Laser treatment of tattoos and pigmented lesions

Question 1

Q-switched lasers with extremely short pulse durations are best suited for the selective destruction of most pigmented lesions.

Answer 1

T

Question 2

The main chromophores in skin are melanin in pigmented lesions, oxyhaemoglobin in vascular lesions and water in all cells.

Answer 2

T

Question 3

By limiting the pulse duration (ie. the time that the laser is fired into the chromophore), it is possible to contain damage to the selected chromophore.

Answer 3

T

Question 4

If the laser is fired in a time longer than the target’s thermal relaxation time, the generated heat will cause selective damage to the target chromophore.

Answer 4

F Shorter than the target’s thermal relaxation time (the time required for the target to lose 50% of heat)

Question 5

If the laser pulse duration is too short, the heat produced in the chromophore will have time to spread to the surrounding structures, cause non-selective damage that may lead to scarring.

Answer 5

F This is true with pulse durations that are too long.

Question 6

Since melanosomes are quite large, they cool very slowly when heated (ie. they have a longer thermal relaxation time).

Answer 6

F Melanosomes are small, cool very quickly when heated, short thermal relaxation time.

Question 7

The estimated thermal relaxation time of a melanosome is approximately 250-1000 nanoseconds.

Answer 7

T

Question 8

Lasers with very short pulse durations, in the nanosecond domain, are ideally suited to target the small melanosome chromophore.

Answer 8

T

Question 9

Short pulse lasers are called Q-switched (QS) lasers, indicating quality-switched.

Answer 9

T

Question 10

The delivery of an exceptionally high-energy laser pulse within a long time span results in rapid heating of the target melanosome, causing it to explode.

Answer 10

F Short time span.

Question 11

Melanin has a narrow absorption spectrum.

Answer 11

F Broad – UV, visible and near-infrared light.

Question 12

Ideal wavelengths to treat pigmented lesions would be those with greater absorption by melanin than by oxyhaemoglobin.

Answer 12

T

Question 13

Melanin light absorption decreases with decreasing wavelength.

Answer 13

F Decreases with increasing wavelength.

Question 14

Lasers with shorter wavelengths (eg. pulsed-dye, QS KTP and QS ruby) are typically used for lentigines, given that the pigment is superficial.

Answer 14

T

Question 15

Lentigines are successfully treated with various types of laser sources

Answer 15

T

Question 16

QS lasers including the 694nm QS Ruby, 755nm QS alexandrite and the 532nm frequency-doubled Nd:YAG lasers are most commonly used for the treatment of individual lentigines

Answer 16

T

Question 17

Shorter wavelengths are also optimal for the treatment of dermal pigmented lesions or deeper vascular lesions.

Answer 17

F Not optimal.

Question 18

Longer wavelength pigment lasers (eg QS Nd:YAG) are used where the pigment is located in the dermis, such as naevus of Ota and tattoos.

Answer 18

T

Question 19

QS alexandrite lasers, with an intermediate wavelength, may be used for both superficial and deep pigment.

Answer 19

T

Question 20

Longer pulse width ruby, alexandrite and Nd:YAG lasers, predominantly used for hair removal, do not have the same wavelength as the QS versions used in the treatment of pigmented lesions.

Answer 20

F Do have same wavelength.

Question 21

Intense pulsed light is not a suitable option for the treatment of superficial pigmented lesions.

Answer 21

F

Question 22

With intense pulsed light, polychromatic light ranging from 515-1200nm is emitted with filters to cut off light above a predetermined wavelength.

Answer 22

F Below a predetermined wavelength.

Question 23

Ablative lasers can be used to non-selectively eliminate pigment as a secondary event, eg. CO2, Er:YAG, YSGG and the fractional lasers.

Answer 23

T

Question 24

For treating pigmented lesions, higher fluences should be used in the treatment of patients with darker skin types, since the threshold response will likely occur at a higher fluence.

Answer 24

F Lower fluences.

Question 25

Patients with darker skin are at greater risk for post-operative hyper or hypopigmentation.

Answer 25

T

Question 26

It is preferable to use a longer wavelength device in patients with darker skin, since longer wavelengths penetrate more deeply than shorter wavelengths and produce relatively less epidermal damage with the same dermal effect.

Answer 26

T

Question 27

Patients with suntans can be treated with pigment lasers. .

