Clinical assessment of a low-cost, hand-held, smartphone-attached intraoral imaging probe for 5-aminolevulinic acid photodynamic therapy monitoring and guidance.

Significance: India has one of the highest rates of oral squamous cell carcinoma (OSCC) in the world, with an incidence of 15 per 100,000 and more than 70,000 deaths per year. The problem is exacerbated by a lack of medical infrastructure and routine screening, especially in rural areas. New technologies for oral cancer detection and timely treatment at the point of care are urgently needed. Aim: Our study aimed to use a hand-held smartphone-coupled intraoral imaging device, previously investigated for autofluorescence (auto-FL) diagnostics adapted here for treatment guidance and monitoring photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence (FL). Approach: A total of 12 patients with 14 buccal mucosal lesions having moderately/well-differentiated micro-invasive OSCC lesions (<2 cm diameter and <5 mm depth) were systemically (in oral solution) administered three doses of 20 mg/kg ALA (total 60 mg/kg). Lesion site PpIX and auto-FL were imaged using the multichannel FL and polarized white-light oral cancer imaging probe before/after ALA administration and after light delivery (fractionated, total 100 J/cm2 of 635 nm red LED light). Results: The handheld device was conducive for access to lesion site images in the oral cavity. Segmentation of ratiometric images in which PpIX FL is mapped relative to auto-FL enabled improved demarcation of lesion boundaries relative to PpIX alone. A relative FL (R-value) threshold of 1.4 was found to segment lesion site PpIX production among the patients with mild to severe dysplasia malignancy. The segmented lesion size is well correlated with ultrasound findings. Lesions for which R-value was >1.65 at the time of treatment were associated with successful outcomes. Conclusion: These results indicate the utility of a low-cost, handheld intraoral imaging probe for image-guided PDT and treatment monitoring while also laying the groundwork for an integrated approach, combining cancer screening and treatment with the same hardware.

Clinical evaluation of a mobile, low-cost system for fluorescence guided photodynamic therapy of early oral cancer in India.

BACKGROUND: Morbidity and mortality due to oral cancer in India are exacerbated by a lack of access to effective treatments amongst medically underserved populations. We developed a user-friendly low-cost, portable fibre-coupled LED system for photodynamic therapy (PDT) of early oral lesions, using a smartphone fluorescence imaging device for treatment guidance, and 3D printed fibreoptic attachments for ergonomic intraoral light delivery. METHODS: 30 patients with T1N0M0 buccal mucosal cancer were recruited from the JN Medical College clinics, Aligarh, and rural screening camps. Tumour limits were defined by external ultrasound (US), white light photos and increased tumour fluorescence after oral administration of the photosensitising agent ALA (60 mg/kg, divided doses), monitored by a smartphone fluorescence imaging device. 100 J/cm2 LED light (635 nm peak) was delivered followed by repeat fluorescence to assess photobleaching. US and biopsy were repeated after 7-17 days. This trial is registered with ClinicalTrials.gov, NCT03638622, and the study has been completed. FINDINGS: There were no significant complications or discomfort. No sedation was required. No residual disease was detected in 22 out of 30 patients who completed the study (26 of 34 lesions, 76% complete tumour response, 50 weeks median follow-up) with up to 7.2 mm depth of necrosis. Treatment failures were attributed to large tumour size and/or inadequate light delivery (documented by limited photobleaching). Moderately differentiated lesions were more responsive than well-differentiated cancers. INTERPRETATION: This simple and low-cost adaptation of fluorescenceguided PDT is effective for treatment of early-stage malignant oral lesions and may have implications in global health.

Platform for ergonomic intraoral photodynamic therapy using low-cost, modular 3D-printed components: Design, comfort and clinical evaluation.

Oral cancer prevalence is increasing at an alarming rate worldwide, especially in developing countries which lack the medical infrastructure to manage it. For example, the oral cancer burden in India has been identified as a public health crisis. The high expense and logistical barriers to obtaining treatment with surgery, radiotherapy and chemotherapy often result in progression to unmanageable late stage disease with high morbidity. Even when curative, these approaches can be cosmetically and functionally disfiguring with extensive side effects. An alternate effective therapy for oral cancer is a light based spatially-targeted cytotoxic therapy called photodynamic therapy (PDT). Despite excellent healing of the oral mucosa in PDT, a lack of robust enabling technology for intraoral light delivery has limited its broader implementation. Leveraging advances in 3D printing, we have developed an intraoral light delivery system consisting of modular 3D printed light applicators with pre-calibrated dosimetry and mouth props that can be utilized to perform PDT in conscious subjects without the need of extensive infrastructure or manual positioning of an optical fiber. To evaluate the stability of the light applicators, we utilized an endoscope in lieu of the optical fiber to monitor motion in the fiducial markers. Here we showcase the stability (less than 2 mm deviation in both horizontal and vertical axis) and ergonomics of our applicators in delivering light precisely to the target location in ten healthy volunteers. We also demonstrate in five subjects with T1N0M0 oral lesions that our applicators coupled with a low-cost fiber coupled LED-based light source served as a complete platform for intraoral light delivery achieving complete tumor response with no residual disease at initial histopathology follow up in these patients. Overall, our approach potentiates PDT as a viable therapeutic option for early stage oral lesions that can be delivered in low resource settings.

