Radiologists have used PET/CT technology for more than a decade to help referring physicians diagnose and monitor many types of cancer. Recently, local PET/CT capabilities at Medical Imaging of Fredericksburg, a partnership between Mary Washington Healthcare and Radiologic Associates of Fredericksburg (RAF), expanded significantly to include testing for metastatic bone disease and additional cancers, noted Neil B. Green, MD, physician director of nuclear medicine and PET/CT imaging for RAF. More specific testing for Alzheimer’s and other neurological conditions should begin within the next year, he added.
Dr. Green is one of seven RAF radiologists who are specially trained in interpreting PET/CT images. They evaluate tests 24/7 that are produced daily by the PET/CT system at Medical Imaging of Fredericksburg, adjacent to Mary Washington Hospital. The PET/CT system serves patients referred by area medical oncologists, surgical oncologists, pulmonologists, general surgeons, gastroenterologists, neurologists, otolaryngologists, and other physicians.
Images of the body of a patient with newly diagnosed breast cancer. PET/CT image on right shows spots in the chest and lumbar spine where the radio-labeled tracer has accumulated, indicating that cancer has spread to these structures.
PET, shorthand for positron emission tomography, maps the biochemical processes within the body. CT, or computed tomography, produces anatomical images. Combined, PET/CT delivers a detailed look inside the patient.
“For example, with conventional testing, such as a CT alone, you can assess the size and shape of a lymph node and try to determine if it is cancerous based on that,” Dr. Green explained. “With PET, you can inject the patient with a radio- labeled sugar and, if the lymph node absorbs that sugar at a level distinctive in cancer, you can be pretty sure it is a malignant process.” PET/CT also enables physicians to detect the spread of cancer and effectiveness of treatments.
Charles L. Maurer, MD, an oncologist with Hematology Oncology Associates of Fredericksburg, said, “I tell patients we use PET/CT like a night vision tool that looks for cancer. It shows areas of bright spots or hot spots where cancer may be. It can be a valuable tool when determining the correct therapy for particular cancers, and for staging of certain cancers. PET can also be used for interim staging when determining a patient’s response to treatment.”
For example, Dr. Maurer finds PET/CT helpful during the initial staging of lung cancers and colorectal cancers, initial staging and restaging of lymphomas (both Hodgkin’s and non- Hodgkin’s) after treatment, and intermittently for staging of breast cancers.
Many cancers, including lung cancer, colorectal cancer, breast cancer, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, esophageal cancer, and melanoma, absorb radio-labeled sugar in a distinctive way. The most commonly used radio-labeled tracer is fluorodeoxyglucose, or 18-FDG. Dr. Green said RAF radiologists also plan to offer PET/CT testing with additional radio-labeled tracers besides 18-FDG within the next year specific for neurological applications, including a more specific detection of Alzheimer’s disease than currently exists.
In February, sodium 18-fluoride (NaF) was approved for clinical applications in bone metabolism studies. Dr. Green said RAF radiologists are using NaF as an effective radio tracer for detecting metastatic disease to the bone and certain types of cancers that do not absorb sugar, such as prostate cancer and some breast cancers. PET/CT has advantages over conventional bone scans in appropriate cases.
“When evaluating metastatic disease to the bone, NaF PET is superior to plain nuclear medicine bone scans because the images are higher quality, which allows early and more thorough identification of bone metastases,” Dr. Green said.
For more information about PET/CT medical imaging studies, contact Neil B. Green, MD,
at green@rafimaging.com, contact the PET center directly at (540) 741-4PET, or visit
www.rafimaging.com.
Pictured above is Joseph Ackerman, PET/CT technologist, begins a PET/CT test at Medical Imaging of Fredericksburg.