Understanding Laser Treatment Terminology.
(Click a letter for list of glossary terms)
Absorption
The act of tissue taking up laser energy, causing a reaction within the tissue
Absorption peak
Place on an absorption curve where light absorption by a chromophore in tissue is significant
Acne
A disorder of the skin caused by inflammation of sebaceous glands and hair follicles
Anatomical parts of hair
Follicle, bulb, bulge, vascular, supply (matrix) and hair shaft
Angioma (Cherry, spider)
Capillary hemangiomas. Flat or raised tumor composed of a mass of tiny blood vessels, bright red in color, usually 2-5mm in size
ANSI
American National Standards Institute – voluntary nationally recognized group establishing standards for equipment use. The ANSI Z136.3 standard pertains to the use of medical lasers
Atrophic
A wasting, progressive degeneration and loss of function of any part of the body
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Café-au-Lait
Light tan to light brown macules often apparent at birth, epidermal in depth, ranging from 1cm -20cm in diameter
Chloasma/Melasma
Light to medium brown discoloration of the face commonly associated with pregnancy; called “mask of pregnancy”
Chromophore
A target that absorbs light.
Class of lasers
Broad classification of lasers based on the ability to cause injury, Class I-IV, Class IV devices are the most dangerous / powerful
Coherent
All the waves of the laser beam are lined up in phase with each other in time and space
Collagen
An insoluble fibrous protein that is the chief constituent of the fibrils of connective tissue (as in skin and tendons) and of the organic substance of bones
Congenital nevi
Nevi that are present at birth
Congenital vascular malformation
General term for vascular lesion present at birth, such as Port Wine Stains, hemangiomas, and venous malformations
Corneal Shield
Protective covering that is inserted under the eyelid and placed directly onto the surface of the eye.
Cryogen
A substance used to induce a low temperature in an object
DCD
Dynamic Cooling Device which sprays a cryogen cooling agent on the skin prior to the laser pulse being fired or during a laser procedure
Delivery system
Components used to apply laser energy to a patient, i.e. Articulating arm, fiber, handpiece
Dermatitis
Inflammation of the skin
Dermis
The deeper, thicker layer of skin beneath the epidermis that contains blood vessels, nerves and hair
Distance gauge
A spacer between the handpiece lens and the treatment site, which if placed in contact with the skin, ensures that the beam is the proper focal distance
Edema
Swelling due to collection of fluid in interstitial space
Energy density
The amount of energy contained within a given spot size – see Joules
Epidermis
The outermost thin layer of skin
Epilation
The removal of hair
Erythema
Redness of the skin
Facial Telangiectasia
Dilation of a group of capillaries on the face, also called spider veins
Fiber
A quartz or glass filament used as a delivery system for laser energy
Fitzpatrick skin types
Classification system of skin types based on tanning characteristics and melanin content (Types 1-6). Type 1 being fair skin, easily burned – to type 6 never burn very dark skin
Fluence
The amount of energy delivered to the tissue calculated by Watts x Time divided by the spot size in cm2
Focal length
Distance between the lens and the focal point, or the distance from the lens that provides the proper beam size
Focusing lens
Lens used to focus the laser beam to a specific spot size
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Hair anatomy
Folicle, bulb, bulge, vascular supply, matrix, shaft
Hair growth cycle
The growth phases of hair
Hemangioma
Benign tumor made up of blood vessels
Hirsuitism
Excessive hair growth on cheek, chin, lip or chest; especially in women due to an increase in androgenic production
Hyperpigmentation
Increased pigmentation in tissue or skin
Hypertrophic
Enlargement of an organ or part due to the increased size of the cells composing it.
Hypopigmentation
Decreased pigmentation in tissue or skin
Inflammation/inflammatory response
Tissue reaction to irritation, infection, or injury marked by localized warmth, swelling, redness, and pain
Joule (J /(cm2)
A measurement of energy density within a given spot size
Keloid
A nodular mass of scar tissue that has grown well outside the original boundaries of a scar
Laser
Light Amplification by Stimulated Emission of Radiation
Laser parameters
Characteristics of a laser beam, or the settings used on the laser device, which may include
Lentigines
Small tan to brown epidermal lesions or macules usually arising from sun exposure which increase in number as a person ages.
Medium
Substance that produces laser energy
Melanin
Pigment that is produced by melanocytes in the skin
Melanocytes
Pigment producing cells in the skin
Melanocytic nevi
Medium to dark brown macules which are dermal in depth and tend to occur on the trunk and extremities. Can be from .5cm to several centimeters in diameter, and have a relative higher risk of becoming malignant.
