 |
|
|
 |
|
|
Whole Body FDG- PET / CT
|
Abdominal Section: Note that the fusion of the black and white forms seen on CT with the color (metabolic activity seen on PET) reveals liver metastasis.
Whole body PET/CT is an emerging technology that combines positron emission tomography (PET) with computed radiographic imaging (CT) to put function and form on the same diagnostic page (PET/CT).
Spiral computed tomography CT can be performed to generate anatomic images of the entire body. When suspicious areas or tumors are found, CT allows your doctor to see their size, shape and internal radiographic density. Though computed radiographic tomography (and magnetic resonance imaging - MRI) are excellent methods to determine if an abnormality exists, its shape and location, it cannot reveal if the abnormality (e.g. tumor) is metabolically active.
Positron emission tomography (PET) is used to determine if tissues or tumors are metabolically active. This is important because, metabolically active tumors are more likely to be malignant. In the case of imaging of malignant melanoma, PET imaging can differentiate between benign cysts and metastatic tumors in the liver (and other sites). PET requires a small injection of radioactive material (e.g. FDG - glucose) that is preferentially absorbed by malignant tumors. It is important to note that any glucose absorbing process (inflammations, infections, working muscles and excretory systems) will also concentrate glucose and appear as a "hot-spot" on PET. It is the addition of the anatomic information provided by CT, that allows the physician to differentiate between benign and malignant tumors.
Dr. Finger has shown the though the liver is the most common initial site of metastatic choroidal melanoma. It can occur in the bones (in 50% of cases). Clearly, a whole-body PET/CT scan from the top of the head to the bottom of the feet will include all the bones in the body. It is important to realized that not all metastases will "light-up" with PET and that sometimes a dedicated CT or MRI will offer better anatomic imaging. So don't be surprised if there is suspicious area seen on PET/CT, your doctor may request an additional radiographic examination.
We expect more melanoma specific radioactive materials (other than FDG) to be used for PET/CT. This will improve the specificity and sensitivity of this test. To see the research work being conducted thus far, visit the links below.
Related Links
An article on the use of PET/CT SUV as a biomarker for the risk of metastasis from choroidal melanoma
The use of PET/CT for initial staging of choroidal melanoma
The use of PET/CT to evaluate intraocular choroidal melanoma
The use of PET/CT for patients suspected to have metastatic choroidal melanoma
|
|
 |
| While this WWW site is intended to provide general information as a public service, the content is not intended to represent official policies and practices of the institution or to substitute for health care provided by a clinician. Content and design copyright © Paul T. Finger, MD 1998-2010. ALL RIGHTS RESERVED •115 East 61st Street • New York City, New York 10021 • (212) 832-8170 |
|