A Dynamic Ultraviolet Response Optical Phantom Guiding Dose Adjustment In Ultraviolet Laser Therapy

Laser medicine has developed rapidly in recent years,which has been widely used in freckle removal,nevus removal,hair removal,minimally invasive surgery,tumor treatment,and the corresponding discipline has established.The control of laser dose in clinical treatment is the key factor to determine the therapeutic effect and patient experience.The empirical trial based adjustment of clinical laser dose is the most adopted method,where the initial laser dose was set as the empiric value coming from similar cases to treat patients,then adjust the laser dose according to the curative effect.However,the empirical trial method is disadvantaged as the possible damage to the normal tissues during trial treatment and the long time to adjust the process.In order to establish a more convenient laser dose adjustment method to improve the treatment experience,we proposed a dynamic ultraviolet response optical phantom to guide the dose adjustment in ultraviolet laser therapy.The phantom can simulate the dynamic optical properties of tissues under ultraviolet(uv)light by using spiropyan material 's reversible photochromic properties.The phantom and in vitro rabbit skin are irradiated under a clinic 308 nm laser therapeutic apparatus at different doses,the rabbit skin tissue was then sliced for observation of tissue damage,and optical properties of the phantom are characterized under the self-built double integrating sphere system and portable diffuse reflection spectrum measurement system(test once every week in one month).The experimental results indicate that the phantom show different colors though the irradiation of uv laser in different dose,which proves the relationship between the color of the phantom and the laser dose.The reflectance spectra of the phantom and the rabbit skin show similar spectral variation trend within a certain wavelength range,indicating the possibility of the phantom to simulate the dynamic optical characteristics of the tissue under uv laser irradiation.In addition,the deviation of reflectance spectral valley at different test times in one month is less than 5%,indicating that the phantom has the ability to maintain its reverse-photochromic characteristics for a long time.Our study demonstrates the potential of dynamic uv response optical phantom to guide the laser dose adjustment in ultraviolet laser therapy.