Abstract: A method to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter the high-field region of an MRI suite. The device used comprises either a screening portal or a compact, hand-held magnetic gradiometer and its electronics. The method places all of the sensor arrays in close proximity to all parts of a subject's body, for screening purposes.

Abstract: Methods and systems for a universally applicable, linear, signal processing framework for optimal detection, localization, and feature extraction of dipolar magnetic and electromagnetic (EM) targets. Such methods and systems provide the ability to, for example, simultaneously and optimally solve the problems of detection, localization and estimation of the dipole vector or target response matrix; be applicable to different types of magnetic or EMI sensor system; and be applicable to arbitrary combinations of sensor locations and orientations, and arbitrary spatial sampling. Such functionality is provided, in various aspects of the disclosure, with a quadrature matched filter algorithm for detecting and imaging magnetic dipoles to the more complex realm of single- and multi-channel EMI sensors.

Abstract: A method and apparatus to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter the high-field region of an MRI suite. The device comprises either a screening portal or a compact, hand-held magnetic gradiometer and its electronics. The device places all of the sensor arrays in close proximity to all parts of a subject's body, for screening purposes.

Abstract: A probe instrument using room-temperature sensor(s) that can measure variations in magnetic susceptibilities. The instrument has sufficient resolution to monitor paramagnetic materials in a human body, such as iron in a human liver, by noninvasively examining patients with iron-overload diseases. The instrument includes room temperature magnetic sensors, and detects the sample, that is, the tissue response to an alternating current field applied by an applied field coil. The applied field coil dimensions are chosen so that the applied field is optimized for maximum response from the liver while minimizing the effects due to the overlying abdominal tissue and at the same time not unduly increasing the sensitivity of the instrument to the lung. To overcome variations in the sensor output due to fluctuations in the applied field, change in the ambient temperature and mechanical relaxation of the instrument, the sensor-sample distance is modulated.

Abstract: Methods and apparatus for minimizing the effects of temperature drift in a magnetic susceptibility measurement instrument, such as an instrument used in pre-MRI screening for the presence of ferromagnetic foreign bodies. The magnetic field source and magnetic sensors can be combined into a single, rigid unit. The stability and sensitivity required in high quality magnetic susceptibility measurements can be achieved through symmetrical design of the source-sensor unit, minimization of thermal stresses, minimization of temperature variations, use of materials with low thermal expansion coefficients, or through appropriate combinations thereof. Use of patient eye movement where an eye is being screened, use of a water bag between the patient and the instrument, or use of telemedicine to facilitate performance of the necessary computations can also be incorporated.

Abstract: A method and apparatus to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter a security area. The device comprises either a screening portal or a compact, hand-held magnetic gradiometer and its electronics. The device places all of the sensor arrays in close proximity to all parts of a subject's body, for screening purposes.

Abstract: A method and apparatus to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter the high-field region of an MRI suite. The device comprises either a screening portal or a compact, hand-held magnetic gradiometer and its electronics. The device places all of the sensor arrays in close proximity to all parts of a subject's body, for screening purposes.

Abstract: A method and apparatus for sequentially exposing a region of a patient to a low level DC magnetic field, first without movement of the region to null the sensing apparatus, then with movement of the region to detect synchronous changes in the detected signal, indicative of a ferromagnetic foreign body in the region. The nulling and signal detection can take place at a plurality of test zone set points at increasing magnitudes of the applied magnetic field. The sensing apparatus can be nulled at each test zone set point prior to introduction of the patient.

Abstract: A method for pre-screening a patient for the presence of a ferromagnetic foreign body, prior to performance of an MRI procedure, using a low power portion of the MRI field to magnetize the foreign body for detection purposes.

Abstract: Methods are disclosed for non-invasive screening of the human body by rejecting the magnetic response from biological tissues in the region of interest and outputting data corresponding to the magnetic response of a ferromagnetic foreign body within the region of interest.

Abstract: Methods and apparatus for minimizing the effects of temperature drift in a magnetic susceptibility measurement instrument, such as an instrument used in pre-MRI screening for the presence of ferromagnetic foreign bodies. The magnetic field source and magnetic sensors can be combined into a single, rigid unit. The stability and sensitivity required in high quality magnetic susceptibility measurements can be achieved through symmetrical design of the source-sensor unit, minimization of thermal stresses, minimization of temperature variations, use of materials with low thermal expansion coefficients, or through appropriate combinations thereof. Use of patient eye movement where an eye is being screened, use of a water bag between the patient and the instrument, or use of telemedicine to facilitate performance of the necessary computations can also be incorporated.

