Clinical evaluation of smartphone-based fluorescence imaging for guidance and monitoring of ALA-PDT treatment of early oral cancer.

Shakir Khan,Shaista Siddiqui,Stephen G Bown,Jonathan P Celli,Amjad P Khan,Hui Liu,Filip Cuckov,Paola L Alacron,Tayyaba Hasan,Syed Abrar Hasan,Liam Daly,Kafil Akhtar,Grant Rudd,Colin Hopper,Srivalleesha Mallidi,M A Bilal Hussain,Shahid Ali Siddiqui

doi:10.1117/1.jbo.25.6.063813

Abstract

.Significance: India has one of the highest rates of oral cancer incidence in the world, accounting for 30% of reported cancers. In rural areas, a lack of adequate medical infrastructure contributes to unchecked disease progression and dismal mortality rates. Photodynamic therapy (PDT) has emerged as an effective modality with potential for treating early stage disease in resource-limited settings, while photosensitizer fluorescence can be leveraged for treatment guidance.Aim: Our aim was to assess the capability of a simple smartphone-based device for imaging 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence for treatment guidance and monitoring as part of an ongoing clinical study evaluating low-cost technology for ALA-based PDT treatment of early oral cancer.Approach: A total of 29 subjects with diameter moderately/well-differentiated microinvasive ( depth) oral squamous cell carcinoma lesions (33 lesions total, mean area ) were administered ALA in oral solution and imaged before and after delivery of total light dose to the lesion surface. Smartphone-based fluorescence and white light (WL) images were analyzed and compared with ultrasound (US) imaging of the same lesions.Results: We present a comparative analysis of pre- and post-treatment fluorescence, WL, and US images of oral lesions. There was no significant difference in the distribution of lesion widths measured by fluorescence and US (mean widths of 14.5 and 15.3 mm, respectively) and linear regression shows good agreement (). In general, PpIX fluorescence images obtained prior to therapeutic light delivery are able to resolve lesion margins while dramatic photobleaching () is visible post-treatment. Segmentation of the photobleached area confirms the boundaries of the irradiated zone.Conclusions: A simple smartphone-based approach for imaging oral lesions is shown to agree in most cases with US, suggesting that this approach may be a useful tool to aid in PDT treatment guidance and monitoring photobleaching as part of a low-cost platform for intraoral PDT.

Highlights

The increasing incidence of head and neck cancers in South Asia has been described as a global health crisis.[1]
A simple smartphone-based approach for imaging oral lesions is shown to agree in most cases with US, suggesting that this approach may be a useful tool to aid in Photodynamic therapy (PDT) treatment guidance and monitoring photobleaching as part of a low-cost platform for intraoral PDT
Lesion areas obtained by fluorescence image data were validated by independent analysis of US images from the same sites, as well as a custom analysis based on HSV of WL images. These results indicate that the use of smartphonebased imaging can be used to inform the target area for light delivery without the need for more

Summary

Introduction

The increasing incidence of head and neck cancers in South Asia has been described as a global health crisis.[1]. We used 5-aminolevulinic acid (ALA as Levulan®, DUSA, SUN Pharmaceuticals, Inc.), a precursor for the photoactive derivative protoporphyrin IX (PpIX).[4] PpIX acts as a fluorescent probe and imparts antitumor toxicity when activated by light This dual functionality has been used successfully for image-guided treatment of various cancers, including those of the oral cavity.[5,6] In clinical settings, PpIX fluorescence and photobleaching make it effective as a diagnostic as well as a treatment monitoring tool.[7,8] Recently, a smartphone with fluorescence imaging capability has been used as a low-cost device for premalignant oral screening.[8] The wide availability and popularity of smartphones, in the developing countries, make this device promising as a low-cost, portable, and capable theragnostic cancer technology for global health.[9,10,11] Building on previous preliminary findings,[12] we report here an evaluation of this simple and low-cost fluorescence imaging approach for guidance and monitoring of PDT treatment in the clinic

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Results

Conclusion