US-12625283-B2 - Dual gamma ray and visible light imaging device

US12625283B2US 12625283 B2US12625283 B2US 12625283B2US-12625283-B2

Abstract

A medical imaging device for use in imaging a subject using both gamma rays and light rays emanating from the subject, the device comprising: separation means to separate gamma rays and light rays emanating from the subject into a gamma ray channel comprising gamma rays and a light ray channel comprising light rays; first sensor means arranged to receive and detect gamma rays from the gamma ray channel and to generate first signals for use in forming a first image of the subject; second sensor means arranged to receive and detect light rays from the light ray channel and to generate second signals for use in forming a second image of the subject; wherein the first sensor means and the second sensor means are arranged to receive gamma rays and light rays, respectively, which propagate from the subject upon substantially coincident paths.

Inventors

Andrew Victor Polijanczuk
George William WYLDE
Matthew Robert HICKEY
Paul Andrew CLOAD
Mark Joseph ROSSER

Assignees

SERAC IMAGING SYSTEMS LTD

Dates

Publication Date: 20260512
Application Date: 20220128
Priority Date: 20210129

Claims (19)

1 . A medical imaging device for use in imaging a subject using both gamma rays and light rays emanating from the subject, the device comprising: separation means to separate gamma rays and light rays emanating from the subject into a gamma ray channel comprising gamma rays and a light ray channel comprising light rays; first sensor means arranged to receive and detect gamma rays from the gamma ray channel and to generate first signals for use in forming a first image of the subject; second sensor means arranged to receive and detect light rays from the light ray channel and to generate second signals for use in forming a second image of the subject; wherein the first sensor means and the second sensor means are arranged to receive gamma rays and light rays, respectively, which propagate from the subject upon substantially coincident paths.
2 . The device according to claim 1 , wherein the separation means comprises a mirror arranged at substantially 45 degrees to gamma and light rays propagating from the subject.
3 . The device according to claim 1 , wherein the first sensor means is housed in a chamber substantially opaque to gamma rays, the chamber comprising a window arranged to receive gamma rays from the gamma ray channel, and wherein the window is substantially transparent to gamma rays.
4 . The device according to claim 3 , wherein the chamber comprises a tapered end, the tapered end tapering towards the window.
5 . The device according to claim 3 , wherein the window comprises, or is comprised of, a pinhole.
6 . The device according to claim 3 , wherein the chamber comprises a movable member comprising two or more movable windows of different sizes and/or shapes, wherein the movable member is reversibly movable such that at least one of the movable windows of different size and/or shape is arranged to form the window in the chamber.
7 . The device according to claim 1 , wherein the first sensor means comprises a gamma ray scintillator means responsive to gamma rays and which produces scintillator output flashes of light in response to incidences of gamma rays.
8 . The device according to claim 7 , wherein the gamma ray scintillator is deposited on the surface of a Fibre Optic Plate (FOP).
9 . The device according to claim 8 wherein the Fibre Optic Plate (FOP) is a tapered Fibre Optic Plate (tFOP).
10 . The device according to claim 9 wherein the optical fibre sizes of the tFOP output surface and the plate/surface it is to be optically coupled with, or in contact with, are in a ratio of approximately between approximately 10:1 to approximately 1:10.
11 . The device according to claim 10 wherein the ratio is approximately 2:1 or 1:2.
12 . The device according to claim 7 , wherein the first sensor means comprises first signal digitisation means to convert scintillator output flashes, or intensified scintillator output flashes, into first signals for use in forming a first image of the subject.
13 . The device according to claim 12 , wherein the first signal digitisation means comprises a complementary metal-oxide-semiconductor (CMOS) detector or charge coupled device (CCD).
14 . The device according to claim 1 , wherein the first sensor means comprises a multiplication unit to concentrate and/or intensify the scintillator output flashes produced by the gamma ray scintillator means.
15 . The device according to claim 14 , wherein the multiplication unit comprises a concentration means to concentrate the scintillator output flashes, and wherein the concentration means comprises a tapered fibre optic plate (tFOP) comprising an tFOP input surface to receive the scintillator output flashes and a tFOP output surface to output demagnified output flashes, wherein the surface area of the tFOP input surface is larger than the surface area of the tFOP output surface.
16 . The device according to claim 14 , wherein the multiplication unit comprises an intensification unit to intensify the scintillator output flashes produced by the gamma ray scintillator means.
17 . The device according to claim 1 , wherein device is powered via a power-over-ethernet (PoE) cable.
18 . A system comprising one or more devices according to claim 1 , and together with one or more of a: display; display monitor, support stand/frame, movable arm, power supply, battery, memory, Wi-Fi capability, Bluetooth capability, communication interface, and communication cables.
19 . A method of imaging a subject using a device according to claim 1 , the method comprising: permitting both gamma rays and light rays emanating from the subject to be communicated to the separation means, the separation means arranged to separate the gamma rays and light rays emanating from the subject into a light ray channel comprising light rays and a gamma ray channel comprising gamma rays; the first sensor means is arranged to receive and detect the gamma rays from the gamma ray channel and to generate first signals for use in forming a first image of the subject; the second sensor means is arranged to receive and detect the light rays from the light ray channel and to generate second signals for use in forming a second image of the subject; forming a first image of the subject from the first signals; forming a second image of the subject from the second signals; and displaying the first image and second image.

