Portable Measurement of Protoporphyrin IX in the Skin

Study Overview
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Brief Summary
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Photodynamic therapy (PDT) is increasingly used to treat superficial skin lesions, such as actinic keratosis (AK) and non-melanoma skin cancers, and has been demonstrated to be an effective and safe alternative to surgery. It is performed by applying a photosensitizing pro-drug, amino -levulinic acid (ALA) and then allowing the conversion to the metabolite Protoporphyrin IX (PpIX). While attempts to measure the concentration of this drug in the skin have been performed before, there remains limited research on an individuals' baseline level of PpIX which could lead to the customization of PDT. With the development of a new handheld, smart phone-associated device to measure red fluoresce intensity of PpIX, this measurement is now feasible. This is an observational single center quantitative study in which the investigators will take measurements of red fluoresce intensity of PpIX at various locations. This will then be correlated with the individuals age, oral temperature, diet, and skin type. The investigators hypothesize that the levels of PpIX will depend on all of these factors, including anatomical location. All data will be collected into the data collection form and then analyzed. The investigators will assess for how anatomical location, skin pigmentation, oral temperature, and other factors influence PpIX levels. Fitzpatrick skin type will be assessed by the provider to assess skin pigmentation. All of these factors will be correlated to the PpIX levels in 5 anatomical locations (forehead, cheeks, forearms, hands, and bald scalp where applicable) to determine which factors most greatly influence the red fluoresce intensity of PpIX.

Detailed Description
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Photodynamic Therapy (PDT) has gained popularity as an effective, non-scarring treatment for thin, non-hyperkeratotic actinic keratoses (AKs). Similar to the topical agents 5-fluorouracil and imiquimod, PDT is particularly useful when utilized as a field-directed therapy for the treatment of areas with multiple AKs and extensive sun damage. PDT consists of two steps: 1) the topical application of a photosensitizer agent aminolevulinic acid (ALA), which is preferentially converted to the photosensitive protoporphyrin IX (PpIX) in precancerous and neoplastic cells, and 2) controlled exposure to a visible wavelength light source. Current methodologies utilize a one-size-fits-all approach with regard to duration of incubation with photosensitizing agents and illumination. Moreover, patients frequently experience pain after long PDT prodrug incubation. Better characterization of photosensitization in PDT can help tailor incubation and overall treatment time to minimize treatment duration and discomfort while maximizing clearance of the target lesions. The direct measurement of PpIX is a promising, yet rarely performed test that may help determine the appropriate PDT treatment time, the need for re-treatment or adjuvant therapy, and potential efficacy of treatment. Point-probe measurements have shown extreme heterogeneity between PpIX levels in different patients and among different lesions in the same patient. However, these point-probe measurements are unable to account for the variance in PpIX production in different parts of the skin because of their relatively limited field of view. The recent development of a low-cost, smart phone-based, wide-field fluorescence dosimetry imaging system to map PpIX levels onto a 2D image allows for handheld, real-time analysis of PpIX levels in human skin. Initial unpublished clinical results have shown its utility in human subjects. However, a more extensive characterization of the factors that influence baseline in PpIX has yet to be performed. This study intends to elaborate these inter-and intra-individual variances, including analysis of changes in PpIX concentrations based on anatomical location, age, diet, temperature, pigmentation, and previous skin damage.

Official Title
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Portable Measurement of Protoporphyrin IX in the Skin

Conditions
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Photodynamic Therapy, Protoporphyrin IX

Intervention / Treatment
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* Device: Portable Apple Smart Phone Protoporphyrin IX Spectrometer Camera


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients and staff appearing at the Dartmouth-Hitchcock Medical Center Heater Road Dermatology Clinic who are aged 18 years and older Exclusion Criteria: Pregnant women Women who are breast-feeding Adults unable to consent Individuals who are not yet adults Prisoners.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Portable Apple Smart Phone Protoporphyrin IX Spectrometer Camera|This is a portable device that uses a camera to non-invasively and efficiently measure the level of protoporphyrin IX in various areas skin. This camera will be used in all participants to measure the level of protoporphyrin IX in various areas of skin as detailed in the study description.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Protoporphyrin IX levels on the skin | Measure change in protoporphyrin IX levels in the skin of the forehead, malar cheek, dorsal hand, and dorsal forearm patients, as well as the bald scalp in male patients | At baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of oral temperature on change in protoporphyrin IX levels at baseline and at serial time points after Ameluz application (the intervention) | Measure oral in temperature and compare it to protoporphyrin levels. | At baseline | 
| Effect of age on change in protoporphyrin IX levels at baseline and at serial time points after Ameluz application (the intervention) | Determine the relationship of participant age with change in protoporphyrin IX levels | At baseline | 
| Effect of Fitzpatrick skin type (skin pigmentation) on change in protoporphyrin IX levels | Determine the relationship of participant fitzpatrick skin type (skin pigmentation) with change in protoporphyrin IX levels | At baseline | 
| Effect of diet on change in protoporphyrin IX levels | Determine the relationship of participant diet with change in protoporphyrin IX levels | At baseline | 
| Effect of history of skin cancer on change in protoporphyrin IX levels | Determine the relationship of participant history of skin cancer with change in protoporphyrin IX levels | At baseline | 
| Effect of sex on change in protoporphyrin IX levels | Determine the relationship of participant sex with change in protoporphyrin IX levels | At baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Photodynamic Therapy, Actinic Keratoses, Protoporphyrin IX, Amino-levulinic acid