Abstract: In this work, localizing a capsule endoscope within the gastrointestinal tract is addressed. It is assumed that the capsule is equipped with a magnet, and that a magnetic sensor network measures the flux from this magnet. We assume no prior knowledge on the source location, and that the measurements collected by the sensors are corrupted by thermal Gaussian noise only. Under these assumptions, we focus on determining the Cramer-Rao Lower Bound (CRLB) for the location of the endoscope. Thus, we are not studying specific estimators, but rather the theoretical performance of an optimal one. It is demonstrated that the CRLB is a function of the distance and angle between the sensor network and the magnet. By studying the CRLB with respect to different sensor array constellations, we are able to indicate favorable constellations.
Abstract: Ultra wideband (UWB) technology has big potential for applications in wireless body area networks (WBANs). The inherent characteristics of UWB signals make them suitable for the wireless interface of medical sensors. In particular, implanted medical wireless sensors for monitoring physiological parameters, automatic drug provision, etc. can benefit greatly from this ultra low power (ULP) interface. As with any other wireless technology, accurate knowledge of the channel is necessary for the proper design of communication systems. Only a few models that describe the radio propagation inside the human body have been published. Moreover, there is no comprehensive UWB in-body propagation model that includes the frequency-dependent attenuation. Hence, this paper extends a statistical model for UWB propagation channels inside the human chest in the 1-6 GHz frequency range by including the frequency-dependent attenuation. This is done by modeling the spectrum shape of distorted pulses at different depths inside the human chest. The distortion of the pulse was obtained through numerical simulations using a voxel representation of the human body. We propose a mathematical expression for the spectrum shape of the distorted pulses that act as a window function to reproduce the effects of frequency-dependent attenuation.
Abstract: There is an increasing demand to discuss diagnostic images and reports of difficult cases with experienced staff. A possible solution besides physically transporting patients and material is to use high-speed communication networks to transfer images and reports electronically. With the web application PACSflow we have developed a solution to transfer images, reports, and messages as a single package in a one-step procedure. The PACSflow is an interoperable and standard compliant web-based application, which gives clinicians a user-friendly interface for their work on a daily basis. The solution assumes that the diagnostic images are compatible with the digital imaging and communications in medicine (DICOM) format. The Department of Cardiology at the Rikshospitalet University Hospital in Oslo, Norway, and the Department of Internal Medicine at the Sørlandet Sykehus in Arendal, Norway, are making clinical use of the system. Initial tests indicate that use of PACSflow has reduced the time required to prepare and transfer data by a factor of 3.
Abstract: Patient monitoring devices supporting wireless transmission can facilitate transport and ambulation of patients in hospitals. To replace wired sensors with wireless sensors, the accuracy and resistance to interference of the wireless sensors have to be documented. We compared the performance of a wireless arterial blood pressure biomedical sensor prototype with standard wired sensors in a clinical setting. Four patients undergoing laparoscopic abdominal surgery were recruited for testing of the device. Lines to a wireless arterial blood pressure sensor and standard wired sensor were connected to the same arterial cannula inserted in the right radial artery. Data from both systems were logged for postprocedure statistical comparison. During the procedure, 13 other electric devices were used, either continuously or intermittently. A sample-by-sample comparison was performed for both wired and wireless data. Statistical tests showed mean difference of 0.71, standard deviation of 0.14, and confidence interval of -1.28 to 1.56), indicating no significant electromagnetic interference on invasive arterial blood pressure monitoring caused by biomedical devices used during surgery. The wireless pressure biomedical sensor with Bluetooth wireless transmission of signals did not interfere with biomedical devices used in the operating room or vice versa.
Abstract: The Wireless Sensors in Healthcare Project focused on the implementation of wireless technology in healthcare. Wireless biomedical sensors for monitoring of continuous invasive arterial blood pressure were developed and evaluated under controlled conditions during laparoscopic surgery. The project has resulted in the first publication of clinical use of a wireless biomedical sensor for invasive measurement of arterial blood pressure in a pilot study. A second demonstrator for wireless clinical decision support based on the first demonstrator was developed. Wireless technologies used were Bluetooth, wireless local area network and GPRS/mobile telephones. Further research is needed to evaluate the wireless clinical decision support system. Critical care nurses and nurse anesthetists are potential users of wireless technology. Their clinical expertise is important in development of-, and future use of wireless technology.
Abstract: The Wireless Sensors in Healthcare Project focused on the implementation of wireless technology in healthcare. Wireless biomedical sensors for monitoring of continuous invasive arterial blood pressure were developed and evaluated under controlled conditions during laparoscopic surgery. The project has resulted in the first publication of clinical use of a wireless biomedical sensor for invasive measurement of arterial blood pressure in a pilot study. A second demonstrator for wireless clinical decision support based on the first demonstrator was developed. Wireless technologies used were Bluetooth, wireless local area network and GPRS/mobile telephones. Further research is needed to evaluate the wireless clinical decision support system. Critical care nurses and nurse anesthetists are potential users of wireless technology. Their clinical expertise is important in development of-, and future use of wireless technology.
Abstract: Patient monitoring devices supporting wireless transmission can facilitate transport and ambulation of patients in hospitals. To replace wired sensors with wireless sensors, the accuracy and resistance to interference of the wireless sensors have to be documented. We compared the performance of a wireless arterial blood pressure biomedical sensor prototype with standard wired sensors in a clinical setting. Four patients undergoing laparoscopic abdominal surgery were recruited for testing of the device. Lines to a wireless arterial blood pressure sensor and standard wired sensor were connected to the same arterial cannula inserted in the right radial artery. Data from both systems were logged for postprocedure statistical comparison. During the procedure, 13 other electric devices were used, either continuously or intermittently. A sample-by-sample comparison was performed for both wired and wireless data. Statistical tests showed mean difference of 0.71, standard deviation of 0.14, and confidence interval of -1.28 to 1.56), indicating no significant electromagnetic interference on invasive arterial blood pressure monitoring caused by biomedical devices used during surgery. The wireless pressure biomedical sensor with Bluetooth wireless transmission of signals did not interfere with biomedical devices used in the operating room or vice versa.
Abstract: Thermotherapeutic tools are increasingly used for tissue ablation, although the intra-operative monitoring is not adequate for such procedures. This is a main challenge for more extensive use of any ablative technique. The present work focuses on treatment of hepatic tumours by cryo therapy. For any thermotherapeutic tool there are specific thermal conditions that have to be met to ensure treatment adequacy. A software tool was made to calculate and visualise 3D temperature distributions during hepatic cryoablation combined with a 3D intra-operative navigation system. This system aids the user in placing the cryoprobe using an optical tracking system and 3D visualisation of the probe placement in relation to the target anatomy and the planned trajectory. 3D temperature distributions are calculated and visualized intra-operatively. The system is integrated with an interventional Magnetic Resonance 0.5T scanner. The system was tested in an animal experiment, exemplifying the usefulness of the navigation system and its ability to give intuitive feedback to the user on thermodynamic conditions induced in the target region. The system constitutes a novel tool for enhanced intra-operative control during cryoablative procedures, and motivates for studies using this tool to investigate predictors applied as indicators of treatment adequacy and patient outcome.
Abstract: Wireless sensors operating in unlicensed frequency bands have been proposed for monitoring physiological signals during surgical procedures in the operating room (OR). The IEEE 802.15.4/ZigBee wireless interface in the 2.4 GHz industrial-scientific-medical ...
Keywords: IABP, ISM band, WiFi, ZigBee, interference, wireless sensors