Abstract: Method and apparatus for using magnetic susceptibility measurements to detect ferromagnetic foreign bodies (FFBs) in the eye. The method involves having the patient rotate his or her eyes, modulating the orientation and/or location of the FFB in relation to the sensing apparatus. This changing orientation or position will modulate the magnetic susceptibility signal from the FFB, without substantially changing the magnetic susceptibility response of the patient's body tissues. Consequently, modulation of the magnetic signal due to the motion of the eye will indicate the presence of an FFB in the eye. Eye movement may also be used in conjunction with the detection of ferromagnetic foreign bodies by means other than magnetic susceptibility measurements, such as x-rays and ultrasound.

Abstract: A probe instrument using room-temperature sensor(s) that can measure magnetic susceptibilities variations. The instrument includes room temperature magnetic sensors, and detects the sample, that is the tissue response to an applied field coil. The sensors that can be used include magnetoresistive, fluxgate and magnetoinductive sensors. The applied field coil dimensions are chosen so that the applied field is optimized for maximum response from the item of interest while minimizing the effects due to the overlying tissue and at the same time not unduly increasing the sensitivity of the instrument to adjacent organs. To minimize noise introduced in the sensor due to fluctuations in the applied field, the applied field is canceled at the position of the sensor. To overcome variations in the sensor output due to fluctuations in the applied field, change in the ambient temperature and mechanical relaxation of the instrument, the detector assembly is oscillated while the examined patient remains stationary.

Abstract: A method for rejecting the magnetic response of surrounding biological tissues, in measuring the magnetic susceptibility response of a region of interest in a patient, to detect the presence of ferromagnetic foreign bodies. The magnetic response of the surrounding tissues is rejected by defining a statistically determined normal range of magnetic susceptibility responses, or by rejecting magnetic field responses characteristic of materials with isotropic magnetization properties.

Abstract: A probe instrument using room-temperature sensor(s) that can measure variations in magnetic susceptibilities. The instrument has sufficient resolution to monitor paramagnetic materials in a human body, such as iron in a human liver, by noninvasively examining patients with iron-overload diseases. The instrument includes room temperature magnetic sensors, and detects the sample, that is, the tissue response to an alternating current field applied by an applied field coil. The applied field coil dimensions are chosen so that the applied field is optimized for maximum response from the liver while minimizing the effects due to the overlying abdominal tissue and at the same time not unduly increasing the sensitivity of the instrument to the lung. To overcome variations in the sensor output due to fluctuations in the applied field, change in the ambient temperature and mechanical relaxation of the instrument, the sensor-sample distance is modulated.

Abstract: A probe instrument using room-temperature sensor(s) that can measure magnetic susceptibilities variations. The instrument includes room temperature magnetic sensors, and detects the sample, that is the tissue response to an applied field coil. The sensors that can be used include magnetoresistive, fluxgate and magnetoinductive sensors. The applied field coil dimensions are chosen so that the applied field is optimized for maximum response from the item of interest while minimizing the effects due to the overlying tissue and at the same time not unduly increasing the sensitivity of the instrument to adjacent organs. To minimize noise introduced in the sensor due to fluctuations in the applied field, the applied field is canceled at the position of the sensor. To overcome variations in the sensor output due to fluctuations in the applied field, change in the ambient temperature and mechanical relaxation of the instrument, the detector assembly is oscillated while the examined patient remains stationary.

Abstract: A probe instrument using room-temperature sensor(s) that can measure magnetic susceptibilities variations. The instrument has sufficient resolution to monitor paramagnetic materials in a human body, and preferably iron in a human liver by noninvasively examining patients with iron-overload diseases. The instrument includes room temperature magnetic sensors, and detects the sample, that is the tissue response to an alternating current field applied by an applied field coil. The sensors that can be used include magnetoresistive, fluxgate and magnetoinductive sensors. The applied field coil dimensions are chosen so that the applied field is optimized for maximum response from the liver while minimizing the effects due to the overlying abdominal tissue and at the same time not unduly increasing the sensitivity of the instrument to the lung. To minimize noise introduced in the sensor due to fluctuations in the applied field, the applied field is canceled at the position of the sensor, i.e.

Abstract: A method and apparatus are disclosed for applying a low strength, time varying magnetic field to a selected screening region of a host, and for sensing a responsive magnetic field from a retained ferrous body within the screening region. The excitation field coil is designed to create a region of finite magnetic field within the screening region, and a region of near zero magnetic field. The sensors are placed within the region of near zero magnetic field to minimize the effect of the applied field. The effects of the applied field are further reduced by use of a reference sensor, field compensation coils, and a feedback loop. The magnetic gradient measured by the sensors is processed to locate and characterize the ferrous body.