Vladimir Misic

Robot-Assisted prostate brachytherapy

In contemporary brachytherapy procedures, needle placement at the desired target is challenging due to a variety of reasons. A robot-assisted brachytherapy system can improve the needle placement and seed delivery resulting in enhanced patient care. In this paper we present a 16 DOF (degrees-of-freedom) robotic system (9DOF positioning module and 7 DOF surgery module) developed and fabricated for prostate brachytherapy. Techniques to reduce needle deflection and target movement have been incorporated after verifying with extensive experiments. Provisions for needle motion and force feedback have been included into the system for improving the robot control and seed delivery. Preliminary experimental results reveal that the prototype system is quite accurate (sub-millimeter) in placing brachytherapy needles.

In vivo cancer diagnosis with optical spectroscopy and acoustically induced blood stasis using a murine MCa35 model

Ultrasound-induced blood stasis has been observed for more than 30 years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive. The current work demonstrates ultrasound-induced blood stasis in murine normal leg muscle versus tumor-bearing legs, observed through noninvasive measurements of optical spectroscopy, and discusses possible diagnostic uses for this previously undesirable effect of ultrasound. We demonstrate that, using optical spectroscopy, effects of ultrasound can be used to differentiate tumor from normal leg muscle tissue in mice. Finally, we propose a novel diagnostic algorithm that quantitatively differentiates tumor from nontumor with maximum specificity 0.83, maximum sensitivity 0.79, and area under receiver-operating-characteristics curve 0.90.

Semi-automated Needling and Seed Delivery Device for Prostate Brachytherapy

In this paper we present a semi-automated device designed and developed to deliver radio-active seeds for treating prostate cancer. In the brachytherapy procedure a slander needle is inserted through the perineum and passed through different types of tissues. Thus, the needle experiences significant amount of force which may cause it to buckle and bend. In our design, we have considered the buckling force and insertion force on needle by collecting in-vivo data from real patient and performing in-vitro experiments. Techniques to reduce force and organ/tissue deformation have been implemented into this new design. To track the axial force on the needle for detecting pubic arch interference and to improve robotic control, we have incorporated three force sensors. Rigidity and factor of safety of the device has been analyzed using finite element method which was very useful for iterative design process

A method to minimize puncturing force and organ deformation

A robotic system providing force feedback and automation for minimally invasive heart surgery H. Mayer Æ I. Nagy Æ A. Knoll Æ E.U. Schirmbeck Æ R. Bauernschmitt Robotics and Embedded Systems Lab, Technical University Munich, Germnay Department of Cardiovascular Surgery, German Heart Center Munich, Germany Abstract We have developed an experimental system for robotic heart surgery, which provides force feedback and full Cartesian control on each of the four end effectors Currently the system is used to determine the degree of automation that can be included into surgical procedures. Therefore we have included an optical system with thread recognition and we provide assistance to the surgeon via automated knot-tying.

Encoding and processing of color engravings (using MRC)

Digitization of printed illustrations for archive purposes is not always a simple procedure, due to the varied nature of illustration processes. For example, colored engravings were once the predominant type of book illustrations. Due to the specific printing process they consist of regions of both very fine lines (high-frequency) and almost uniformly colored regions (low-frequency). In order to keep the compression rate high, compression algorithms tend to destroy the fine lines that are the essence of this type of image. However, the images compressed using the modified mixed raster content (MRC) compression scheme showed exceptional fidelity to their prototypes at low bit-rates when compared to alternate compression methods such as JPEG and JPEG2000. This paper presents the simple segmentation algorithm for fast separation of engraved and colored layers, as a part of the image processing process necessary for MRC scheme implementation. This is demonstrated on the case study of the William Blake Archive.

In vivo Optical Spectroscopy of Acoustically Induced Blood Stasis

Ultrasound-induced blood stasis has been observed for more than thirty years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive. The current work demonstrates ultrasound-induced blood stasis in murine tumor and nontumor tissue, observed through noninvasive measurements of optical spectroscopy, and discusses possible diagnostic uses for this previously undesirable effect of ultrasound

Tumor Detection in vivo with Optical Spectroscopy

Ultrasound induced blood stasis has been observed for a long time, but to date most experimental observations have been in vitro. In this paper we discuss a possible diagnostic use for this previously undesirable effect of ultrasound - tumor detection in vivo. We demonstrate that, using optical spectroscopy, effects of ultrasound can be used to differentiate tumor from non-tumor in murine tissue. Finally, we propose a novel diagnostic algorithm that quantitatively differentiates tumor from non-tumor with maximum specificity 0.83, maximum sensitivity 0.79, and area under ROC curve 0.90

Efficacy of Prostate Stabilizing Techniques during Brachytherapy Procedure

During the prostate brachytherapy procedure, multiple needles are inserted into the prostate and radioactive seeds are deposited. Stabilizing needles are first inserted to provide some rigidity and support to the prostate, ideally this will provide better seed placement and an overall improved treatment. However, there is much speculation regarding the effectiveness of using regular brachytherapy needles as stabilizers. In this study, we explored the efficacy of (1) two types of needles -18 gauge brachytherapy needle vs. 18 gauge hooked needle; and (2) parallel vs. angulated needle configurations to stabilize the prostate. Prostate phantom movement and needle insertion progression were imaged using ultrasound (US). The recorded images were analyzed and prostate displacement was computed from images using implanted artifacts. Experimentation allowed us to further understand the mechanics behind prostate stabilization. We observed superior stabilization by the hooked needles compared to the regular brachytherapy needles (more than 40% for parallel stabilization). Prostate movement was also reduced significantly when regular brachytherapy needles were in an angulated configuration as compared to the parallel configuration (approximately 40%). When the hooked needles were angled for stabilization, further improvement in decreased displacement was observed. In general, for convenience of dosimetric planning, all needles are desired to be in parallel and in this case, hooked needles are better suited to improve stabilization of the prostate. On the other hand, both regular and hooked needles appear to be equally effective in reducing prostate movement when they are in angulated configurations, which will be useful in robotic permanent seed implantation (PSI)

Morphological characterization of dithering masks

We present some novel tools for the analysis of blue- noise binary patterns. Unlike most of the existing methods that evaluate the frequency content of a given mask or its lower order statistics, our new metrics characterize the morphological content of a mask that is quantified using simple one-pass filtering. An analyti- cal filter expression is given. As a result, one can balance the struc- tural content of the mask—diagonal, vertical, and horizontal inter- connections of the majority (or minority) pixels—at the same level. In addition, it is possible to improve the overall mask quality by pre- scribing the occurrence of morphological shapes of connected pix- els. Examples of morphological analysis are given to demonstrate the different qualities of blue-noise and white-noise patterns.

Enhancement of colored engravings

Digitization of printed illustrations for archive purposes is not always a simple procedure. For example, colored engravings (a common book-illustration type of the XVIII and XIX century) consist of regions of both very fine lines and almost uniformly colored regions. In order to keep the compression rate high, compression algorithms tend to destroy fine lines (the high-frequency content) that are the essence of this type of image. However, the images compressed using the modified mixed raster content (mMRC) compression scheme retain the lines and show exceptional fidelity to their prototypes at low bit-rates when compared to alternate compression methods such as JPEG and JPEG2000. This paper presents the simple algorithm for data-filling of the MRC background layer, that improves the compression results, and - at the same time - enhances the reconstructed image. This is demonstrated on the case study of the colored engravings from the William Blake Archive.