In recent years, the technology available to help physicians detect and diagnose cancer has changed dramatically. More than half of the clinical imaging tools used by Siteman Cancer Center clinicians to take images or pictures of tumors and cancer cells had not been fully developed or did not exist 35 years ago. These advances now help doctors detect cancers earlier and more precisely.
At Siteman, we draw our clinical expertise in diagnostic imaging from the acclaimed Mallinckrodt Institute of Radiology (MIR) at Washington University School of Medicine, an international leader in the imaging of cancer and other diseases and disorders. MIR offers the latest imaging tools for cancer, including the following:
Positron emission tomography (PET): Developed by MIR researchers in 1972, PET captures tumor cells in action. It is widely used to evaluate patients with various cancers, including esophageal cancer, lung cancer and colorectal cancer. It accurately gauges the severity and spread of cancer by revealing the metabolic activity of tissues using small amounts of a radioactive compound. In some cases, PET imaging gives radiologists a way to detect cancer in early, more treatable stages – sometimes months before a tumor becomes evident through other forms of diagnostic testing.
Single photon emission computed tomography (SPECT): This technique, which resembles PET, is used at MIR to determine whether tumor cells in women with breast cancer have an abundance of the protein p-glycoprotein. Women whose tumor cells are covered with this protein may be poor candidates for chemotherapy. Knowing this allows doctors to switch to other forms of treatment.
Computed tomography (CT): An X-ray procedure that uses a computer to produce a detailed image of a cross-section of the body. CT images help verify the presence of kidney and pancreatic cancer, among others.
- Spiral CT: This technique is being used at MIR to detect colorectal polyps, which are precancerous growths of the colon. MIR radiologists scan patients with the spiral CT, which produces two-dimensional colonography images. These images are then transferred to a specialized computer workstation, where a 3-D rendering of the torso is created.
- Magnetic resonance imaging (MRI): Because of the sharp detail it provides, MRI is a mainstay for viewing the complex anatomy of the brain and detecting tumors there and in other internal organs. This noninvasive procedure also provides a frame of reference for techniques such as functional MRI (fMRI), which highlights active brain regions. Additional uses of MRI that may influence future cancer care include high-resolution BOLD venography (HRBV), which may provide a way to measure tumor growth by visualizing how many veins a tumor has to carry away its waste products.
Ultrasound: This technique uses sound waves to detect and characterize tumors, especially those of the liver, kidney, pancreas and reproductive organs. Echoes reflected off normal and abnormal tissues are captured by a computer to create two-dimensional images. Radiologists interpret these images to determine whether a mass is a solid tumor or a benign, fluid-filled cyst. Specialists also use ultrasound to guide the placement of needles during biopsies of tumors in the breast, liver and many other organs and for guidance in the placement of radioactive pellets during prostate cancer treatment.
Endoscopic ultrasound: A variation of ultrasound, endoscopic ultrasound involves the use of a probe on the end of a fiber-optic endoscope to look at intestinal abnormalities. It allows physicians to differentiate between tumors, cysts and stones in the bile duct, pancreas and other abdominal organs. Endoscopic ultrasound also can visualize rectal tumors and determine whether they have spread.
Even as current imaging tools prove their value in cancer care, MIR investigators are considering enhancements for the future. Already, a team of neurosurgeons, radiologists and radiation oncologists is successfully treating certain brain tumors using composites developed from MRI and CT scans. Composites of MRI and CT also are being used for 3-D radiation therapy of other cancers.
Eventually, imaging machines will perform multiple types of scans or readily trade scan information. Additional imaging compounds that can highlight unique characteristics of tumors also are being developed. These and other advances will help even more patients in their battles against cancer.