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Surgical MCQs > Energy-based treatment of the ageing face for skin resurfacing – Ablative and non-ablative lasers & Photodynamic therapy > Flashcards

Energy-based treatment of the ageing face for skin resurfacing – Ablative and non-ablative lasers & Photodynamic therapy Flashcards

1
Q

Regarding photodamage, ablative laser skin resurfacing offers the most substantial clinical improvement.

A

T

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2
Q

Regarding photodamage, non-ablative laser resurfacing is associated with several weeks of postoperative recovery.

A

F True for ablative laser skin resurfacing.

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3
Q

Ablative laser skin resurfacing provides a modest improvement of photodamaged skin with a limited post-treatment recovery period.

A

F True for non-ablative laser skin resurfacing.

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4
Q

Fractionated laser systems provide the benefits of higher energy treatments with fewer side effects than traditional lasers.

A

T

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5
Q

Extrinsic ageing effects are usually limited to the epidermis and upper papillary dermis and are therefore amenable to treatment with laser.

A

T

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6
Q

Ablative lasers are selectively absorbed by water and act to vaporise skin in a controlled manner.

A

T

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7
Q

Ablative laser resurfacing carries a reduced risk of scarring and pigmentary alteration compared to non-ablative methods.

A

F Increased risk.

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8
Q

Ablative laser resurfacing can be safely carried out in patients with darker skin types.

A

F Ideally skin type I or II.

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9
Q

Preoperative use of topical tretinoin, hydroquinone or glycolic acid for several weeks reduces the incidence of postablative laser hyperpigmentation.

A

F

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10
Q

Prophylactic antibiotics should be used postablative laser to reduce the possibility of bacterial contamination and overgrowth in the de-epithelialised skin.

A

F Controversial. Studies haven’t shown any significant change in infection rate.

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11
Q

Pts with a history of herpes labialis should receive prophylactic oral antivirals starting 1 day prior to resurfacing and continuing for 10 days postoperatively.

A

T

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12
Q

Ablative resurfacing lasers include: pulsed CO2 (10600nm), pulsed erbium:YAG (2940), and fractionated (10600 and 2940nm)

A

T

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13
Q

Using CO2 laser, water-containing tissue is vaporised to a depth of approximately 20-100um, producing a zone of thermal damage ranging from 20 to 150um.

A

F Vaporisation depth 20-60um.

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14
Q

Using CO2 laser, depth of ablation is directly correlated with number of passes performed and is usually restricted to the epidermis and upper papillary dermis.

A

T

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15
Q

Using CO2 laser, stacking of laser pulses doesn’t cause excessive thermal injury.

A

F Does. Risk of scarring.

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16
Q

Using CO2 laser, an ablative plateau is reached, with less effective tissue ablation and accumulation of thermal injury.

A

T This effect is due to reduced water content after initial dessication.

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17
Q

With any laser system, complete removal of partially dessicated tissue and avoidance of pulse stacking is paramount to prevention of excessive thermal accumulation.

A

T

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18
Q

The objective of ablative laser skin resurfacing is to vaporise tissue to the reticular dermis.

A

F Papillary dermis.

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19
Q

Limiting the depth of ablative laser penetration to the reticular dermis decreases the risk for scarring and permanent pigmentary alteration.

A

F Papillary dermis.

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20
Q

For CO2 laser, whether or not previous treatments have been delivered to an area is irrelevant when choosing treatment parameters.

A

F

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21
Q

Areas with thinner skin require fewer passes with a CO2 laser.

A

T

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22
Q

CO2 laser resurfacing of non-facial areas (eg neck, chest) should be avoided due to the relative paucity of pilosebaceous units in these areas.

A

T

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23
Q

CO2 laser resurfacing can offer at least a 50% improvement over baseline in overall skin tone and wrinkle severity.

A

T

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24
Q

The most profound effects of CO2 laser resurfacing occur in the epidermis.

A

F Papillary dermis – elastotic material replaced with normal collagen bundles.

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25
Q

The advantages of CO2 laser skin resurfacing are the excellent tissue contraction, haemostasis, prolonged neocollagenesis and collagen remodelling.

