical fibres
46 - 8.3.10 Aiming beam
46 - 8.3.11 Delivery power calibration
46 - 8.3.12 Summary of tests
46 - 8.4 OPTICAL FIBRE CLEANING
48 - 8.5 PREVENTIVE MAINTENANCE
49 - SECTION 9 - SAFE PRACTICES
49 - 9.1 GENERAL
49 - 9.2 ESSENTIAL SAFETY REQUIREMENTS
50 - 9.3 USER PRACTICES
51 - 9.4 REMOVAL OF AIRBORNE CONTAMINANTS
52 - 9.5 REDUCTION OF EXPLOSIVE HAZARD
52 - 9.6 NOXIOUS MATERIALS
52 - 9.6.1 General
52 - 9.6.2 Dye lasers
52 - 9.7 USER PRACTICES DURING SPECIALIST CLINICAL APPLICATIONS
52 - 9.8 EYE PROTECTION
52 - 9.8.1 General
53 - 9.8.2 Eye protection with endoscopes
53 - 9.8.3 Factors in determining appropriate eyewear
53 - 9.9 PROTECTIVE CLOTHING
54 - 9.10 AIMING BEAMS AND TARGET INDICATORS
54 - 9.10.1 Alignment and focusing
54 - 9.10.2 Beam quality and target indicator alignment
54 - 9.10.3 Viewing aids
54 - 9.11 FIRE PRECAUTIONS
55 - 9.12 OPTICAL FIBRE SYSTEMS
55 - 9.13 LASER ENVIRONMENT
55 - 9.14 LASERS IN THE OPERATING ROOM
56 - 9.15 OPERATING THEATRES - INSTALLATION REQUIREMENTS FOR CLASS 3B AND 4 MEDICAL LASERS
56 - 9.16 DENTAL SURGERIES
56 - 9.17 OPHTHALMIC PRACTICE
64 - APPENDIX A - SAFE PRACTICES DURING SPECIALIST PROCEDURES
64 - A1 SCOPE
64 - A2 ANAESTHETICS
64 - A2.1 General
64 - A2.2 Inspired oxygen concentrations
64 - A2.3 Fire hazards
64 - A2.4 Endotracheal tubes
64 - A2.5 Methane explosions
64 - A2.6 Movement of surgical field
64 - A2.7 Electrical interference
65 - A2.8 Reflections
65 - A2.9 Pyrolysis of anaesthetic agents
65 - A2.10 Eye protection
65 - A3 PERIPHERAL VASCULAR LASER ANGIOPLASTY
65 - A3.1 General
65 - A3.2 Perforation
65 - A3.3 Eye protection
65 - A3.4 Risk to endoscope
65 - A4 GASTROENTEROLOGY
65 - A4.1 General
65 - A4.2 Types of laser
66 - A4.3 Power density
66 - A4.4 Coaxial gas
66 - A4.5 Eye protection
66 - A4.6 Risk to endoscope
66 - A4.7 Fibre cleaning
66 - A5 DERMATOLOGY
66 - A5.1 General
66 - A5.2 Diagnosis
66 - A5.3 Test treatments
66 - A5.4 Eyelids
66 - A5.5 Eye protection
66 - A6 GYNAECOLOGY
66 - A6.1 General
67 - A6.2 Beam coincidence
67 - A6.3 Articulated arms
67 - A6.4 Laparoscopic procedures
67 - A6.5 Reflections
67 - A6.6 Smoke plume
67 - A6.7 Repetitively pulsed lasers
67 - A6.8 Eye protection
67 - A7 OPHTHALMOLOGY
67 - A7.1 General
67 - A7.2 Contact lenses
68 - A7.3 Aiming beam reflections
68 - A7.4 Safety eyewear
68 - A8 NEUROSURGERY
68 - A8.1 General
68 - A8.2 Aiming beam
68 - A8.3 Fire precautions
68 - A8.4 Foot pedals
68 - A8.5 Smoke plume
68 - A8.6 Anaesthesia
68 - A8.7 Target movement
68 - A8.8 Eye protection
69 - A9 OTOLARYNGOLOGY AND RESPIRATORY TRACT
69 - A9.1 General
69 - A9.2 Endotracheal tubes
69 - A9.3 Fire precautions
69 - A9.4 Eye protection
69 - A9.5 Bronchial procedures
69 - A9.6 Smoke plume
69 - A9.7 Anaesthesia
69 - A10 DENTISTRY
69 - A10.1 General
70 - A10.2 Design of lasers for use in dentistry
70 - A10.3 Safe operation
