Case Author(s): Yungao Ding, M.D., Ph.D. and Tom R. Miller, M.D., Ph.D. , 03/15/2001 . Rating: #D., #Q.
Diagnosis: Oral administration of FDG in a patient with lung cancer
Brief history:
70-year-old man with newly diagnosed lung cancer, now being evaluated for staging.
Images:
Whole-body re-projection (volume rendered) PET image.
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View second image(pt).
Delayed re-projection PET image of the abdomen and pelvis
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CT of the chest
Full history/Diagnosis is available below
Diagnosis: Oral administration of FDG in a patient with lung cancer
Full history:
70-year-old man with newly diagnosed lung cancer was evaluated with FDG-PET for staging. The patient has a history of intravenous drug abuse, and no venous access was found for the administration of F-18 FDG.
Radiopharmaceutical:
15.0 mCi F-18 fluorodeoxyglucose (FDG) p.o.
Findings:
PET demonstrated a large mass with intense FDG uptake in the right hilum corresponding to the patient's known carcinoma. Peripheral to the large mass is a wedge-shaped area of mildly increased FDG uptake due to the adjacent post-obstructive pneumonitis as evidenced in the CT of the chest.
In addition, there is intense FDG activity in the abdomen and pelvis conforming to small bowel loops in the initial PET imaging. Further delayed PET imaging of the abdomen and pelvis showed progression of the FDG into the distal ileum, cecum and proximal ascending colon.
Mild FDG uptake in the left chest wall is of uncertain significance. This may be due to prior trauma, but there is no focal abnormality identified on CT in that region.
Discussion:
F-18 fluorodeoxyglucose (FDG) is normally administered intravenously. However, in patients with no venous access, FDG can also be administered orally, as in this case. Like glucose, FDG is rapidly absorbed after oral ingestion. This patient was initially imaged about 45 minutes after drinking FDG diluted in 200 ml water. There is a potential pitfall of obscuring abdominal and pelvic lesions by residual tracer activity in the bowel loops, but delayed imaging showing residual FDG progressing distally will help to further evaluate abdominal and pelvic structures. The oral route thus is best reserved for patients with tumors outside of the abdomen and pelvis.
Major teaching point(s):
If there is no venous access, F-18 FDG can be administered orally.
With oral ingestion of FDG, delayed imaging of the abdomen and pelvis will help to evaluate abdominal and pelvic structures if there is significant residual tracer activity in the bowel loops.
ACR Codes and Keywords:
References and General Discussion of PET Tumor Imaging Studies (Anatomic field:Lung, Mediastinum, and Pleura, Category:Neoplasm, Neoplastic-like condition)
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Case number: pt051
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