Answer 27

F Shouldn’t be treated

Question 28

QS lasers are not helpful in the treating naevus of Ota

Answer 28

F Are extremely helpful

Question 29

Prolonged scarring can develop in patients who have used isotretinoin at any time in the past.

Answer 29

F Within preceding 6 months.

Question 30

Retinal injury is only a hazard the patient undergoing laser.

Answer 30

F All personnel in the room.

Question 31

Placement of intraocular metal eye shields should be considered when treatment is in the immediate periocular area.

Answer 31

T

Question 32

Reflective surfaces and windows should be covered, no flammable materials should be present, and access to the procedure room should be limited during laser treatment.

Answer 32

T

Question 33

QS lasers do not generally cause tissue or blood spatter.

Answer 33

F Can cause some tissue and blood splatter.

Question 34

The use of alcohol in the cleaning area prior to laser treatment does not pose any safety hazard.

Answer 34

F Alcohol must not be present on the skin at time of laser delivery (risk flash fire).

Question 35

Clearance of 70% of melanocytic lesions is reported in patients treated at least 5 times with the QS ruby laser

Answer 35

T

Question 36

A study of QS Nd:YAG treatment for acquired nevus of Ota-like macules suggests that epidermal cooling may be associated with an increased risk or post-inflammatory hyperpigmentation

Answer 36

T

Question 37

Following irradiation with QS laser light, sublethal laser damage may increase DNA damage leading to an increase in p16 expression

Answer 37

T

Question 38

There are several reported cases of true malignant transformation of benign pigmented lesions following laser treatment

Answer 38

F There has never been a reported case, despite the fact that benign-appearing nevi that recur following laser treatment may show new-found atypia

Question 39

Red-brown tattoo colour contains pigment Iron oxide and is treated with QS Ruby laser

Answer 39

F QS KTP laser

Question 40

For the treatment of large tattoos, lesions containing large amounts of dermal pigment, or when ablative lasers are used, infiltrative local anaesthesia or regional nerve blocks should be used.

Answer 40

T

Question 41

Shorter wavelength lasers are generally well suited for the treatment of dermal lesions as a result of their high absorption by melanin and limited depth of penetration.

Answer 41

F True for epidermal lesions.

Question 42

Longer wavelength lasers penetrate deeper into the skin for dermal lesions but have less melanin absorption.

Answer 42

T

Question 43

Fair-skinned photodamaged patients with both mild vascular and pigmentary changed are best suited for treatment with intense pulsed light devices.

Answer 43

T

Question 44

The most effective lasers for deeper dermal and pigment tattoos are IPL, KTP and QS ruby lasers.

Answer 44

F QS alexandrite and Nd:YAG.

Question 45

With any modality, the degree of lightening is usually directly proportional to the number of treatments performed.

Answer 45

T

Question 46

Laser treatment of melanocytic naevi is completely safe and recommended for those lesions which are cosmetically bothersome.

Answer 46

F Controversial – unclear whether laser has any potential to induce malignant change in naevus cells.

Question 47

Benign appearing naevi that tend to recur following laser treatment may show new-found clinical and histologic atypia, referred to as pseudomelanoma.

Answer 47

T

Question 48

There has never been a report of true malignant transformation of a benign pigmented lesion following laser treatment.

Answer 48

T

Question 49

QS laser treatment is recommended as first-line treatment of melasma or postinflammatory pigmentation.

Answer 49

F Often paradoxically increases dermal melanophages.

Question 50

Repeated fractional photothermolysis utilising the 1550nm laser (Fraxel) has shown some benefit for melasma.

Answer 50

T

Question 51

Dermal drug-induced hyperpigmentation does not generally respond to treatment with QS lasers.

Answer 51

F

Question 52

In amateur tattoos, pigment is typically present in lower concentrations and located in various levels of the dermis.

Answer 52

T

Question 53

In professional tattoos, there is dense pigment implanted at the epidermal-dermal junction.

Answer 53

F Junction of the papillary and reticular dermis.

Question 54

In professional tattoos, the pigments cinnabar and cadmium red and commonly used to produce red colour.

Answer 54

T

Question 55

In professional tattoos, the pigment cadmium sulphate is commonly used to produce green colour.

Answer 55

F Yellow,

Question 56

In professional tattoos, chromium salts are commonly used to produce a yellow colour.

Answer 56

F Green.

Question 57

In professional tattoos, titanium dioxide is commonly used to produce a white colour.

Answer 57

T

Question 58

In professional tattoos, iron oxide is commonly used to produce a dark blue colour.

