Oral cancer is a growing public health concern, particularly in South Asia, where it affects tens of thousands each year. In India alone, oral cancer accounts for 40 percent of all cancers, largely driven by the widespread use of tobacco-based products like gutka. The situation is worsened by limited access to early screening and treatment, especially in rural and underserved areas. Most cases are diagnosed at advanced stages, when treatment is more difficult and survival rates are lower.
To address this problem, researchers have developed a compact, affordable device that can both image suspicious lesions and deliver light-based therapy to treat them. Their report is published in Biophotonics Discovery .
The device uses a smartphone-coupled intraoral probe with specialized LEDs and filters to capture white-light and fluorescence images to pinpoint oral cancers. It also includes laser diodes to activate a light-sensitive compound called protoporphyrin IX (PpIX), which accumulates in cancerous tissue after the application of a precursor drug, 5-aminolevulinic acid (ALA). When exposed to light, PpIX produces reactive molecules that destroy cancer cells while sparing healthy tissue. This approach, known as photodynamic therapy, has shown promise in treating early oral cancers with minimal side effects.
To evaluate the device, the researchers conducted a series of preclinical tests. The team used tissue-mimicking phantoms and cell cultures to test the device's ability to detect PpIX fluorescence and monitor its breakdown (photobleaching) during treatment. The device showed a strong linear response to increasing PpIX concentrations and could detect changes in fluorescence that corresponded to effective light dosing.
Simulated 3D oral tissues embedded with cancer cells were used to assess how deeply the device could detect and treat lesions. The system successfully imaged PpIX fluorescence up to 2.5 mm deep and showed effective photobleaching at depths relevant to early-stage oral cancers. To further test the technology, the device was used to deliver photodynamic therapy and monitor treatment in an animal model. There, tumors treated with the device shrank significantly compared to untreated controls. Histological analysis revealed tumor cell death extending up to 3.5 mm deep, consistent with light delivery simulations.
Real-Time Monitoring and Feedback
One of the device's key features is its capability to monitor treatment in real time. By measuring the decrease in PpIX fluorescence during light exposure, the system provides feedback on how much therapeutic dose has been delivered. This could help ensure that each treatment is effective, even in settings without advanced medical infrastructure.
The researchers also used ratiometric imaging—comparing red and green fluorescence signals—to improve the accuracy of lesion detection and treatment monitoring. This method helps distinguish cancerous tissue from surrounding healthy areas, even in complex tissue environments.
The study demonstrates that a low-cost, portable device can perform both diagnosis and treatment of early oral cancer with promising accuracy and effectiveness. By combining imaging and therapy in a single tool, the technology could streamline care in regions where access to specialists is limited.
Future work will focus on clinical trials and refining the device for broader use. The team envisions a system that not only guides treatment but also adapts in real time, making photodynamic therapy more accessible and effective for patients around the world.
For details, see the original Gold Open Access article by S. Khan et al., " Enabling point of care optical diagnostics and treatment of oral lesions in resource-limited settings: preclinical development and evaluation of a low-cost theranostic intraoral device for image-guided photodynamic therapy ," Biophoton. Discovery 2(4) 042305 (2025), doi 10.1117/1.BIOS.2.4.042305 .
