Study On Multi-modality And Multi-parameter Of Dynamic Development Of Melanoma

Melanoma is a kind of highly malignant tumor that mainly occurs on the skin.It has a rapid progression,strong invasion ability,insensitivity to radiotherapy and chemotherapy,and extremely poor prognosis.Therefore,early diagnosis has been a research focus for scholars at home and abroad for many years.Previous research has basically been carried out only on a certain technology,such as imaging or parameter measurement.It is only possible to analyze the manifestations or changes of tumors for this technology.Tumors can't be analyzed from multiple perspectives at the same time However,diversified analysis is essential for the study of tumorigenesis and development.Well then,establishing a suitable animal model to study the development and progression of tumors is of great significance for clinical detection and treatment of cutaneous melanoma.Based on that,this study established a stable nude mouse skin melanoma model firstly,then carried out a multi-modality modal and multi-parameter study on the dynamic development of tumorsIn the study of animal modeling,cutaneous melanoma in nude mouse was established by subcutaneous injection of A375 cell suspension and then were dissected to pathological verification.Results showed that the model of cutaneous melanoma in nude mice were successfully constructed,the tumor formation rate was 87.5%.Under the microscope,tumor cells vary in size and morphology,showing multiple differentiation.In addition,melanin particles could be seen in the cytoplasm.In the study of imaging monitoring,small animal high-frequency ultrasound and Optical Coherence Tomography(OCT)technology were used for non-invasive continuous monitoring of the development and progression of cutaneous melanoma.Then qualitative and quantitative analysis of images were performed.Results showed that OCT detected tumor formation at an earlier time than high-frequency ultrasound.With the growth of tumor,high-frequency ultrasound detected spots or bands of strong echos,and flattening of the upper dermis could be observed in OCT image.Furthermore,the SNR of HFUS and OCT were obviously enhanced over time.The tumor growth curve showed that OCT was more sensitive than high-frequency ultrasound in the measurement of depth in early stage,which made it suitable for dynamic monitoring of latency tumor.While high-frequency ultrasound could accurately measure the development of tumor volume and boundary division in the medium-late stage.In the study of in-vivo measurements of the electrical properties of tissues,the dielectric properties of nude mice were measured daily using the open-end coaxial probe method.The relative permittivity and conductivity of tissues were calculated through a specific algorithm,then based on this data,the trend of dielectric properties during the dynamic development of cutaneous melanoma was summarized.Results showed that before the tumor was observed by imaging,the open-axis coaxial probe method could measure and find the changes in the dielectric properties of leision tissues in vivo.During the dynamic development of cutaneous melanoma,its dielectric properties increased at first and then stabilized.In order to expanding the monitoring indicators of the dynamic development process of cutaneous melanoma,we added an excitation device besides OCT.The excitation device applied a certain pressure to the tissue and processed the precompression images and postcompression images to obtain the elastic distribution map of the tissue,which was attempted to analyze the elastic distribution and changes during the dynamic development of cutaneous melanoma.Results show that on the fifth day,the size and location of the tumor could be observed in the displacement map and strain map,and the axial strain inside the tumor was smaller than the surrounding tissue.As the tumor volume increased,the axial strain inside the tumor gradually decreased.In this paper,the multi-modality and multi-parameter study of the dynamic development of cutaneous melanoma were performed.The results of imaging monitoring shown that high-frequency ultrasound and OCT could monitor the development and progression of cutaneous melanoma in vivo,while at different stages the imaging effect differently.These could accumulate experience for related research on imaging monitoring.Dielectric properties in vivo measurement results were meaningful for early diagnosis of tumors.The preliminary experiments of elastography laied a foundation for the subsequent research.