Answer 58

F Red-brown colour. Dark blue is produced by cobalt salts.

Question 59

All tattoos contain carbon, which adds to the dark hue of tattoos, and is the most responsive part of the pigment to laser treatment.

Answer 59

T

Question 60

Carbon pigment by itself produces a black tattoo colour.

Answer 60

T

Question 61

QS lasers lighten the majority of tattoos, but clearance is related to density, colour, and composition of the tattoo.

Answer 61

T

Question 62

Typically, amateur, dark, uniformly-coloured tattoos do not respond predictably, even after more than ten laser treatments.

Answer 62

F Clear with some reliability after 3-5 treatments.

Question 63

Professional multi-coloured tattoos respond with some reliability to QS lasers.

Answer 63

F Don’t respond predictably, may not clear completely even after > 10 treatments.

Question 64

Tattoos with red, yellow and orange are particularly difficult to completely clear with most tattoo lasers.

Answer 64

T

Question 65

Older tattoos tend to require an increased number of laser treatments for their removal.

Answer 65

F

Question 66

Tattoos on distal extremities tend to be more resistant to laser treatment as a result of decreased lymphatic drainage.

Answer 66

T

Question 67

The possible fate of tattoo ink particles after laser irradiation includes direct fragmentation of ink particles.

Answer 67

T

Question 68

The possible fate of tattoo ink particles after laser irradiation includes release of ink into the extracellular dermal space.

Answer 68

T

Question 69

The possible fate of tattoo ink particles after laser irradiation includes partial elimination of ink in a scale crust.

Answer 69

T

Question 70

The possible fate of tattoo ink particles after laser irradiation includes rephagocytosis of laser-altered residual tattoo ink particles.

Answer 70

T

Question 71

The possible fate of tattoo ink particles after laser irradiation includes increased ink elimination via the lymphatics.

Answer 71

T

Question 72

Red tattoo colour is best treated with any QS laser.

Answer 72

F QS 510nm pulsed-dye/QS KTP

Question 73

Red-brown tattoo colour is best treated with QS KTP laser.

Answer 73

T

Question 74

Yellow tattoo colour is best treated with QS ruby/QS alexandrite laser.

Answer 74

F QS KTP

Question 75

Green tattoo colour is best treated with QS KTP laser.

Answer 75

F QS ruby/QS alexandrite

Question 76

Dark blue tattoo colour is best treated with QS ruby/QS alexandrite/QS Nd:YAG laser.

Answer 76

T

Question 77

Black tattoo colour is best treated with any QS laser.

Answer 77

F QS ruby/QS alexandrite/QS Nd:YAG

Question 78

White tattoo colour is best treated with any QS laser.

Answer 78

T

Question 79

When treating pigmented lesions, QS lasers do not cause an immediate sign at the site of impact.

Answer 79

F Immediate ash-white colour.

Question 80

The cause of ash-white colour at the site of laser impact is due to heat-induced stream cavities in melanosomes, which cause scattering of visible light producing a white colour.

Answer 80

T

Question 81

The ash-white colour at the site of laser impact gradually disappears over 20 hours.

Answer 81

F 20 minutes.

Question 82

The adequate laser exposure does for melanosome damage correlates well with the clinical threshold for immediate skin whitening.

Answer 82

T

Question 83

If clinical ash-white colour is not visible, the laser exposure dose is sufficient.

Answer 83

F Laser dose is not sufficient.

Question 84

Darker skin has a higher threshold for whitening due to a higher epidermal melanin content.

Answer 84

F Lower threshold for whitening.

Question 85

With higher fluences, solid whitening with epidermal disruption and pinpoint bleeding may occur.

Answer 85

T

Question 86

If the fluence is too high, whitening may be imperceptible.

Answer 86

F Fluence too low.

Question 87

At fluences less than threshold, paradoxical hyperpigmentation may occur as a result of melanocyte stimulation.

Answer 87

T

Question 88

Excessive fluences can result in a thermal burn with tissue sloughing, prolonged wound healing, hypo/hyperpigmentation, textural changes and scarring.

Answer 88

T

Question 89

For darker phototypes, higher fluences with a test spot should be employed.

Answer 89

F Lower fluences.

Question 90

Laser treatments for superficial pigment are generally spaced 4-8 weeks apart.

Answer 90

T

Question 91

Laser treatments for tattoos are ideally spaced 4-8 weeks apart.

Answer 91

F 6-12 weeks.