Description

FIELD OF THE INVENTION This invention relates to an imaging device. In particular, though not exclusively, the invention relates to a medical imaging device using both gamma rays and light rays emanating from the subject, as well as methods of using the same. BACKGROUND OF THE INVENTION A gamma camera (also called γ-camera or scintillation camera), is a device used in medical imaging to image gamma radiation being emitted from radioisotopes. As such, the device must be suitable for the levels of gamma radiation given off by radio isotopes administered to a subject, while providing suitable resolution to allow a medical practitioner to perform medical treatment, analysis or diagnosis etc. Therefore, gamma medical imaging devices have a sensitivity and resolution that are tailored to their role. Typically the device is required to form medical images of radioisotopes with a gamma emission energy between about 35 keV and about 511 keV administered to a subject at levels between about 10 MBq and 1000 MBq for a 70 kg body weight. The dose may be adjusted to take account of the size of the subject. Gamma cameras are commonly used to create two dimensional images in a technique known as scintigraphy. In scintigraphy radioisotopes are commonly attached to tracer agents or drugs (radiopharmaceuticals) which travel to specific organs or tissues, and in that way those target tissues can be imaged. So, this technique can create visual representations of the interior of the target for clinical analysis and medical intervention, as well as visual representation of the function of organs or tissues. Therefore, this technique goes beyond revealing internal structures hidden by the exterior of the subject, it can target certain organs or diseased states and/or provide more information about their anatomy and function. Many gamma cameras are large, expensive and fixed, and so are typically housed in a bespoke room in a hospital. Patients are typically required to go to the location and are inserted into the body of the device to be scanned. Smaller gamma cameras with a more limited field of view are more portable but remain relatively large and unwieldy, and further maybe lacking in sensitivity and/or resolution and/or suitable field of view. Some portable cameras are known to be quite inefficient and their power use may result in overheating, which can limit the camera's usefulness in the field. Examples of gamma cameras used in scintigraphy include in Siemens Healthineers' Symbia Intevo Excel, Oncovision's Sentinella and Digirad's Ergo™ Imaging System. In addition, attempts have been made to align the gamma ray images with normal visible (optical) images of the subject. In that way the source of the gamma radiation within the body of the subject can be correlated with an external surface of the subject. This is typically done by using a gamma camera and a visible camera to image the subject at the same time. However, there is difficulty obtaining good alignment of the gamma and optical ray images due to the phenomena of parallax (schematic representation shown in FIG. 1), i.e. a displacement in the apparent position of an object viewed along two different lines of sight by the optical camera and the gamma camera. See also U.S. Pat. No. 7,173,251, US 2008/024290 and Physica Medica 30 (2014) 331 to 339, Bugby et al. While this discloses a portable device, this device suffers from a number of limitations and drawbacks. It requires the manual adjustment and calibration of the gamma and optical field of view during construction of each unit, a time consuming process. The scintillator and substrate is manually mounted on the EMCCD sensor and secured with tape. The EMCCD detector requires active cooling and must be kept at below 0° C. during operation, to minimise electronic noise that degrades image quality. Heat removed from the EMCCD is absorbed by a phase change material that has a finite capacity to keep the sensor at the desired temperature. As such, maintaining the sensor at the required temperature during continuous operation is not possible. Moreover, the sensor must be kept in a high vacuum chamber to avoid condensation on the sensor when at these low temperatures. Again this is difficult, and takes some hours of time during assembly and requires a design capable of maintaining high vacuum for years of product life time. This design contains a separate electronics box for control and data processing prior to transfer to a computer for offline image reconstruction and display, which is slow and not convenient. The device requires multiple cables to supply power and transfer data signals from the gamma and optical sensors with separate communication channels (cables) for the gamma and optical images. There remains a need in the art for improved solutions to the problem of gamma ray imaging. SUMMARY OF THE INVENTION Herein disclosed, is a device for use in imaging a subject using both gamma rays and light rays emanating fr