Biomedical subjects

Abhilash Pandya

Publications and source records attributed to Abhilash Pandya.

5 recordsLinked to original sources

PubMed2005

Design, implementation and accuracy of a prototype for medical augmented reality.

OBJECTIVE: This paper is focused on prototype development and accuracy evaluation of a medical Augmented Reality (AR) system. The accuracy of such a system is of critical importance for medical use, and is hence considered in detail. We analyze the individual error contributions and the system accuracy of the prototype. MATERIALS AND METHODS: A passive articulated arm is used to track a calibrated end-effector-mounted video camera. The live video view is superimposed in real time with the synchronized graphical view of CT-derived segmented object(s) of interest within a phantom skull. The AR accuracy mostly depends on the accuracy of the tracking technology, the registration procedure, the camera calibration, and the image scanning device (e.g., a CT or MRI scanner). RESULTS: The accuracy of the Microscribe arm was measured to be 0.87 mm. After mounting the camera on the tracking device, the AR accuracy was measured to be 2.74 mm on average (standard deviation = 0.81 mm). After using data from a 2-mm-thick CT scan, the AR error remained essentially the same at an average of 2.75 mm (standard deviation = 1.19 mm). CONCLUSIONS: For neurosurgery, the acceptable error is approximately 2-3 mm, and our prototype approaches these accuracy requirements. The accuracy could be increased with a higher-fidelity tracking system and improved calibration and object registration. The design and methods of this prototype device can be extrapolated to current medical robotics (due to the kinematic similarity) and neuronavigation systems.

Humans↗

PubMed2004

Raman spectroscopy for neoplastic tissue differentiation: a pilot study.

BACKGROUND: Several changes occur during the transformation of normal tissue to neoplastic tissue. Such changes in molecular composition can be detected by Raman spectroscopy. Raman spectroscopy is a nondestructive method of measuring these changes, which suggests the possibility of real-time diagnosis during medical procedures. METHODS: This study seeks to evaluate the ability of Raman spectra to distinguish tissues. The Raman signatures of normal kidney, lung, and liver tissue samples from pigs and rats were characterized in vitro. Further, a human neuroblastoma and a hepatoblastoma, obtained at resection were also studied. RESULTS: The Raman spectra of the animal samples of kidney, liver, and lung are distinctly different in the intensity distribution of the Raman peaks. Further, the spectra of a given organ from pigs and rats, although similar, were different enough to distinguish between the 2 animals. In the patient tissues, the Raman spectra of normal liver, viable tumor, and fibrotic hepatoblastoma were very different. Fibrotic tissue showed a greater concentration of carotenoids, whereas viable tissue was rich in proteins and nucleic acids. The normal tissue showed both components. Similar differences were also seen in the neuroblastoma tissue. CONCLUSIONS: The results of this study show the potential use of Raman spectroscopy in clinical diagnosis.

Animals↗

PubMed2004

Robotics technology: a journey into the future.

Some major technologic improvements are needed for robotic technology to reach its ultimate potential, which includes better visualization, tactile sensing, diagnostic sensing, and miniaturization. This article gives a vision of the future of robotic technology with respect to these improvements.

Diagnostic Techniques and Procedures↗

PubMed2004

Development and human factors analysis of neuronavigation vs. augmented reality.

This paper is focused on the human factors analysis comparing a standard neuronavigation system with an augmented reality system. We use a passive articulated arm (Microscribe, Immersion technology) to track a calibrated end-effector mounted video camera. In real time, we superimpose the live video view with the synchronized graphical view of CT-derived segmented object(s) of interest within a phantom skull. Using the same robotic arm, we have developed a neuronavigation system able to show the end-effector of the arm on orthogonal CT scans. Both the AR and the neuronavigation systems have been shown to be within 3mm of accuracy. A human factors study was conducted in which subjects were asked to draw craniotomies and answer questions to gage their understanding of the phantom objects. The human factors study included 21 subjects and indicated that the subjects performed faster, with more accuracy and less errors using the Augmented Reality interface.

Adult↗

PubMed2002

The application accuracy of the NeuroMate robot--A quantitative comparison with frameless and frame-based surgical localization systems.

The NeuroMatetrade mark robot system (Integrated Surgical Systems, Davis, CA) is a commercially available, image-guided, robotic-assisted system used for stereotactic procedures in neurosurgery. In this article, we present a quantitative comparison of the application accuracy of the NeuroMate with that of standard frame-based and frameless stereotactic techniques. The article discusses a five-way application accuracy comparison study. The variables of our comparison and their mean errors are as follows: (1) with the robot in a frame-based configuration, the RMS was 0.86 +/- 0.32 mm; (2) with the robot in the frameless configuration, the RMS was 1.95 +/- 0.44 mm; (3) in a standard stereotactic (ZD) frame-based approach, the RMS was 1.17 +/- 0.25 mm; (4) with an infrared tracking system using the frame for fiducial registration, the RMS was 1.47 +/- 0.45 mm; (5) with an infrared tracking system using screw markers for registration, the RMS was 0.68 +/- 0.26 mm. The study was performed with 2-mm sections of CT scans. These results show that the application accuracy of the frame-based NeuroMate robot is comparable to that of standard localizing systems, whether they are frame-based or infrared tracked.

Equipment Design↗