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Clinical application of FDG-PET in head and neck cancer includes identification of metastases, unknown primary head and neck malignancy, or second primary carcinoma, and also recurrent tumor after treatment. In this study, the additional value of PET/CT fusion images over PET images alone was evaluated in patients with initial staging and follow up of head and neck malignancy.Forty patients with suspected primary head and neck malignancy and 129 patients with suspected relapse after treatment of head and neck malignancy were included. FDG-PET/CT study was performed after the intravenous administration of FDG (5 MBq/kg). Target of evaluation was set at primary tumor, cervical lymph node, and whole body. PET images and PET with CT fusion images were compared. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results of PET and PET/CT were compared with postoperative histopathological examination, and case by case comparison of PET and PET/CT results for each region was performed. The additional value of CT images over PET only images was assessed. Statistical differences in sensitivity and specificity were evaluated.In the comparative evaluation of 507 targets by PET alone and PET/CT, 401 targets showed agreement of the results. Of the 106 discordant targets, 103 showed a positive result on PET alone and negative result on PET/CT. These results showed a significant difference (p0.01). Sensitivity of PET/CT was slightly higher than that of PET without statistical significance, while specificity of PET/CT was significantly higher than that of PET alone (Initial staging: 90.5% vs. 62.2%, p0.01; Follow up: 97.2% vs. 74.4%, p0.01). In Fisher's direct probability test, a significant difference was noted in the sensitivity (Initial staging: 91.3% vs. 87.0%, p0.01; Follow up: 93.9% vs. 91.4%, p0.01).Combined PET/CT showed improved diagnostic performance than PET alone by decreasing the number of false positive findings in patients with initial staging and follow up of head and neck malignancy.

Objectives: To comparel-3-[18F]-fluoro-α-methyltyrosine (FMT)-positron emission tomography (PET) and 2-[18F]-fluoro-2-deoxy-d-glucose (FDG)-PET in the differential diagnosis of maxillofacial tumors.Methods: This study included 36 patients (16 males, 20 females; 31–90 years old) with untreated malignant tumors (34 squamous cell carcinoma, one mucoepidermoid carcinoma, one rhabdomyosarcoma) and seven patients (five males, two females; 32–81 years old) with benign lesions. In all patients, both FMT-PET and FDG-PET were performed within two weeks before biopsy or treatment of the lesions. To evaluate the diagnostic usefulness of FMT-PET and FDG-PET, visual interpretation and semiquantitative analysis were performed. PET images were rated according to the contrast of tumor uptake as compared with background, and were statistically analyzed. As a semiquantitative analysis, standardized uptake values (SUV) of the primary tumors were measured, and the SUV data were analyzed using receiver operating characteristic (ROC) curves.Results: The mean SUV of the malignant lesions were significantly higher than those of the benign lesions in both FMT-PET (2.62±1.58 vs. 1.20±0.30, p

L-3-[¹⁸F]-fluoro-α-methyl tyrosine (FAMT) is transported into cancer cells by L: -type amino acid transporter 1 (LAT1). The purpose of the present study is to correlate the uptake of FAMT and FDG with the cellular proliferative activity measured by the Ki-67 labeling index (Ki-67 LI) in oral squamous cell carcinoma (OSCC).Twenty-five patients with OSCC were enrolled in this study. Both FAMT-PET and FDG-PET were performed within 4 weeks before surgery in all cases. The uptake of FAMT and FDG was compared by semiquantitative analysis with maximal standardized uptake values (SUVmax) of the primary tumors. Ki-67 LI of the tumors was analyzed by immunohistochemical staining and correlated with the clinicopathologic variables and the uptake of PET tracers.For primary tumor detection, FAMT-PET exhibited a sensitivity of 84%, whereas that of FDG-PET was 88%. In all visible lesions, mean FDG uptake determined by average SUVmax was 9.7 (range 4.2-15.9) and mean FAMT uptake was 3.5 (range 1.3-8.5). The SUVmax of FAMT tended to show a better correlation with Ki-67 LI (r = 0.878) than that of FDG (r = 0.643).Uptake of FAMT correlated with cellular proliferation of OSCC. FAMT-PET may be a useful procedure to evaluate tumor proliferation of OSCC.