Melanosomes
Melanin containing organs within the melanocytes
Microseconds
10-6 seconds, or .000001 seconds
Milliseconds
10-4 seconds or 1/1000th of a second
Monochromatic
Meaning one color; one specific wavelength of light.
Nanometer
10-9 meters, or .000000001 meters
Nanoseconds
10-9 seconds, or .000000001 seconds
Non-ionizing/ionizing radiation
Non-ionizing forms of radiation include
Optical density
Resistance of a substance to light energy
OSHA
Occupational Safety and Health Administration
Perifollicular edema
Swelling due to collection of fluid in the interstitial space in the area around the depression in the skin from which the hair emerges. Positive sign of proper energy delivered for hair removal
Photo-ablation
The act of removing tissue by vaporization with light
Photo-chemical
Act of light causing or initiating a chemical reaction
Photo-thermal
Action of turning light energy into heat.
Photons/ molecules of light
Light energy given off by an excited atom
Photosensitivity
Increased sensitivity to light
Pigmented Lesions
Congenital or acquired brown to black skin lesions
Poikiloderma of Civatte
Hyperpigmentation and telangiectasias of the sides of the neck and chest associated with chronic sun exposure
Port Wine Stain (PWS)
A pink to purple macular congenital vascular malformation of dermal vessels. Also called nevus flammeus.
Post-inflammatory pigmentation
Area(s) of darkening or increased pigment in a laser treated area after treatment.
Protons, neutrons, electrons
Basic components or building blocks of atoms
Pruritis
Itching
Pseudofolliculitus Barbae (PFB)
Beard bumps or razor bumps
Psoriasis
A common chronic skin disease characterized by varying sized reddish patches with white/silver scaly appearance. Occurs mostly on the elbows, knees, scalp, and trunk.
Pulse duration/length
The length of time a laser pulse lasts, usually in nanoseconds, microseconds, or milliseconds.
Pulse repetition rate
The rate at which a laser fires pulses, usually in pulses per second or Hertz (Hz)
Pulsed dye
Laser that produces light from an organic dye in solution
Pulsed vs. CW lasers
Lasers that generate short bursts or pulses of light vs. lasers that emit a continuous beam of light
Purpura
A purplish or blue/black discoloration of the skin after laser treatment, a bruise.
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Reflection
The act of light bouncing off of a surface after striking it
Resonator
Laser head or laser cavity, or laser tube. The place where the lasing medium is housed and the laser energy is produced
Rhytides
Wrinkles, lines or creases that appear most notably on the face as a person ages. Can increase with sun damage and smoking
Rosacea
Dilation of capillaries in the cheeks, nose, forehead and chin; adult onset acne and blushing or flushing induced by a variety of triggers
Scars
Fibrous tissue formed during the healing of a wound
Scattering
Process in which a light beam is split apart in many different directions after striking a object or tissue
Sclerotherapy
The injection of a chemical into a vein to obliterate the vessel
Sebaceous Hyperplasia
Enlargement of sebaceous glands.
Seborrheic Keratosis
A benign pigmented lesion which is raised, tan, brown or black colored, usually on the face, back and chest of older adults; may have a greasy wart-like appearance
Selective Photothermolysis
Theory on which lasers are designed which states that one chooses a laser wavelength that a target absorbs strongly, while surrounding structures do not, and having an exposure time less than the thermal relaxation time of the target
Selectivity
Absorption by a particular target, without effecting surrounding structures
Skin Rejuvenation
Erasing fine lines and wrinkles through the use of laser or light-based treatments
Spider Hemangioma
Arterial spider. A dilated arteriole of the skin with radiating capillary branches.
Spot size
Usually denotes the size of the treatment beam, can be expressed in circular diameter, or in the case of scanner handpieces, other geometric shapes.
Target
Tissue or substance a laser beam is directed at
Telangiectasia
Dilation of a group of capillaries, also called spider veins
Thermal injury
Damage to tissue from a heat source or photo-thermal reaction
Topical anesthesia
Anesthetic applied to the surface of the skin, usually a cream, liquid, or gel.
Transient / Transitory
Temporary
Transmission
The passage of energy through a medium
TRT
Thermal Relaxation Time – the time a target takes to release ½ the heat it had gained after being heated
Ulceration
A depressed or eroded area in the skin
Vascular Lesions
Vascular tissue exhibiting altoreal pathology.
Venous Lake
A superficial vein-like malformation usually located on the lips or ears. It is soft, compressible, flat or slightly elevated, bluish/red.
Warts
A small horny outgrowth on the skin, usually of viral origin, also called verucca
Wavelength
The distance between two consecutive peaks on a wave of light. Usually measured on micrometers or nanometers. Also determines the color of the light.
Wheal
Round or ridge-like transitory swelling on skin.
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