Making Possible New Advanced Diagnostic Approaches Medical Imaging

Noninvasive diagnostic imaging systems capable of producing tomograms or 3-D images of a patient's organs are playing an essential role on the health-care front.
Canon is creating new value in advanced medicine with proprietary imaging technologies accumulated over the years. Important fields of R&D include an adaptive optics (AO) scanning laser ophthalmoscope (SLO) for precisely examining the progression of eye disease and reliably verifying the medical treatments administered. An additional area of importance is a photoacoustic mammography system for promptly and accurately detecting breast cancer without exposing subjects to radiation or pain. Canon's technologies will contribute to a crucial mission by providing assistance with outstanding medical imaging devices for improved communications and healthier daily living for everyone in the medical sector.

Adaptive Optics Scanning Laser Ophthalmoscope

Examining the Retina at the Cellular Level

Visualizing Individual Photoreceptors and the Movement of White Blood Cells

Image Captured with AO-SLO

Canon's medical imaging technologies in the field of ophthalmology are also being applied in new testing apparatus. The adaptive optics scanning laser ophthalmoscope (AO-SLO) being developed in collaboration with Kyoto University is expected to enhance the value of the retinal examination, a procedure essential for the diagnosis of eye diseases.

Retinopathy and other disorders of the eye can develop as a result of not only hereditary transmission and aging, but also diseases such as diabetes or other causes. Because eye disorder can cause reduced visual acuity or loss of sight, early disease detection is essential for healthy eyes, just as it is for other parts of the body.

Among the many organs of the body, the fundus of the eye is the only organ with a vasculature clearly viewable by direct observation. Retinal examinations reveal not only vascular conditions associated with eye disorders, but possibly also how hypertension, arterial sclerosis, and other diseases affect the eye.

The early detection of abnormalities in the retina requires an ophthalmoscope that can identify photoreceptors. Canon imaging technologies, as represented by the optical and image-processing technologies in which the company excels, now enable the viewing of minutely detailed dynamic images with a resolution of around 5 µm (microns). This has made possible the detailed observation of individual photoreceptors as well as the white blood cells flowing in the blood vessels of the retina. Next generation of ophthalmological devices that medical professionals are eagerly awaiting will arrive soon.

Imaging Technologies to Facilitate Early Detection of Eye Disorders and Other Diseases

AO-SLO technology can be divided into three basic parts: an ophthalmoscope system configured with a laser, mirror and lenses; an AO control system with a wavefront sensor and wavefront correction device; and an image analysis system for analyzing captured images of the retina.

Several large hurdles must be cleared before high-definition images of the photoreceptors can be reliably captured. One of these is ocular aberrations. Aberration refers to the blurring or distortion of an image while the image is being formed through a lens system. Because the eye, as a lens, has aberrations, when observing the eye from the outside using an ophthalmoscope, distortions invariably occur in the resulting images. Aberrations of the human eye vary from person to person and also according to the condition of the eye during examination. Adaptive optics (AO) is an advanced technology that enables precise correction for aberrations. Canon has developed an AO control system that measures aberrations using a sensor and controls a wavefront correction device to make possible high-speed correction, and integrated the system into the scanning laser ophthalmoscope (SLO).

Canon is also developing a system for analyzing the images captured by the AO-SLO. This system detects and corrects for any blurring or distortion of dynamic images of photoreceptors and capillary vessels caused by movement of the patient's eye during recording, supporting the analyzing and counting of photoreceptors and the analyzing of blood flow to determine the velocity through the capillary vessels.

The current system is at the prototype stage as a collaborative project between Canon and a number of universities and medical research institutes in Japan and abroad.
A growing number of scientific presentations in international conferences have demonstrated the usefulness of AO-SLO for imaging diagnosis by identifying correlations between the analytical results of AO-SLO-captured images and disease states. Through a growing body of clinical evaluations, Canon is making progress toward the adoption of AO-SLO in clinical settings and aims to contribute to the early detection of eye disorders and other diseases.

Schematic Overview of AO-SLO

Photoacoustic Mammography

Identifying the State of Cancer Cells by Exposing Blood Vessels to Light

Visualizing the State of Angiogenesis Associated with Cancer Using Ultrasound and Light

Conceptual Overview of the Photoacoustic Imaging System

Canon makes full use of the technologies the company has cultivated to enable the earlier detection of breast cancer and contribute to improved qualitative cancer diagnosis, applying its expertise to leading-edge diagnostic imaging of mammary glands.
If breast cancer is detected early, the chances are high that it can be treated successfully. Many types of cancer cells form new blood vessels around tumorous tissue that supply nutrition. A technology to visualize the new blood vessels feeding a cancer would facilitate the early detection of cancer and enhance the accuracy of diagnosis of the cancer state.

In its studies focused on cancer properties, Canon is working with Kyoto University to develop a photoacoustic mammography technique for visualizing new blood vessels using laser radiation and ultrasonic waves.
When tissue under observation is exposed to near-infrared light (pulse laser), the hemoglobin within the blood absorbs the light energy and expands due to heat. As this happens, the tissue emits weak ultrasonic waves. Canon's new mammography process visualizes the condition of angiogenesis in a cancer by detecting ultrasonic waves with sensors and reconstructing 3-D images from the detected data.
A rapidly growing cancer tissue will generally have lower oxygen concentration than the surrounding normal tissues. Thus, the blood flowing through a cancer tissue is also expected to show a lower oxygen concentration. If this is so, it may be possible to estimate whether a tumor involving metabolism is benign or malignant by measuring the oxygen saturation of hemoglobin in the blood around the tumor with laser beams of multiple wavelengths.

Canon Imaging Technologies for Cutting-Edge Medical Treatments

Canon has just built a prototype and supplied it to physicians at the Graduate School of Medicine of Kyoto University as a tool for clinical evaluations to explore the usefulness of photoacoustic mammography.

If realized, photoacoustic mammography would make up for two shortcomings of the conventional X-ray mammography modality widely used for routine breast cancer examinations: ionizing radiation exposure and difficulty in visualizing microcalcified lesions of the dense breast. The technology is also expected to prove beneficial in evaluating the early effects of chemotherapy by providing data on specific properties of breast cancer, including the hemoglobin oxygen saturation of the blood.

Canon strives to support health care practitioners working in the vanguard of cancer treatment, as well as patients and their families through its strengths in optical technologies,and image-processing technologies, and development of breakthrough innovative medical systems to contribute to advanced medicine.