A

T

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26
Q

Absolute CI to CO2 laser resurfacing includes active infection or an inflammatory skin condition involving the areas to be treated.

A

T

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27
Q

Contraindication to CO2 laser resurfacing includes the use of isotretinoin within the preceding 2 years.

A

F Preceding 6-12 months.

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28
Q

Contraindication to CO2 laser resurfacing includes a history of keloids.

A

T

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29
Q

YAG laser emits a 2940nm wavelength light corresponds to the 3000nm absorption peak of water-

A

T

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30
Q

The absorption coefficient of the Er:YAG laser makes it less efficiently absorbed by water-containing tissue compared with the CO2 laser.

A

F 12-18 times more efficiently absorbed.

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31
Q

The pulse duration for Er:YAG is much shorter than the CO2 laser, resulting in decreased thermal diffusion, less effective haemostasis and increased intraoperative bleeding which hampens deeper dermal treatment.

A

T

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32
Q

The amount of collagen contraction is increased with Er:YAG compared to CO2 laser.

A

F Decreased due to limited skin injury.

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33
Q

Much narrower zones of thermal necrosis are produced with Er:YAG compared to CO2 laser.

A

T

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34
Q

There is no distinctive popping sound with Er:YAG laser use compared to CO2 laser.

A

F Popping sound produced by ejection of dessicated tissue.

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35
Q

With Er:YAG laser, because little tissue necrosis is produced with each pass of the laser, manual removal of dessicated tissue is often unnecessary.

A

T

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36
Q

short-pulsed erbium laser fluences used most often range from 30-50um J/cm2, depending on the degree of photodamage and anatomic location.

A

F 5 to 15 J/cm2.

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37
Q

When lower fluences are used, it is often necessary to perform multiple passes to ablate the entire dermis with Er:YAG laser.

A

T

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38
Q

The depth of ablation with the short-pulsed Er:YAG doesn’t diminish with successive passes.

A

T Because the amount of thermal necrosis is minimal with each pass.

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39
Q

It takes 3-4 times as many passes with the CO2 laser to achieve similar depths of penetration as with one pass of the Er:YAG laser at typical treatment parameters.

A

F Other way around.

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40
Q

Because more pulses must be used with the Er:YAG laser, there is an increased possibility of uneven tissue penetration.

A

T

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41
Q

Areas treated with Er:YAG immediately whiten after treatment and then the white colour quickly fades.

A

T

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42
Q

Short-pulsed Er:YAG can be used for superficial or dermal lesions

A

T

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43
Q

Short-pulsed Er:YAG tends to have a longer recovery period.

A

F Shorter.

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44
Q

Re-epithelialisation post Er:YAG laser is completed within 8.5 days on average, compared with 5.5 days for multiple-pass CO2 laser procedures.

A

F Other way around.

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45
Q

Post-operative pain and duration of erythema are reduced after short-pulsed Er:YAG compared to CO2 laser.

A

T

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46
Q

Post-op erythema from Er:YAG resolves within 1-2 weeks.

A

F 3-4 weeks.

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47
Q

Er:YAG is contraindicated in darker skin phototypes.

A

F

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48
Q

The major disadvantage of short-pulsed Er:YAG is its limited ability to effect significant collagen shrinkage.

A

T

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49
Q

The final result with Er:YAG ablation is typically less impressive compared with CO2 resurfacing for deeper rhytides.

A

T

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50
Q

For mild photodamage, Er:YAG only typically produces improvement of about 20%.

A

F 50%.

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51
Q

Ablative fractional resurfacing devices have the ability to achieve comparable clinical results to non-fractional methods.

A

T

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52
Q

Ablative fractional resurfacing devices can keep the majority of the dermis intact, thus allowing quicker recovery periods and an improved safety profile.

A

F Epidermis.

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53
Q

Fractional lasers deliver energy through macroscopic zones of thermal injury, leading to coagulation necrosis and resultant new collagen formation.

A

F Microscopic.

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54
Q

Annular coagulation of dermal collagen occurs with fractional ablative laser, with increasing fluences resulting in increasing treatment depths.

A

T

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55
Q

With fractional ablative laser, the deep dermal ablated zones are surrounded by zones of sparing, which result in quicker recovery compared to non-fractional methods.

