Portable Measurement of Protoporphyrin IX in the Skin

November 18, 2025 updated by: Michael S. Chapman, Dartmouth-Hitchcock Medical Center
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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
219

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • New Hampshire
      • Lebanon, New Hampshire, United States, 03766
        • Dartmouth-Hitchcock Medical Center Heater Road Clinic

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 71 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Probability Sample

Study Population

Patient subjects will be recruited at the DHMC outpatient dermatology clinic. Patients presenting for their routine sessions or regularly scheduled follow-up dermatology appointments will be provided information about the study. Employees at this location will also have the opportunity to participate.

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Ameluz (amino-levulinic acid topical gel) Only
Ameluz is a topical gel approved for use in photodynamic therapy for treatment of actinic keratoses, among other skin conditions. It is being applied to all participants in this study to measure the levels of PpIX in different areas of skin as detailed in study description. This arm includes those participants who have not been prescribed photodynamic therapy and thus they will not receive any light treatment during this study.
Drug: Ameluz
Ameluz is a topical gel approved for use in photodynamic therapy for treatment of actinic keratoses.
Other Names:
  • amino-levulinic acid topical gel
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.
Active Comparator: Ameluz and Light Therapy
Ameluz is a topical gel approved for use in photodynamic therapy for treatment of actinic keratoses, among other skin conditions. It is being applied to all participants in this study to measure the levels of PpIX in different areas of skin as detailed in study description. For patients who have been prescribed photodynamic therapy, the investigators will perform one additional round of measurements of Protoporphyrin IX using our camera device, in addition to the other secondary outcomes including skin temperature.
Drug: Ameluz
Ameluz is a topical gel approved for use in photodynamic therapy for treatment of actinic keratoses.
Other Names:
  • amino-levulinic acid topical gel
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.
Device: Photodynamic Therapy Light
This blue light is FDA approved to work with the Ameluz gel as part of photodynamic therapy and works with the photosensitizing Ameluz gel to form reactive oxygen species that specifically target precancerous lesions, such as actinic keratoses, without damaging normal, non-cancerous skin.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Protoporphyrin IX levels on the skin
Time Frame: At baseline
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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)
Time Frame: At baseline
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)
Time Frame: At baseline
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
Time Frame: At baseline
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
Time Frame: At baseline
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
Time Frame: At baseline
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
Time Frame: At baseline
Determine the relationship of participant sex with change in protoporphyrin IX levels
At baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Dartmouth-Hitchcock Medical Center

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michael S Chapman, MD, MBA, Dartmouth-Hitchcock Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 20, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 20, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 24, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 8, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 10, 2020

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 21, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 18, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • D19167

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All of the individual participant data collected during the trial, after being de-identified

IPD Sharing Time Frame

Immediately following publication. No end date.

IPD Sharing Access Criteria

Anyone who wishes to access these data.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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