摘要:
A positioner for centering or otherwise situating medical devices such as biopsy needles with respect to a human body includes a clamp for receiving a portion of the human body (e.g., a breast), a carriage which moves along a carriage path next to the clamp, and a positioning arm pivotally mounted to the carriage and having a mount for a medical device thereon. The carriage may therefore carry the positioning arm along the carriage path to a desired location adjacent to the clamp, at which point the positioning arm may be pivoted to situate a medical device within the device mount at a desired location adjacent the portion of the body within the clamp. The components of the positioner are preferably made of materials that do not interfere with medical imaging instrumentation (e.g., MRI scanners), though the positioner may include markers at desired locations (e.g., on the positioning arm adjacent the device mount) which are visible by the imaging instrumentation so that the location of the medical device may be ascertained during imaging.
摘要:
Differential X-ray images are produced in order to improve the visibility of a contrast medium, such as iodine or xenon, having a K absorption edge at a predetermined X-ray energy. Such differential images are produced by combining first, second and third X-ray images which are individually produced by using first, second and third X-ray spectra at first, second and third X-ray energy levels. The first energy level is below the K edge energy, while the second energy level is above the K edge energy. The third energy level is above the second energy level. The second X-ray image is combined subtractively with the average of the first and third X-ray images to produce a differential X-ray image in which any image elements due to soft tissue and bone are largely cancelled out, while image elements due to the contrast medium are enhanced. In one preferred method, two versions of the second image are combined additively, and the first and third images are combined subtractively therewith. The first, second and third X-ray spectra may be produced by using a single X-ray source with first, second and third X-ray filters. When the contrast medium is iodine, such filters may contain iodine, cerium and lead, respectively. The X-ray source is preferably operated with first, second and third anode voltages when the first, second and third filters are used. The intensity level of the X-ray source may also be changed to provide three different intensity levels for the three different filters. The three X-ray images are preferably converted into television images which are combined electronically to produce the differential X-ray images. Three different gain levels may be employed in the television system for the three filters. The television system may include first and second image storage tubes to provide two stages of image subtraction. The first storage tube may be arranged to produce the differences between successive images in a four image system, in which two versions of the second X-ray image are used alternately with the first and third images. The difference signals produced by the first tube are then selectively written positively or negatively on the second tube in such a manner as to enhance and integrate the image elements due to the contrast medium, while largely cancelling out the image elements due to the soft tissue and bone.In the television system, it is highly advantageous to provide logarithmic video amplification, so that except for constant terms the video images will be proportional to the absorption coefficients. With such logarithmic amplification, the greatest degree of cancellation of the image elements due to bone and soft tissue is achieved.
摘要:
A system and apparatus is disclosed for providing percutaneous images to assist in performing an accurate tissue biopsy and to locate nuclear medicine tracer uptake within a living being. The invention provides superimposed, simultaneous ultrasound and nuclear activity images to assist in performing accurate tissue biopsy for any procedure in which nuclear activity is used to localize possible pathological tissue. The apparatus includes a medical instrument having at least a pair of radionuclide detectors capable of detecting the depth of tracer uptake within a region of interest, which can include locating the sentinel lymph node in a breast cancer patient. The radionuclide detector is coupled to, and in operable association with, an ultrasound probe for percutaneous detection of anatomical structure about the area of maximum tracer uptake. The radionuclide detectors and the ultrasound probe are pivotally connected. The depth of the maximum tracer uptake can be determined by pivotally moving the radionuclide detectors to vary a focal point which is formed by the intersection of a line of sight from each radionuclide detector. The focal point is adjusted to the area of maximum tracer uptake by use of a visual display of radioactivity count rate or an auditory output of the radioactivity count rate. After the depth is determined and mapped, an ultrasound image is produced of the localized area. The system produces an image in which the ultrasound image is superimposed with a color representation of the tracer uptake to assist a radiologist or a surgeon in performing a tissue biopsy while avoiding vital structure.