NMT » Case Studies » Current Case

Restaging Head and Neck Cancer with FDG
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View Image 2


Denise Wickstrom
Senior Student NMT
Medical College of Georgia

Laura Norman, CNMT
MCG Healthcare, Inc.
PET/CT Center

Hadyn Williams, MD
Chief of Nuclear Medicine and Positron Imaging
Medical College of Georgia, School of Medicine

Mary Anne Owen, MHE, RT(N)
Assistant Professor, Nuclear Medicine Technology
Department of Biomedical and Radiological Technologies
Medical College of Georgia



Discussion (click to view)

2-D versus 3-D

Septa is inter-slice ring collimation. Septa rings are made of lead. 2-D acquisition means that the septa
are in and limit’s the angle in which photons can be detected. This type of acquisition detects all direct
rays and limited cross rays. This limits counts which also limits scatter. 3-D acquisition means that the
septa are out. This collects all direct rays and cross rays (everything). There is a higher count rate usually
4-6 times higher this count rate is to high for BGO crystal. This also means that there is a lot more scatter
acquired. 3-D acquisition requires a longer processing time. 2-D is better for whole-body imaging, whereas
3-D is good for brain imaging.

Instructor's Comment:
Q: Why does 3-D work for brains and not for whole body PET?
Q: How are these affected by attenuation correction?



Patient History


This patient is 46 year old black male. Laryngectomy for squamous cell approximately 10 years ago.

Instructor's Comment:
Q: What are the pathological characteristics of “squamous cell”?

He now has a right thigh mass.



Radiopharmacy


8.97 mCi of F18 FDG were injected intravenously and the patient then rested quietly (to avoid muscle uptake) in a room alone for 50 minutes.



Procedure


At 50 minutes the patient was asked to empty his bladder before positioning on the scanner. This helps to eliminate artifacts caused by the bladder with FDG excretion.



Patient Preparation


Instructor's Comment:

Q: Was there any requirement for patient preparation?
Q: What about glucose level?
Q: What considerations for preparing for patient arrival to assure a successful procedure?
Q: What are the considerations for reimbursement of PET/CT in head and neck carcinoma?



Positioning


The patient is placed on the table supine. The first image is the head and neck, this is imaged with the patients arms down. The second image is from the neck to the lower extremities.



Camera


Phillips (ADAC) Gemini (PET (GSO)/CT)



Prior Studies


A right thigh mass was found on a MRI. The biopsy of the mass in the right inner thigh reportedly showed squamous cell carcinoma.



Findings (from report)


There are widespread extensive sites of intense abnormal activity seen involving a submental nodule, extensively in multiple lesions in the mid and upper right lung parenchyma extending to the pleura, extensively throughout the mediastinum and bilateral lung hila, multiple mid and lower lung parenchyma nodules bilaterally, multiple sites in the upper anterolateral right chest wall, multiple subcutaneous nodules in the thorax, abdomen, pelvis, and throughout both lower extremities, more intense and numerous in the right calf, extensively in the retroperitneum of the upper and mid abdomen, multiple sites in the pelvis external iliac lymph nodes bilaterally and in lymph nodes in the lower pelvis, and in a mid left rib laterally and two sites in the right scapula. The large lesion in the medial proximal right thigh shows intense uptake peripherally with a cool central region suggesting necrosis. There are focal areas of abnormal bone uptake in the patellae bilaterally, both proximal tibias, both distal fibulas at the lateral malleoli, and right calcareous.

There are very extensive and widespread areas of abnormal uptake consistent with widely metastatic squamous cell carcinoma in the submental region, thorax, abdomen, pelvis, multiple subcutaneous nodules in the torso and lower extremities, and bone in the right scapula, left rib and lower extremities. It is conceivable that systemic granulomatous disease such as systemic acidosis could conceivably produce this appearance; this is considered relatively less likely and there is reportedly biopsy-proven metastasis in the inner right thigh mass from squamous cell carcinoma.



References


Nuclear Medicine Review Manual, Williams, S. M.D.