Development and evaluation of a low-cost, portable, LED-based device for PDT treatment of early-stage oral cancer in resource-limited settings.

BACKGROUND: Photodynamic therapy (PDT) using δ-aminolevulinic acid (ALA) photosensitization has shown promise in clinical studies for the treatment of early-stage oral malignancies with fewer potential side effects than traditional therapies. Light delivery to oral lesions can also carried out with limited medical infrastructure suggesting the potential for implementation of PDT in global health settings. OBJECTIVES: We sought to develop a cost-effective, battery-powered, fiber-coupled PDT system suitable for intraoral light delivery enabled by smartphone interface and embedded electronics for ease of operation. METHODS: Device performance was assessed in measurements of optical power output, spectral stability, and preclinical assessment of PDT response in ALA-photosensitized squamous carcinoma cell cultures and murine subcutaneous tumor xenografts. RESULTS: The system achieves target optoelectronic performance with a stable battery-powered output of approximately 180 mW from the fiber tip within the desired spectral window for PpIX activation. The device has a compact configuration, user friendly operation and flexible light delivery for the oral cavity. In cell culture, we show that the overall dose-response is consistent with established light sources and complete cell death of ALA photosensitized cells can be achieved in the irradiated zone. In vivo PDT response (reduction in tumor volume) is comparable with a commercial 635 nm laser. CONCLUSIONS: We developed a low-cost, LED-based, fiber-coupled PDT light delivery source that has stable output on battery power and suitable form factor for deployment in rural and/or resource-limited settings. Lasers Surg. Med. 9999:1-7, 2018. © 2018 Wiley Periodicals, Inc.

Low-cost photodynamic therapy devices for global health settings: Characterization of battery-powered LED performance and smartphone imaging in 3D tumor models.

A lack of access to effective cancer therapeutics in resource-limited settings is implicated in global cancer health disparities between developed and developing countries. Photodynamic therapy (PDT) is a light-based treatment modality that has exhibited safety and efficacy in the clinic using wavelengths and irradiances achievable with light-emitting diodes (LEDs) operated on battery power. Here we assess low-cost enabling technology to extend the clinical benefit of PDT to regions with little or no access to electricity or medical infrastructure. We demonstrate the efficacy of a device based on a 635 nm high-output LED powered by three AA disposable alkaline batteries, to achieve strong cytotoxic response in monolayer and 3D cultures of A431 squamous carcinoma cells following photosensitization by administering aminolevulinic acid (ALA) to induce the accumulation of protoporphyrin IX (PpIX). Here we characterize challenges of battery-operated device performance, including battery drain and voltage stability specifically over relevant PDT dose parameters. Further motivated by the well-established capacity of PDT photosensitizers to serve as tumour-selective fluorescence contrast agents, we demonstrate the capability of a consumer smartphone with low-cost add-ons to measure concentration-dependent PpIX fluorescence. This study lays the groundwork for the on-going development of image-guided ALA-PDT treatment technologies for global health applications.

Rapid, low-cost fluorescent assay of ß-lactamase-derived antibiotic resistance and related antibiotic susceptibility.

Antibiotic resistance (AR) is increasingly prevalent in low and middle income countries (LMICs), but the extent of the problem is poorly understood. This lack of knowledge is a critical deficiency, leaving local health authorities essentially blind to AR outbreaks and crippling their ability to provide effective treatment guidelines. The crux of the problem is the lack of microbiology laboratory capacity available in LMICs. To address this unmet need, we demonstrate a rapid and simple test of ß -lactamase resistance (the most common form of AR) that uses a modified ß -lactam structure decorated with two fluorophores quenched due to their close proximity. When the ß -lactam core is cleaved by ß -lactamase, the fluorophores dequench, allowing assay speeds of 20 min to be obtained with a simple, streamlined protocol. Furthermore, by testing in competition with antibiotics, the ß -lactamase-associated antibiotic susceptibility can also be extracted. This assay can be easily implemented into standard lab work flows to provide near real-time information of ß -lactamase resistance, both for epidemiological purposes as well as individualized patient care.