70 - A10.4 Eye protection
71 - A10.5 Anaesthetic (endotracheal) tubes
71 - A10.6 Education and user training
71 - A11 LOW POWER THERAPEUTIC LASERS
71 - A11.1 General
71 - A11.2 Hazards
72 - APPENDIX B - DESCRIPTION OF LIGHT
72 - B1 DESCRIPTION OF LIGHT
72 - B2 PROPERTIES OF LIGHT
74 - APPENDIX C - GENERATION OF LASER RADIATION
74 - C1 GENERATION OF LASER RADIATION
74 - C2 SPONTANEOUS EMISSION
74 - C3 STIMULATED EMISSION
75 - C5 SPECIFICATION OF THE BEAM INTENSITY
77 - APPENDIX D - EXAMPLES OF TYPICAL LASER TRAINING PROGRAMS
77 - D1 SCOPE
77 - D2 CLINICIANS AND SUPPORT STAFF
77 - D3 HEALTH CARE FACILITY LSO
77 - D4 LASER EQUIPMENT SERVICE STAFF
78 - D5 DENTAL PRACTITIONERS AND SUPPORT STAFF
79 - APPENDIX E - SUGGESTED SUBJECT MATTER FOR LASER SAFETY TRAINING PROGRAMS - CLINICIANS AND SUPPORT STAFF
79 - E1 SCOPE
79 - E2 OPERATIONAL CHARACTERISTICS OF LASERS
79 - E3 LASER HAZARDS
79 - E4 PRINCIPLES AND PROCEDURES FOR SAFE LASER USE
80 - E5 LASER-TISSUE INTERACTIONS SPECIFIC TO DENTAL PROCEDURES
80 - E6 THRESHOLDS FOR SAFE LASER USE IN DENTAL PROCEDURES
81 - APPENDIX F - SAMPLE LASER CHECKLIST
81 - F1 SCOPE
83 - APPENDIX G - CONTACT INFORMATION, REPORTING
83 - AUSTRALIA
83 - NEW ZEALAND
84 - APPENDIX H - ADVISORY AUTHORITIES
86 - APPENDIX I - LASER WARNING SIGNS

Provides a guide to the safe use of lasers and laser systems in diagnostic and therapeutic medical and dental procedures. It is intended for application in hospital operating rooms, clinics and private medical and dental practices. The principles of laser production and operation are described and associated hazards for the operator, patient, support staff and maintenance technicians are detailed. Guidelines are given for administrative and engineering controls of potential hazards and for the appropriate training of relevant staff.

This Standard provides a guide to the safe use of lasers and laser systems in diagnostic and therapeutic medical and dental procedures.The Standard explains the procedural and administrative controls necessary for the safety of patients, health care staff, maintenance personnel, and others who may be in the vicinity of the treatment room and in need of protection against inadvertent exposure. Engineering controls which form part of the laser equipment or the installation are also briefly described to provide an understanding of the general principles of protection. However, detailed specification of laser equipment and installation controls are not included in this Standard, such requirements being separately specified in AS 2211/ NZS 5821, Laser safety.The principles of laser operation and the nature of the associated hazards are briefly described. Examples of specific guidelines for the safe use of lasers in a variety of clinical applications are included in Appendix A.

First published as Joint Standard AS/NZS 4173:1994.