Question 92

For epidermal lesions, Er:YAG carries a higher risk of scarring than treatment with more selective QS lasers.

Answer 92

T

Question 93

For IPL, cooling is vitally important to minimise the risk of significant epidermal injury.

Answer 93

T

Question 94

For IPL, areas should not be treated with more than one pulse.

Answer 94

F Area may be single, double or triple pulsed.

Question 95

Generally, lower fluences are employed for dermal lesions than for epidermal lesions.

Answer 95

F Higher fluences.

Question 96

Uniform whitening is the desired end point after laser treatment with an approximately 10% overlap for dermal lesions.

Answer 96

T

Question 97

Darker phototypes are probably best treated with longer wavelength lasers such as the 1064nm Nd:YAG.

Answer 97

T

Question 98

The clearing of dermal pigment occurs quickly after laser treatment, typically within 2-4 weeks.

Answer 98

F Clearing is slow and gradual – may occur for many months post treatment.

Question 99

Occlusive dressings can be used over tattoos during laser treatment

Answer 99

T

Question 100

Pulses should not be overlapped during laser treatment of tattoos.

Answer 100

F

Question 101

For tattoo removal, treatment with the lowest possible fluence is generally recommended.

Answer 101

F Highest possible fluence.

Question 102

The desired response for laser tattoo removal is immediate, bright tissue whitening.

Answer 102

T

Question 103

For tattoos with darker, dense pigment, lower laser fluences are recommended for initial treatments. As the pigment lightens, higher fluences can be used.

Answer 103

T

Question 104

In darker skinned patients, the 1064nm Nd:YAG laser is recommended for blue or black pigment.

Answer 104

T

Question 105

Tattoo pigment may lighten for several months following treatment.

Answer 105

T

Question 106

Cosmetic tattoos may contain iron oxide or titanium dioxide when can be treated safely with an QS laser.

Answer 106

F Risk of immediate irreversible darkening of the pigment.

Question 107

The use of occlusive dressings should be avoided after laser treatments.

Answer 107

F This can provide some pain relief

Question 108

Some patients may develop an urticarial reaction after laser with oedema and pruritus, which will subside within the hour.

Answer 108

T

Question 109

Areas treated with laser may appear darker and develop crusting in the first 7-10 days after treatment.

Answer 109

T

Question 110

After laser, patients should be instructed to gently clean treated areas daily, apply occlusive emollient ointments to hasten healing, and remove crusts actively.

Answer 110

F Allow crusts to slough on their own.

Question 111

There is no need to avoid sun exposure after laser treatment.

Answer 111

F

Question 112

Patients treated with 532nm KTP or 510nm pulse dye lasers may develop purpura for 7-10 days as a result of the significant absorption of haemoglobin at these wavelengths.

Answer 112

T

Question 113

The post-operative changes tend to be more pronounced after treatment of epidermal lesions versus dermal lesions and tattoos.

Answer 113

F Dermal lesions and tattoos more pronounced.

Question 114

Vesiculation may occur with shorter wavelength QS laser treatment of tattoos, but typically heal without scarring or textural changes

Answer 114

T

Question 115

The development of blistering in the treatment of dermal lesions is typically of a normal expected reaction.

Answer 115

F Indicates the use of excessive fluences.

Question 116

Factors that may increase risk of scarring and permanent hypopigmentation include excessive fluences using small spot sizes.

Answer 116

T

Question 117

Factors that may increase risk of scarring and permanent hypopigmentation include non-overlapping, separate pulses.

Answer 117

F Pulse stacking.

Question 118

Factors that may increase risk of scarring and permanent hypopigmentation include tattoos with ‘double ink’ (ie. two tattoos on top of one another).

Answer 118

T

Question 119

Factors that may increase risk of scarring and permanent hypopigmentation include too frequent treatments.

Answer 119

T

Question 120

Factors that may increase risk of scarring and permanent hypopigmentation include treatment of areas such as the ankle, deltoid and chest.

Answer 120

T These areas are more prone to scarring.

Question 121

IPL devices tend to cause more pronounced postoperative reactions compared with lasers.

Answer 121

F Less pronounced.

Question 122

Pigmented lesions will darken for up to 1 week following IPL.

Answer 122

T

Question 123

Similar to IPL devices, there is also minimal recovery time with fractional thermolysis.

Answer 123

T

Question 124

Treatments for epidermal lesions are typically spaced 4-6 weeks apart

Answer 124

T