I. Introduction
Acupoints are special parts for treatment of diseases in body surface. They are not only the theoretical basis of acupuncture science, but also the core and focus of scientific research of this field [1]. The precise location of acupoints is of great significance to improve the curative effect of acupuncture. Therefore, many researchers have paid attention to the standardization of location of acupoints [2]. The existing standard of acupoint positioning mainly analyzes the standardized positioning of acupoints from the perspectives of anatomical knowledge, bone degree and folding, finger and inch positioning and so on [3]. The above traditional methods of acupoint location mainly focus on theory, mostly limited to the actual analysis of human anatomy, but lack of evaluation of functional information [3]. The wide application of biomedical imaging technique in this field not only well meets the needs of objectification and visualization in the research of acupoints, but also builds a new platform for the research of acupoints, which greatly promotes and deepens the research on acupoints. Ultrasound imaging is a non-invasive imaging modality, which can provide real-time dynamic images of the cross-section of the human body and clearly show the structure distribution around the acupoint [4]. It can be used as an image guidance tool for acupuncture. However, its imaging contrast of the needle relative to the surrounding tissue is not high, and it is not easy to obtain the specific location of the needle in tissues [5].