Utility of TL-201 SPECT in clarifying false-positive FDG-PET findings due to osteoradionecrosis in head and neck cancer.
BACKGROUND
This study aimed to determine whether Tl-201 single photon emission CT (SPECT) is potentially useful in differentiating false-positive fluorodeoxyglucose positron emission tomography (FDG-PET) findings caused by osteoradionecrosis (ORN) from recurrent head and neck cancer after radiotherapy.


METHODS
Five patients were recruited. Dual-phase FDG-PET and dual-phase Tl-201 SPECT were performed for each patient.


RESULTS
All 5 patients proved to have ORN without recurrent cancer. By visual interpretation, the results were 4 positive versus 1 negative for PET, and 4 negative versus 1 positive for Tl-201 SPECT. The Tl-201 SPECT clarified 3 of the 4 false-positive PETs to be ORN. Dual-phase semiquantitative studies showed decreased standardized uptake value (SUV) over time in 3 of the 4 false-positive PETs and decreased lesion/background ratio over time in the false-positive Tl-201 SPECT.


CONCLUSIONS
The Tl-201 SPECT may help clarify suspected false-positive FDG uptake caused by ORN. Dual-phase FDG-PET and dual-phase Tl-201 SPECT may also have some value.
Wang
Chih-Hsiu
CH
Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.
Liang
Ji-An
JA
Ding
Hueisch-Jy
HJ
Yang
Shih-Neng
SN
Yen
Kuo-Yang
KY
Sun
Shung-Shung
SS
Kao
Chia-Hung
CH
D000328:Adult; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D010025:Osteoradionecrosis / Q000000981:diagnostic imaging*; D010039:Otorhinolaryngologic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D019788:Fluorodeoxyglucose F18