We experienced a case of unexpected ECG abnormality with hyperkalemia. A 65-year-old man was suffering from maxillary sinus cyst and Caldwell-Luc procedure was scheduled. He had diabetes mellitus and hypertension for 15 years, and was taking oral hypoglycemic agent and hypotensive drug (angiotensin converting enzyme and angiotensin receptor blockers : ARB). Abnormal findings were HbA1c 7.7% and glycosuria over 1,000 mg x dl(-1). ECG and other laboratory tests were within normal limits. The patient was monitored with 3 leads ECG during the operation. At one hour and 33 minutes after the start of operation, we detected sudden ECG changes consisting of wide QRS wave and peaked T wave. We consider hyperkalemia and checked blood potassium concentration three times. The results were 5.8, 6.3, 6.2 mmol x l(-1), respectively. We treated the patient with calcium gluconate injection, saline infusion, furosemide injection and glucose-insulin therapy. The ECG was normalized one hour and 23 minutes after the abnormal ECG finding and the potassium concentration decreased to 4.8 mmol x min(-1). After the operation, the potassium concentration and creatinine clearance were within normal limits. Hyperkalemia in this case might have been induced by diabetes mellitus, administration of ACEI and ARB, and hypovolemia.

Increased expression of glucose transporter-1 (Glut-1) and glucose transporter-3 (Glut-3) has been reported in many human cancers. The mechanism of glucose entry into oral squamous cell carcinoma (OSCC) remains unclear. In this study we investigated, in untreated human OSCC, the relationship between tumour fluorine-18 fluoro-2-deoxy-d-glucose (FDG) accumulation and the expression of Glut-1 and Glut-3, as well as the association between the expression of Glut-1 and of Glut-3. All patients underwent FDG positron emission tomography (PET) pre-operatively. Standardised uptake values (SUVs) were used for evaluation of tumour FDG uptake. Final diagnoses were established by histology. Immunohistochemical staining results were evaluated according to the percentage (%) of positive area, intensity and staining score. Tumour sections were stained by immunohistochemistry for Glut-1 and Glut-3. Glut-1 immunostaining revealed that 18 (94.7%) of the 19 tumours stained positively, while Glut-3 immunostaining yielded positive findings for 16 (84.2%) tumours. Overall, a relatively low level of agreement (36.8%) in the staining score was observed between Glut-1 and Glut-3 expression. No relationship was found between the staining pattern and tumour differentiation or T grade classification in either Glut-1 or Glut-3 immunostaining. Furthermore, no relationship was found between increased FDG SUV and tumour differentiation, but the former did correlate with T grade. In conclusion, high FDG uptake values were seen in OSCC with overexpression of Glut-1 and Glut-3. However, no significant correlation was found between FDG SUV and Glut-1 or Glut-3 expression.

Accurate detection of head and neck cancer is crucial in patients' quality of life. The head and neck area consists of many complicated anatomical structures. Conventional imaging procedures such as CT and MRI provide much detailed information, but accurate estimation of the spread of cancer is still limited. Positron emission tomography (PET) using 2-deoxy-2-[18F]fluoro-D-glucose (FDG) is clinically useful in detecting head and neck cancer, providing accurate estimates of head and neck primary cancer especially in cases that are equivocal on CT and/or MRI. FDG-PET is able to show metastatic lymph nodes that may appear normal on CT and/or MRI. Further, whole body FDG-PET makes it possible to detect distant metastases. The clinical usefulness of FDG-PET in head and neck cancer is discussed in this review.

Objective: The aim of this study is to clarify the clinical utility of 2-deoxy-2-[18F]fluoro-d-glucose (FDG) positron emission tomography (PET) in determining the TNM classification in patients with oral cancer.Methods: Twenty-five consecutive patients (14 male and 11 female; age range, 40 yr to 86 yr) with oral cancer were included in this study. The diagnostic accuracy for detecting cervical lymph nodes was investigated by comparing the results of CT and/or MRI and physical findings. For the semi-quantitative analysis, the tumor standardized uptake value (SUV) and tumor to background SUV ratio (T/B ratio) were assessed in primary tumors and cervical lymph nodes.Results: All primary lesions were visualized on FDG-PET images. Even though artifacts from dental materials near the lesion hampered the delineation of primary tumors on CT/MRI, the extent of primary tumors was accurately assessed by FDG-PET. The SUV and T/B ratio in the primary tumor classified in higher T grade (T3 and T4) was significantly higher than that in lower T grade (T1 and T2) (mean ± SD of SUV; 8.32±2.99 vs. 5.15±3.77, p