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Surgical MCQs > Laser treatment of tattoos and pigmented lesions > Flashcards

Laser treatment of tattoos and pigmented lesions Flashcards

1
Q

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

A

T

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2
Q

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

A

T

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3
Q

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.

A

T

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4
Q

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.

A

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

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5
Q

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.

A

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

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6
Q

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

A

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

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7
Q

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

A

T

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8
Q

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

A

T

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9
Q

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

A

T

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10
Q

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.

A

F Short time span.

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11
Q

Melanin has a narrow absorption spectrum.

A

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

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12
Q

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

A

T

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13
Q

Melanin light absorption decreases with decreasing wavelength.

A

F Decreases with increasing wavelength.

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14
Q

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

A

T

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15
Q

Lentigines are successfully treated with various types of laser sources

A

T

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16
Q

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

A

T

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17
Q

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

A

F Not optimal.

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18
Q

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.

A

T

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19
Q

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

A

T

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20
Q

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.

A

F Do have same wavelength.

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21
Q

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

A

F

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22
Q

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

A

F Below a predetermined wavelength.

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23
Q

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

A

T

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24
Q

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.

A

F Lower fluences.

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25
Q

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

A

T

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26
Q

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.

A

T

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27
Q

Patients with suntans can be treated with pigment lasers. .

A

F Shouldn’t be treated

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28
Q

QS lasers are not helpful in the treating naevus of Ota

A

F Are extremely helpful

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29
Q

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

A

F Within preceding 6 months.

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30
Q

Retinal injury is only a hazard the patient undergoing laser.

A

F All personnel in the room.

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31
Q

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

A

T

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32
Q

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.

A

T

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33
Q

QS lasers do not generally cause tissue or blood spatter.

A

F Can cause some tissue and blood splatter.

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34
Q

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

A

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

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35
Q

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

A

T

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36
Q

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

A

T

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37
Q

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

A

T

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38
Q

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

A

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

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39
Q

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

A

F QS KTP laser

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40
Q

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.

A

T

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41
Q

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.

A

F True for epidermal lesions.

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42
Q

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

A

T

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43
Q

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

A

T

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44
Q

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

A

F QS alexandrite and Nd:YAG.

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45
Q

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

A

T

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46
Q

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

A

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

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47
Q

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

A

T

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48
Q

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

A

T

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49
Q

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

A

F Often paradoxically increases dermal melanophages.

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50
Q

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

A

T

51
Q

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

A

F

52
Q

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

A

T

53
Q

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

A

F Junction of the papillary and reticular dermis.

54
Q

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

A

T

55
Q

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

A

F Yellow,

56
Q

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

A

F Green.

57
Q

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

A

T

58
Q

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

A

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

59
Q

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

A

T

60
Q

Carbon pigment by itself produces a black tattoo colour.

A

T

61
Q

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

A

T

62
Q

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

A

F Clear with some reliability after 3-5 treatments.

63
Q

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

A

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

64
Q

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

A

T

65
Q

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

A

F

66
Q

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

A

T

67
Q

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

A

T

68
Q

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

A

T

69
Q

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

A

T

70
Q

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

A

T

71
Q

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

A

T

72
Q

Red tattoo colour is best treated with any QS laser.

A

F QS 510nm pulsed-dye/QS KTP

73
Q

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

A

T

74
Q

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

A

F QS KTP

75
Q

Green tattoo colour is best treated with QS KTP laser.

A

F QS ruby/QS alexandrite

76
Q

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

A

T

77
Q

Black tattoo colour is best treated with any QS laser.

A

F QS ruby/QS alexandrite/QS Nd:YAG

78
Q

White tattoo colour is best treated with any QS laser.

A

T

79
Q

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

A

F Immediate ash-white colour.

80
Q

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.

A

T

81
Q

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

A

F 20 minutes.

82
Q

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

A

T

83
Q

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

A

F Laser dose is not sufficient.

84
Q

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

A

F Lower threshold for whitening.

85
Q

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

A

T

86
Q

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

A

F Fluence too low.

87
Q

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

A

T

88
Q

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

A

T

89
Q

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

A

F Lower fluences.

90
Q

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

A

T

91
Q

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

A

F 6-12 weeks.

92
Q

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

A

T

93
Q

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

A

T

94
Q

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

A

F Area may be single, double or triple pulsed.

95
Q

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

A

F Higher fluences.

96
Q

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

A

T

97
Q

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

A

T

98
Q

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

A

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

99
Q

Occlusive dressings can be used over tattoos during laser treatment

A

T

100
Q

Pulses should not be overlapped during laser treatment of tattoos.

A

F

101
Q

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

A

F Highest possible fluence.

102
Q

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

A

T

103
Q

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

A

T

104
Q

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

A

T

105
Q

Tattoo pigment may lighten for several months following treatment.

A

T

106
Q

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

A

F Risk of immediate irreversible darkening of the pigment.

107
Q

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

A

F This can provide some pain relief

108
Q

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

A

T

109
Q

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

A

T

110
Q

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

A

F Allow crusts to slough on their own.

111
Q

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

A

F

112
Q

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.

A

T

113
Q

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

A

F Dermal lesions and tattoos more pronounced.

114
Q

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

A

T

115
Q

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

A

F Indicates the use of excessive fluences.

116
Q

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

A

T

117
Q

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

A

F Pulse stacking.

118
Q

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

A

T

119
Q

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

A

T

120
Q

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

A

T These areas are more prone to scarring.

121
Q

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

A

F Less pronounced.

122
Q

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

A

T

123
Q

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

A

T

124
Q

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

A

T

Surgical MCQs (44 decks)

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