A

T

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56
Q

Using fractional ablative laser, multiple treatments are required for any noticeable clinical improvement.

A

F Improvement in texture, dyschromia and mild laxity after one treatment.

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57
Q

Fraxel is a fractionated CO2 laser.

A

T

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58
Q

With fractional laser, ablation depth and the residual thermal damage depend on energy density and the number of stacked pulses used.

A

T

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59
Q

Fractional and non-fractional laser treatments should never be combined.

A

F

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60
Q

Fractional laser ablation requires longer recovery time than other ablative lasers.

A

F Average 5-7 days.

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61
Q

Temporary bronzing, acneiform eruptions and milia formation can occur after fractional laser ablation.

A

T

62
Q

Results from a single fractional laser ablative treatment are noted 3-6 weeks after the procedure.

A

F 3-6 months, after collagen remodelling complete.

63
Q

Ablative fractional laser resurfacing cannot be performed on the neck and chest.

A

F

64
Q

Scarring and pigmentary alteration are potential side effects of ablative fractional laser.

A

F These have never been reported.

65
Q

Expected side effects of ablative laser resurfacing include erythema, oedema and pruritus.

A

T

66
Q

Mild complications of ablative laser include extended erythema, milia, acne and contact dermatitis.

A

T

67
Q

Severe complications of ablative laser include hypopigmentation, hypertrophic scarring and ectropion.

A

T

68
Q

Erythema after ablative laser is always mild and resolves quickly.

A

F Can be intense and may persist for months.

69
Q

Degree of erythema is unrelated to the depth of ablation and the number of laser passes performed.

A

F Correlates directly with this.

70
Q

Underlying rosacea or dermatitis can aggravate the erythema seen post-laser ablation.

A

T

71
Q

Post-operative erythema resolves spontaneously

A

T May be reduced with the application of topical ascorbic acid

72
Q

Topical ascorbic acid should be avoided post-laser ablation.

A

F Can reduce postoperative erythema.

73
Q

Topical ascorbic acid can be used immediately after laser ablation.

A

F Should wait at least 4 weeks.

74
Q

Topical agents such as retinoids, glycolic acid and fragrance-containing or chemical-containing cosmetics and sunscreens should be strictly avoided in the early postoperative period after ablative laser.

A

T

75
Q

Minor side effects of laser resurfacing include milia formation and acne exacerbation.

A

T

76
Q

Milia and acne seen post ablative laser are thought to be due to occlusive dressing and ointments in the postoperative periods, particularly in patients who are prone to acne.

A

T

77
Q

Reactivation of labial HSV post laser ablation is most likely due to thermal tissue damage and epidermal disruption.

A

T

78
Q

After CO2 resurfacing, approximately 20% of patients develop a localised or disseminated form of HSV.

A

F 7-10%, even with appropriate prophylaxis

79
Q

Infections of HSV occurring as a complication of laser resurfacing tend to develop within the first postoperative week.

A

T

80
Q

For HSV prophylaxis in the setting of ablative laser, patients should begin prophylaxis 1 week prior to surgery and continue for 1 week postoperatively.

A

F Begin by day of surgery, continue 7-10 days postop.

81
Q

Ectropion of the lower eyelid is more likely to occur post ablative laser in patients who have had previous blepharoplasty or other surgery of the periorbital area.

A

T

82
Q

The snap test should be performed on the lower eyelid prior to ablative laser – laser resurfacing should be avoided if the skin does not return briskly to its normal resting position.

A

T

83
Q

There is no indication for altering fluence of laser passes when treating the periorbital area.

A

F Use lower fluence and fewer passes to reduce risk of lid eversion.

84
Q

Postoperative hypopigmentation is often not seen for several months after ablative laser.

A

T

85
Q

There is a lower risk of infection associated with the use of ‘closed’ dressing techniques post ablative laser.

A

F Higher risk reported.

86
Q

Pale skin tones have a lower incidence of undesirable postoperative hyperpigmentation after ablative laser.

A

T

87
Q

There are no risks associated with ablative skin resurfacing in scleroderma, LE or vitiligo.

A

F These conditions can worsen.

88
Q

Koebnerisation of psoriasis, verrucae and molluscum can occur after ablative skin resurfacing.

