The investigators include patients who are found to have solid pancreatic mass on continuous imaging. All subjects are scanned by Fuji film su-9000 ultrasonic system. After the lesions are found, local sound velocity measurement technology will be used to measure the sound velocity in the lesions. Pathology diagnosis or clinical follow-up results will be regard as diagnostic gold standard to divide the patients into pancreatic cancer and pancreatic cancer group. The investigators will compare the sound velocity value if there is statistically significant difference between the two groups, build the receiver operating characteristic curve, calculation of pancreatic benign and malignant lesions of sound velocity threshold, and and the investigators will calculate the sensitivity, specificity, accuracy, positive predictive value and negative predictive value, to evaluate local sound velocity measurement in the diagnosis of pancreatic cancer clinical application value.
