Mr. Richard Allen Profile

Richard Allen

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Publications (2)

SPIE Journal Paper | 26 August 2023 Open Access

Smartphone-based dual radiometric fluorescence and white-light imager for quantification of protoporphyrin IX in skin

Alberto J. Ruiz, Richard Allen, Mia K. Giallorenzi, Kimberley S. Samkoe, M. Shane Chapman, Brian W. Pogue

JBO, Vol. 28, Issue 08, 086003, (August 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.8.086003

KEYWORDS: Imaging systems, Photodynamic therapy, Tunable filters, Skin, Blood, Fluorescence, Photobleaching, Light emitting diodes, Cameras, Image filtering

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SignificanceThe quantification of protoporphyrin IX (PpIX) in skin can be used to study photodynamic therapy (PDT) treatments, understand porphyrin mechanisms, and enhance preoperative mapping of non-melanoma skin cancers.AimWe aim to develop a smartphone-based imager for performing simultaneous radiometric fluorescence (FL) and white light (WL) imaging to study the baseline levels, accumulation, and photobleaching of PpIX in skin.ApproachA smartphone-based dual FL and WL imager (sDUO) is introduced alongside new radiometric calibration methods for providing SI-units of measurements in both pre-clinical and clinical settings. These radiometric measurements and corresponding PpIX concentration estimations are applied to clinical measurements to understand mechanistic differences between PDT treatments, accumulation differences between normal tissue and actinic keratosis lesions, and the correlation of photosensitizer concentrations to treatment outcomes.ResultsThe sDUO alongside the developed methods provided radiometric FL measurements (nW / cm2) with a demonstrated sub nanomolar PpIX sensitivity in 1% intralipid phantoms. Patients undergoing PDT treatment of actinic keratosis (AK) lesions were imaged, capturing the increase and subsequent decrease in FL associated with the incubation and irradiation timepoints of lamp-based PDT. Furthermore, the clinical measurements showed mechanistic differences in new daylight-based treatment modalities alongside the selective accumulation of PpIX within AK lesions. The use of the radiometric calibration enabled the reporting of detected PpIX FL in units of nW / cm2 with the use of liquid phantom measurements allowing for the estimation of in-vivo molar concentrations of skin PpIX.ConclusionsThe phantom, pre-clinical, and clinical measurements demonstrated the capability of the sDUO to provide quantitative measurements of PpIX FL. The results demonstrate the use of the sDUO for the quantification of PpIX accumulation and photobleaching in a clinical setting, with implications for improving the diagnosis and treatment of various skin conditions.

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Proceedings Article | 5 March 2021 Presentation

Open-source smartphone platform for quantitative imaging and analysis in point-of-care applications

Alberto Ruiz, Richard Allen, Ethan P. LaRochelle, Kimberley Samkoe, Brian Pogue

Proceedings Volume 11632, 116320J (2021) https://doi.org/10.1117/12.2583193

KEYWORDS: Point-of-care devices, Measurement devices, Information operations, Imaging devices, Skin cancer, Photodynamic therapy, Medical imaging, Image processing, Image analysis, Heart

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