18 F-FET PET Compared with 18 F- FDG PET and CT in Patients with Head and Neck Cancer Present by Intern 羅穎駿 Journal of Nuclear Medicine Vol. 47 No © 2006

INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION

INTRODUCTION Characteristics of tumor lesion: Increased glucose metabolism Increased glucose metabolism Increased DNA synthesis Increased DNA synthesis Increased amino acid transportation Increased amino acid transportation Increased presentation of some receptors and antigens Increased presentation of some receptors and antigens

INTRODUCTION Discrimination between tumor and reactive tissue changes may be difficult based solely on morphologic criteria, for example, by CT and MRI Discrimination between tumor and reactive tissue changes may be difficult based solely on morphologic criteria, for example, by CT and MRI 18 F-FDG has a sensitivity of 80% – 100% for the detection of primary tumors, tumor recurrences, and occult metastases, but is not specific for cancer cells and exhibits high uptake in macrophages, fibroblasts, and granulation tissue 18 F-FDG has a sensitivity of 80% – 100% for the detection of primary tumors, tumor recurrences, and occult metastases, but is not specific for cancer cells and exhibits high uptake in macrophages, fibroblasts, and granulation tissue

INTRODUCTION Artificial amino acid that is not incorporated into proteins but exhibits high uptake in tumor cells because of increased transport via the amino acid transport systems L and B 0,+ Artificial amino acid that is not incorporated into proteins but exhibits high uptake in tumor cells because of increased transport via the amino acid transport systems L and B 0,+ Animal experiments show that 18 F- FET, in contrast to 18 F-FDG, exhibits no uptake in inflammatory cells or in inflammatory lymph nodes Animal experiments show that 18 F- FET, in contrast to 18 F-FDG, exhibits no uptake in inflammatory cells or in inflammatory lymph nodes

INTRODUCTION Squamous cell carcinoma (SCC) is the major histologic type of the head and neck neoplasm Squamous cell carcinoma (SCC) is the major histologic type of the head and neck neoplasm Selective uptake of O-(2- [18F]fluoroethyl)-L-tyrosine (FET) in cerebral gliomas and in SCC Selective uptake of O-(2- [18F]fluoroethyl)-L-tyrosine (FET) in cerebral gliomas and in SCC Good distinction between tumor and inflammation Good distinction between tumor and inflammation

INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION

MATERIALS AND METHODS Twenty-one patients (3 women and 18 men; age range, 41 – 80 y; mean, 61 y) with suspected head and neck tumors underwent 18 F-FET PET, 18 F-FDG PET, and CT within 1 wk before operation Twenty-one patients (3 women and 18 men; age range, 41 – 80 y; mean, 61 y) with suspected head and neck tumors underwent 18 F-FET PET, 18 F-FDG PET, and CT within 1 wk before operation After coregistration, the images were evaluated by 3 independent observers and an ROC analysis was performed, with the histopathologic result used as a reference After coregistration, the images were evaluated by 3 independent observers and an ROC analysis was performed, with the histopathologic result used as a reference

MATERIALS AND METHODS The CT images, the 18 F-FDG PET images, and the 18 F-FET PET images The CT images, the 18 F-FDG PET images, and the 18 F-FET PET images For each patient, the observers evaluated 5 anatomic regions or levels: For each patient, the observers evaluated 5 anatomic regions or levels: level 1, nasopharynx; level 2, oropharynx; level 3, hypopharynx/larynx; region 4, right cervical lymph nodes; region 5, left cervical lymph nodes level 1, nasopharynx; level 2, oropharynx; level 3, hypopharynx/larynx; region 4, right cervical lymph nodes; region 5, left cervical lymph nodes

MATERIALS AND METHODS Each observer recorded suspected lesions and gave each level a confidence rating based on a 6-point scale, a rating score of 4 or greater was considered positive for tumor tissue Each observer recorded suspected lesions and gave each level a confidence rating based on a 6-point scale, a rating score of 4 or greater was considered positive for tumor tissue Furthermore, the maximum standardized uptake values (SUVs) in the lesions were determined Furthermore, the maximum standardized uptake values (SUVs) in the lesions were determined

INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION

RESULTS In 18 of 21 patients, histologic examination revealed SCC, and in 2 of these patients, a second SCC tumor was found at a different anatomic site In 18 of 21 patients, histologic examination revealed SCC, and in 2 of these patients, a second SCC tumor was found at a different anatomic site In 3 of 21 patients, inflammatory tissue and no tumor were identified In 3 of 21 patients, inflammatory tissue and no tumor were identified

RESULTS Eighteen of 20 SCC tumors were positive for both 18 F-FDG uptake and 18 F-FET uptake, one 0.3-cm SCC tumor was detected neither with 18 F- FDG PET nor with 18 F-FET PET, and one 0.7-cm SCC tumor in a 4.3-cm ulcer was overestimated as a 4-cm tumor on 18 F-FDG PET and missed on 18 F-FET PET. Eighteen of 20 SCC tumors were positive for both 18 F-FDG uptake and 18 F-FET uptake, one 0.3-cm SCC tumor was detected neither with 18 F- FDG PET nor with 18 F-FET PET, and one 0.7-cm SCC tumor in a 4.3-cm ulcer was overestimated as a 4-cm tumor on 18 F-FDG PET and missed on 18 F-FET PET.

