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In this study, we sought to describe a novel imaging apparatus that is lightweight, inexpensive, and highly effective for use in colorectal diagnostic and treatment settings. Typical probes for use in colorectal ultrasonic imaging applications are developed for surgeons to diagnose and stage rectal tumors and image the rectum and anus. Here we outline a new technique and use it for colorectal imaging in an animal. This technique involves use of an ultrasound array module positioned along the axis of rotation such that improved rotation is possible. This module is in the shape of a linear rod with a rotary linear component that allows for emission of focused ultrasonic echo signals from a linear section of the probe. The usability of the transducer and rectal image quality are satisfactory in a porcine model with the technique proposed here, axial/lateral resolution as 0.96/2.24 mm with 6 dB applied through the contour map using the point spread function. When compared to currently available methods, this technique provides superior diagnostic 3D volumetric image quality with reduced acquisition time. Given this, the ultrasound device proposed here may prove a viable and preferable method to those currently available for urology and colorectal imaging applications. [ABSTRACT FROM AUTHOR]

Precise sentinel lymph node (SLN) identification is crucial not only for accurate diagnosis of micro-metastases at an early stage of cancer progression but also for reducing the number of SLN biopsies (SLNB) to minimize their severe side effects. Furthermore, it is desirable that an SLNB guidance should be as safe as possible in routine clinical use. Although there are currently various SLNB guidance methods for pre-operative or intra-operative assessment, none are ideal. We propose a real-time SLNB guidance method using contrast-enhanced tri-modal images (i.e., ultrasound, photoacoustic, and fluorescence) acquired by a recently developed hand-held tri-modal probe. The major advantage of tri-modal imaging is demonstrated here through an in vivo study of the technically-difficult case of nodal obstruction that frequently leads to false-negative results in patients. The results in a tumor model in rabbits and normal controls showed that tri-modal imaging is capable of clearly identifying obstructed SLNs and of indicating their metastatic involvement. Based on these findings, we propose an SLNB protocol to help surgeons take full advantage of the complementary information obtained from tri-modal imaging, including for pre-operative localization, intra-operative biopsy guidance and post-operative analysis. [ABSTRACT FROM AUTHOR]