A

T

89
Q

Concomitant isotretinoin use could potentially lead to increased risk of postoperative hypertrophic scar formation.

A

T Due to effects on wound healing and collagenesis.

90
Q

Treatment with laser skin resurfacing should be delayed for at least 1-2 years after cessation of isotretinoin.

A

F 6-12 months

91
Q

There is a greater risk of scar formation after laser resurfacing, independent of the laser’s selectivity and the operator’s expertise.

A

T

92
Q

Complete control of acne should be obtained prior to ablative laser skin resurfacing.

A

T

93
Q

patients with mild to moderate facial photodamage with realistic treatment expectations are the best candidates for non-ablative procedures.

A

T

94
Q

There is no need to avoid sun exposure prior to non-ablative laser procedures.

A

F Should be avoided, esp with PDL or IPL (shorter wavelength systems).

95
Q

Non-ablative laser systems stimulate collagen production and dermal remodelling without wounding the epidermis.

A

T

96
Q

Non-ablative lasers include mid-infrared lasers, visible light lasers and IPL systems.

A

T

97
Q

Devices which emit light within the infrared portion of the electromagnetic spectrum (1000-1500nm) are weakly absorbed by superficial water-containing tissue, thereby they don’t penetrate deep tissue.

A

F Deeper tissue penetration is affected.

98
Q

Contact cooling hand pieces or dynamic cryogen devices are used for all ablative laser systems.

A

F Non-ablative laser systems.

99
Q

Treatment of facial photodamage with non-ablative technology does not produce results comparable to those of ablative carbon lasers.

A

T

100
Q

The long pulsed Nd:YAG 1320nm wavelength laser is associated with a high scattering coefficient that allows for dispersion of laser irradiation throughout the dermis.

A

T

101
Q

The long pulsed Nd:YAG 1320nm wavelength hand piece contains two portals: the laser beam itself, and a dynamic cryogen spray apparatus used for epidermal cooling.

A

F 3rd portal – thermal feedback sensor.

102
Q

Using the Nd:YAG laser, epidermal temperatures must be kept lower than 50deg C in order to prevent unwanted sequelae from excessive heat production.

A

T

103
Q

Only one treatment session with the Nd:YAG laser is usually needed for maximum mitigation of fine rhytides.

A

F Usually three or more typically once a month.

104
Q

Side effects of Nd:YAG long pulsed laser are generally mild and include transient oedema and erythema.

A

T

105
Q

The long-pulsed Diode laser has a wavelength of 1540nm.

A

F 1450nm.

106
Q

The diode laser targets dermal water and penetrates skin to an approximate depth of 100nm.

A

F 500nm.

107
Q

For non-ablative lasers, the perioribtal area is usually more responsive to laser treatments than the perioral area.

A

T

108
Q

The Erbium:glass laser has a wavelength of 1450nm.

A

F 1540nm.

109
Q

The erbium:glass laser has the least amount of melanin absorbed compared with the long-pulsed Nd:YAG and diode laser systems.

A

T

110
Q

Pulsed-dye lasers used for ablation have a wavelength of 585nm and 595nm.

A

T

111
Q

The most common side effects of PDL treatment include mild oedema, purpura, and permanent post-inflammatory hyperpigmentation.

A

F Transient post-inflammatory hyperpigmentation.

112
Q

IPL emits a broad continuous spectrum of light in the range of 515-1200nm.

A

T

113
Q

For IPL, cut-off filters are used to eliminate shorter wavelengths depending on the clinical application, with shorter filters favouring heating of melanin and haemoglobin.

A

T

114
Q

IPL can improve wrinkling, skin coarseness, irregular pigmentation, pore size and telangiectasia.

A

T

115
Q

Ablative fractional lasers produce microscopic treatment zones (MTZs).

A

F Non-ablative.

116
Q

In MTZs , the epidermis is left intact, allowing for rapid repopulation of the ablated columns of tissue.

A

T

117
Q

Re-epithelisiation after fractional laser treatment is completed within 2 days following treatment.

A

F 1 day.

118
Q

Healing post fractional laser takes place through extrusion of microepidermal necrotic debris (MEND), which represents damaged epidermal components.

