Implantable ultrasonic imaging assembly for automated monitoring of internal organs.

An implantable miniaturized imaging device can be attractive in many clinical applications. They include automated, periodic, high-resolution monitoring of susceptible organs for early detection of an anomalous growth. In this paper, we propose an implantable ultrasonic imager capable of online high-resolution imaging of a region inside the body. A feasibility analysis is presented, with respect to design of such a system and its application to online monitoring of tumor growth in deep internal organs. We use ultrasound (US) imaging technology, as it is safe, low-cost, can be easily miniaturized, and amenable for long-term, point-of-care (POC) monitoring. The design space of the proposed system has been explored including form factor, transducer specifications and power/energy requirements. We have analyzed the effectiveness of the system in timely detection of anomalous growth in a case study through software simulations using a widely-accepted ultrasonic platform (Field II). Finally, through experimental studies using medical grade phantoms and an ultrasound scanner, we have evaluated the system with respect to its major imaging characteristics. It is observed that interstitial imaging under area/power constraints would achieve significantly better imaging quality in terms of contrast sensitivity and spatial resolution than existing techniques in deep, internal body parts, while maintaining the automated monitoring advantages.

Implantable ultrasonic dual functional assembly for detection and treatment of anomalous growth.

High Intensity Focused Ultrasound (HIFU) is emerging as an accurate, noninvasive method for ablation of certain primary and metastatic tumors. Typically, ablation is performed with an external therapeutic transducer. However, external HIFU treatment suffers from limitations of low therapeutic efficiency for ablation of tumors, deep in internal organs such as liver, kidney and brain. Interstitial HIFU through an internal transducer, implanted locally near the organ of interest, could alleviate some of these limitations. Furthermore, it can be attractive for point-of-care (POC) treatment. In this paper, we propose the design of a dual-functional implantable assembly for image-guided HIFU treatment of anomalous growth. It is realized by effective integration of a central HIFU array with two ultrasonic imaging arrays for high-resolution online monitoring and efficient treatment. We explore the design space for the implant and identify the major design parameters including the power requirement. Using a widely used simulation platform, we show that the proposed implant, besides providing a potential POC solution, achieves a better therapeutic performance for certain tumor positions in internal organs, than the extracorporeal HIFU treatment.

Low-power implantable ultrasound imager for online monitoring of tumor growth.

Clinicians all over the world agree that the most effective way to deal with a malignant tumor growth within internal organs is to detect it early. In most cases, early detection requires automated localized high resolution scanning of a region of interest--such as lungs, brain, small intestine, and gastro-intestinal tract. External or endoscopic ultrasound technologies are often not effective for imaging deep inside organs due to lack of adequate spatial resolution. In this paper, we propose using a miniature, low power implantable ultrasound imager for online monitoring of tumor growth in internal body parts. We explore the design space for such an implantable ultrasonic imaging system targeted to early detection or post-surgery monitoring of a malignant growth. The system can be placed locally in a susceptible region or for post-operative monitoring of relapse. The proposed system is capable of providing high-resolution image of a volume of interest at periodic intervals, using a relatively safe imaging technology, thus providing a chronic, reliable, and cost-effective monitoring option.