By the end 2015, well over 1.5 million new cases of cancer will be diagnosed in the United States alone and over half of these cases will result in death. The demand for more advanced tumor detection techniques and treatments, therefore, has become more dire than ever. Currently, technological developments for tumor detection, staging, and treatment evaluation include ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon-emission computed tomography. While these powerful imaging techniques exist to detect the tumor, it still remains that the greatest barrier to surgical tumor resection is the difficulty in discerning between tumor and normal tissue to create a tumor-free margin.
By the end 2015, well over 1.5 million new cases of cancer will be diagnosed in the United States alone and over half of these cases will result in death. The demand for more advanced tumor detection techniques and treatments, therefore, has become more dire than ever.
Without proper visualization, a clear field of the tumor cannot be seen during surgery. Surgical microscopes are highly specialized scopes installed on an articulated mount which provides a long working distance and functional enhancements. In current “white-light” reflectance, where light is shone on the damaged tissue and reflected back into a surgical microscope, the surgeon has very low sensitivity for identifying malignant cells and thus is unable to easily remove all of the cancerous tissue. The primary treatment for most solid cancer is surgery and complete removal of all malignant cells. This procedure can cure the patient of that cancer, but the process is not perfect. For example, brain tumor tissue can be hard to distinguish from healthy brain tissue during surgery. Neurosurgeons use their best judgment in the operating room but often must guess exactly where the edges of the tumor are when removing it. New advancements in surgical microscopy and fluorescence imaging would allow for improved visualization of tumor extent, allowing the surgeon to view cancer cells that they might have missed using white-light reflectance. In the context of cancer surgery, the ability to accurately visualize tumor cells at the molecular level at both primary and metastatic sites will improve diagnostic accuracy, reduce unnecessary surgery, and improve completeness of resection.
Rather than displaying a 2D image of the tissue which lacks the spatial relationships that would help a surgeon identify anatomical points of reference, this new augmented microscopy presents a simultaneous view of real objects in the surgical field and computer-processed three-dimensional image superimposed in real time.
Researchers at the University of Arizona are in the process of developing new microscopic technology that utilizes this type of fluorescence imaging to assist in the accuracy of surgical procedures. This new technology, called augmented microscopy, overlays images of tissue dyed with fluorescent solution depicting diagnostic information such as blood flow and cancerous tissue over real images of blood vessels and other tissues and structures being viewed with the microscope. Rather than displaying a 2D image of the tissue which lacks the spatial relationships that would help a surgeon identify anatomical points of reference, this new augmented microscopy presents a simultaneous view of real objects in the surgical field and computer-processed three-dimensional image superimposed in real time. Brian Pogue, a professor of engineering sciences at Dartmouth college, stated, “Surgeons want to see the molecular signals with their eyes, so that they can feel confident about what is there. Too often, what they see is a report of the signals depicted in false color on a monitor. By displaying information through the surgical scope itself, the surgeon then sees the information with his or her own eyes.” In the past, surgeons aggressively removing brain tumors were at great risk of damaging normal tissue, impairing the patient’s’ brain function. However, incomplete removal of all the cancerous cells would result in almost guaranteed relapse. Surgical resection of tumors therefore represents a delicate balance between effective removal of cancerous tissue and minimization of damage to healthy tissue. Being able to simultaneously see the surgical field in direct contrast with the overlaid images may allow surgeons to remove tumors more accurately and with minimal collateral damage . Similar studies exploring similar concepts of advancements in fluorescence imaging have been conducted in research universities such as the University of Michigan. New laser-based microscopic technology, similar to augmented microscopy, will help surgeons see the difference between tumor tissue and normal tissue in real-time. This new development, “allows the surgical decision-making process to become data driven instead of relying on the surgeon’s best guess,” said Daniel Orringer, MD, the U-M neurosurgeon piloting the technology in collaboration with the Pathology Department at the University of Michigan Medical School.
Advances in surgical techniques and technology will continue to allow medical professionals to be readily equipped to address disease control and prevention.
Advances in surgical techniques and technology will continue to allow medical professionals to be readily equipped to address disease control and prevention. “This technology has the potential to resolve a long-standing issue in cancer surgery, which is the need for faster and more effective methods to assess whether a tumor has been fully removed,” said Richard Conroy, . director of the Division of Applied Science & Technology at the National Institute of Biomedical Imaging and Bioengineering at the NIH, which provided funding for the development of the technology. The advances being made in fluorescent imaging technologies promise leaps forward not only in improving patient safety and surgical outcomes, but also in reducing overall healthcare costs through increasing the success of initial surgeries, preventing further procedures. Technology like this is pending FDA approval, but with the hopeful implementation of these surgical procedures, development of a more successful avenue for tumor resection and cancer treatment is just on the horizon.
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