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document
Does surface preparation alter ALA uptake in superficial non-melanoma skin cancer in vivo ? BACKGROUND/PURPOSE Photodynamic therapy ( PDT ) using aminolaevulinic acid ( ALA ) is widely used in the treatment of non-melanoma skin cancer . Surface preparation of the lesion is commonly performed before application of ALA but the extent of the preparation varies from centre to centre and there has been no study of its effects . The purpose of this study was to examine the effects of surface preparation on the local uptake of ALA by recording fluorescence from accumulated protoporphyrin IX ( PPIX ) . METHODS The study was performed on 16 lesions , either superficial basal cell carcinoma ( BCC ) or Bowen 's disease ( BD ) . Each half of the lesion was randomly assigned to ( a ) no surface preparation or ( b ) surface preparation ( randomly allocated to gentle curettage or abrasion with a spatula ) . ALA was left for 4 h ( BCC ) or 6 h ( BD ) . PPIX fluorescence was measured using an excitation wavelength of 405+/-5 nm and emission spectrum recorded using a photodiode array . Spectra were measured ( a ) before and ( b ) after surface preparation , ( c ) immediately before and ( d ) after laser irradiation at 630 nm . RESULTS The ratio of fluorescence after incubation to that before incubation was 6.1+/-1.2 in the non-prepared section . This increased slightly but not significantly to 6.8 +/-1.8 in the prepared section ( P < 0.1 ) . There was no significant difference between curettage and abrasion . There was also no significant difference in outcome after PDT . CONCLUSIONS The clinical assessment agrees with the fluorescence data as no significant difference was seen between prepared and unprepared halves of the lesion 12 months after PDT . Overall our data seem to suggest that for most BCC and BD lesions , surface preparation did not increase ALA uptake .
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Intervention_Pharmacological
aminolaevulinic acid ( ALA )
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Intervention_Physical
Surface preparation
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Intervention_Physical
surface preparation
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Intervention_Control
no surface preparation or
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Intervention_Physical
( b ) surface preparation ( randomly allocated to gentle curettage or abrasion with a spatula )
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Intervention_Physical
photodiode array
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Intervention_Physical
laser irradiation
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Outcome_Other
ALA uptake
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Outcome_Other
uptake of ALA
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Outcome_Other
PPIX fluorescence
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Outcome_Other
ratio of fluorescence after incubation
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Outcome_Other
curettage and abrasion .
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Outcome_Other
ALA uptake