A

T

119
Q

MEND is clinically manifest as superficial exfoliation.

A

T

120
Q

During the reparative phase after non-ablative fractional laser, the skin appears erythematous.

A

F Bronze.

121
Q

Treatment of complete cosmetic units, or the whole face, is generally recommended with non-ablative fractional laser.

A

T

122
Q

MTZs are completely replaced by new collagen over the course of 6 months.

A

F 3 months.

123
Q

The two treatment parameters in non-ablative fractional laser are the treatment energy and the treatment density (ie. the total number of MTZs per square cm.

A

T

124
Q

For scarring purposes, higher treatment energies are used with lower treatment densities for non-ablative fractional lasers.

A

T

125
Q

For textural improvement with non-ablative fractional lasers, a medium energy is utilised.

A

T

126
Q

With non-ablative fractional lasers, pigmentary disturbances are best treated with lower treatment energies which allow for deeper penetration.

A

F More superficial penetration.

127
Q

Darker skin phototypes should not be treated with non-ablative fractional lasers.

A

F Treat safely by reducing total treatment density while maintaining energy setting.

128
Q

Melasma can paradoxically darken following fractional photothermolysis.

A

T

129
Q

For topical anaesthesia, preparations containing tetracaine should be avoided in patients with a known allergy to sulfa-containing medications.

A

T

130
Q

The expected side effects of fractional non-ablative laser (erythema, oedema, xerosis) usually resolve within 2 weeks.

A

F 4 days.

131
Q

Reactivation of herpes labialis tends not to occur with non-ablative laser skin remodelling.

A

F Can occur due to intense heat produced by laser.

132
Q

Non-ablative dermal remodelling treatments are typically delivered at monthly intervals, with final clinical results taking several months after laser irradiation to be realised.

A

T

133
Q

The topical photosensitiser aminolevulinic acid (ALA) is a 20% concentration solution.

A

T

134
Q

The topical photosensitiser methyl aminolevulinate cream (MAL) is commercially available as a 100mg/g cream.

A

F 160mg/g cream.

135
Q

Both ALA and MAL are strongly absorbed into sun-damaged cells and NMSCs, but not the pilosebaceous unit.

A

F Are absorbed into pilosebaceous unit.

136
Q

ALA and MAL are transformed via the heme pathway into their active form, protoporphyrin IX (PpIX).

A

T

137
Q

ALA should be used with a blue light source of 630nm peak output for PDT.

A

F 417nm peak output.

138
Q

MAL cream under occlusion for 3 hours followed by illumination with a red light source for PDT.

A

T 630nm peak output.

139
Q

After PDT, post-treatment crusting and erythema typically resolve within 2 days.

A

F Persist up to 10 days.

140
Q

PDT can improve fine lines, skin texture, erythema and pigmentation.

A

T

141
Q

Patients must adhere to strict sun and bright light avoidance for 48 hours after PDT.

A

T

142
Q

There are no contraindications for PDT – it is a safe treatment method for NMSCs, AKs and photodamage.

A

F CIs incl porphyrin disorder, photosensitivity disorder or photosensitising meds.

143
Q

Topical anaesthesia is required prior to application of the light source in PDT.

A

T

144
Q

Forced air cooling devices can be used to alleviate any discomfort associated with PDT.

A

T

145
Q

During the illumination, short breaks with cold water mists should not be used to help patients better tolerate the procedure.

A

F Can be used.

146
Q

MAL cream should be removed prior to light activation during PDT.

A

T

147
Q

Eye protection does not need to be worn during PDT.

A

F

148
Q

For photodamage, PDT can be repeated monthly until desired cosmetic results are achieved.

A

T

149
Q

Any remaining lesion after PDT for AKs/photodamage should be treated with further cycles.

A

F These should be biopsied.

150
Q

After light activation during PDT, the skin should not be cleansed.

A

F Should cleanse thoroughly w mild soap/water.

151
Q

Further activation of PpIX can occur for up to 48 hours after PDT.

A

T

152
Q

Phototoxicity after PDT should to be treated urgently with systemic corticosteroids, emollient and ice to avoid scarring or dyspigmentation.

A

T

Surgical MCQs (44 decks)

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