Research On Fluorescence-based Technique In Early Screening Of Skin Cancer

Skin tumors are one of the most common diseases in the world.The key to the treatment of skin tumors is early screening.At present,early diagnosis techniques for skin tumors are more or less defective in early screening and early localization of skin tumors.Therefore,the goal of this project is to design a non-invasive skin tumor fluorescence imaging system to fill the gaps in fluorescence imaging for early screening of skin tumors.At the same time,the application of the imaging aid in the localization of early skin tumor lesions was discussed in the joint application of skin tumor imaging methods.This topic first studies the specific fluorescence principle of early skin tumors,and proposes technical indicators for subsequent system design.The specific fluorescence principle of skin tumors is Photodynamic Diagnosis(PDD).It is externally applied to the skin lesions by 5-aminolevulinic acid(5-ALA),then the photosensitizer protoporphyrin is accumulated in the tumor site.When irradiated with a 405 nm wavelength light source,635 nm fluorescence is generated at the tumor site.Different from normal skin tissue,this fluorescence can be used to locate the tumor site.A special fluorescence imaging detection system was developed for skin tumor fluorescence.The fluorescence imaging system includes a coaxial optical lens module and a fluorescent acquisition circuit module.The coaxial optical lens integrates the LED light source,the filter and the optical lens into one body,which can effectively excite the fluorescence and distinguish the fluorescence from the excitation light.The main work of the fluorescence acquisition circuit module has two parts.The first part completes the circuit schematic design and PCB design work.The second part is the circuit logic design.The logic design includes the overall structure of the system software;completing register configuration,CMOS image data read and transfer.The system’s power consumption is 1.5W and the resolution is 1920*1080,which meets the requirements of low power consumption,high resolution and small size.Design experiments to verify the feasibility of the dedicated fluorescence imaging detection system.The experiment was performed using mice with squamous cell carcinoma.As a result,the fluorescence imaging system successfully acquired early tumor fluorescence images,and the fluorescence images were able to distinguishnormal skin from tumor regions.The experimental results show that the principle of tumor fluorescence imaging discussed in this topic is correct,and the designed fluorescence imaging system can be used normally.Another experiment explores the positioning function of the dedicated fluorescence imaging detection system in the joint application of skin tumor imaging methods.This experiment uses a fluorescence imaging system and an ultrasound probe to acquire multi-dimensional images of normal skin and early skin tumors.The experimental results show that the fluorescence imaging system can locate early tumors and provide location information for subsequent skin ultrasound.