## 1 Introduction  
Breast cancer is one of the most harmful diseases to women in today's society. Therefore, early detection and early treatment of breast cancer is particularly crucial [1]. The breast is made up of breast glands and other soft tissues without bones, which the cancerous tissues have higher density [2; 3]. In order to avoid the harm of false positive to women, it is necessary to develop highly sensitive and specific diagnostic tools for early detection of breast cancer [4]. At present, the imaging technology for breast cancer mainly includes X-ray mammography, Magnetic resonance imaging (MRI) and ultrasound [5]. X-ray mammography has the advantages of high sensitivity and high specificity to calcification points [6]. Whereas, early lesion is small, similar to the density of surrounding glands and the boundary is not clear, hence the imaging effect in breast detection is not obvious [7]. Besides, because of the radiation hazards, early screening is not appropriate [8]. Although MRI has higher sensitivity, the specificity is rather poor [9]. In addition, its disadvantages are high costs and long inspection time, which is not conducive to early screening [10; 11; 12]. Likewise, breast ultrasound relies heavily on the doctor's interpretation and is often used as a supplementary tool [13; 14]. In general, biopsy is the gold standard for the diagnosis of breast cancer, which show that there are a lot of false-positive cases diagnosed by ultrasound imaging [15; 16; 17; 18]. Ultrasound computer tomography (USCT) is a potential candidate for the imaging of breast cancer [19; 20]. The simultaneous recording of reflection, speed of sound and attenuation images is the key superiority of the USCT system [21]. Comfort, safety and 3D imaging are the potential clinical benefits of ultrasound tomography [22; 23].  
Three-dimensional USCT, which is a new ultrasound imaging technology, promises high quality images with satisfactory reproducibility and could offer a better chance for survival by the detection of cancers at the early stage [24; 25]. One problem that exists with the image reconstruction process is the assumption of 2D geometry while the object imaged is in 3D [26]. In a 2D image sequence, only clinicians with experience can estimate the size and shape of lesions and construct a three-dimensional geometric relationship between the lesion and its surrounding tissue [27]. This brings great difficulty to the accuracy and convenience of diagnosis and treatment and the specificity is poor [28]. Therefore, it is very necessary to visually demonstrate the collection data of USCT on a computer with different perspective [29]. Breast data were obtained from different perspectives and then ultrasound imaging analysis was conducted to observe tissue lesion information retrospectively, so as to improve specificity, further reduce misdiagnosis rate and avoid the pain caused by biopsy.  
In this study, we addressed the multi-perspective imaging technology, which is used to diagnose breast lesions. A system with a cylindrical motion of four 1 \(\times\) 128 PMUT linear arrays was applied to acquire the whole volume data using the optimized segmented dynamic focusing technology in the reflection mode. The data reconstruction was performed at a constant angle and according to the Nth element respectively. The experiment platform was set up and an ultrasound tomography algorithm was used to generate the vertical slice, horizontal slice and three-dimensional imaging. Furthermore, the characteristics of each perspective image were compared and analyzed.