RESULTS 18 F-FDG PET (A), CT (B), and 18 F-FET PET (C) Images of a 52-y-old man with a 0.7-cm SCC in 4.3-cm ulcer with inflammatory tissue (arrows)

RESULTS Inflammatory tissue was positive for 18 F-FDG uptake (SUV, 3.7 – 4.7) but negative for 18 F-FET uptake (SUV, 1.3 – 1.6) Inflammatory tissue was positive for 18 F-FDG uptake (SUV, 3.7 – 4.7) but negative for 18 F-FET uptake (SUV, 1.3 – 1.6) 18 F-FDG PET (A), CT (B), and 18 F-FET PET (C)

RESULTS The SUVs of 18 F-FDG in SCC were significantly higher (13.0 ± 9.3) than those of 18 F-FET (4.4 ± 2.2) The SUVs of 18 F-FDG in SCC were significantly higher (13.0 ± 9.3) than those of 18 F-FET (4.4 ± 2.2) 18 F-FDG PET (A), CT (B), and 18 F-FET PET (C)

RESULTS In the lymph node metastases (n = 5), with an average size of 1.1 ± 0.6 cm, no increased 18 F-FET uptake could be identified (mean SUV, 1.4 ± 0.3; range, 1.0 – 1.9) In the lymph node metastases (n = 5), with an average size of 1.1 ± 0.6 cm, no increased 18 F-FET uptake could be identified (mean SUV, 1.4 ± 0.3; range, 1.0 – 1.9) The corresponding SUV for 18 F-FDG uptake ranged from 1.6 to 3.3 (mean, 2.3 ± 0.7); 2 of 5 lymph node metastases had an SUV above 2.5 and 3 of 5 had an SUV below 2.5 The corresponding SUV for 18 F-FDG uptake ranged from 1.6 to 3.3 (mean, 2.3 ± 0.7); 2 of 5 lymph node metastases had an SUV above 2.5 and 3 of 5 had an SUV below 2.5

RESULTS The sensitivity of 18 F-FDG PET was 93%, specificity was 79%, and accuracy was 83%. The sensitivity of 18 F-FDG PET was 93%, specificity was 79%, and accuracy was 83%. 18 F-FET PET yielded a lower sensitivity of 75% but a substantially higher specificity of 95% (accuracy, 90%) 18 F-FET PET yielded a lower sensitivity of 75% but a substantially higher specificity of 95% (accuracy, 90%)

RESULTS The ROC analysis showed significantly superior detection of SCC with 18 F-FET PET or 18 F-FDG PET than with CT The ROC analysis showed significantly superior detection of SCC with 18 F-FET PET or 18 F-FDG PET than with CT No significant difference (P = 0.71) was found between 18 F-FDG PET and 18 F-FET PET No significant difference (P = 0.71) was found between 18 F-FDG PET and 18 F-FET PET

INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION

DISCUSSION Detection of SCC was not better with 18 F-FET PET than with 18 F-FDG PET, and no significant difference in accuracy was identified in an ROC analysis Detection of SCC was not better with 18 F-FET PET than with 18 F-FDG PET, and no significant difference in accuracy was identified in an ROC analysis The specificity of 18 F-FET PET for the detection of SCC was superior to that of 18 F-FDG PET and CT The specificity of 18 F-FET PET for the detection of SCC was superior to that of 18 F-FDG PET and CT

DISCUSSION The differences in sensitivity and specificity may be attributed partly to the relatively low 18 F-FET uptake in the tumors The differences in sensitivity and specificity may be attributed partly to the relatively low 18 F-FET uptake in the tumors This low uptake leads to a poorer detection rate, especially in small tumors, which are missed because of partial-volume effects This low uptake leads to a poorer detection rate, especially in small tumors, which are missed because of partial-volume effects

DISCUSSION Because uptake and sensitivity are lower for 18 F-FET than for 18 F-FDG, 18 F-FET does not represent an ideal tracer for the evaluation of primary SCC of the head and neck region Because uptake and sensitivity are lower for 18 F-FET than for 18 F-FDG, 18 F-FET does not represent an ideal tracer for the evaluation of primary SCC of the head and neck region

DISCUSSION The higher specificity makes 18 F-FET PET an interesting additional tool in the follow-up of patients with SCC The higher specificity makes 18 F-FET PET an interesting additional tool in the follow-up of patients with SCC Monitoring of radio- or chemotherapy of SCC, because the reaction of the tumor tissue may be specifically detected without the interfering uptake by inflammatory or reactive tissue Monitoring of radio- or chemotherapy of SCC, because the reaction of the tumor tissue may be specifically detected without the interfering uptake by inflammatory or reactive tissue

INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSION

18 F-FET may not replace 18 F-FDG in the PET diagnostics of head and neck cancer but may be a helpful additional tool in selected patients by allowing better differentiation of tumor tissue from inflammatory tissue 18 F-FET may not replace 18 F-FDG in the PET diagnostics of head and neck cancer but may be a helpful additional tool in selected patients by allowing better differentiation of tumor tissue from inflammatory tissue The sensitivity of 18 F-FET PET in SCC, however, was inferior to that of 18 F- FDG PET because of lower SUVs The sensitivity of 18 F-FET PET in SCC, however, was inferior to that of 18 F- FDG PET because of lower SUVs

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18 F-FET PET Compared with 18 F- FDG PET and CT in Patients with Head and Neck Cancer Presented by Intern 羅穎駿 Journal of Nuclear Medicine Vol. 47 No © 2006