Abstract
L-3-[(123)]iodo-alpha -methyl-tyrosine (IMT) is a modified amino acid that is avidly taken up by many tumors. Uptake is based on the increased transmembrane transport of amino acids in malignancies. IMT is the only amino acid tracer suitable for SPECT. The aim of this study was to determine the feasibility of IMT SPECT in the detection, staging, and treatment evaluation of non-small cell lung cancer. Methods: We evaluated 44 IMT SPECT studies in 17 patients with histologically proven non-small cell lung cancer, stage ill, IMT SPECT and planar imaging of the chest was performed before, 2 wk after, and 3 mo after 60 Gy radiotherapy. Staging was based on the findings of bronchoscopy, chest CT, mediastinoscopy, or explorative thoracotomy. After radiotherapy, CT and bronchoscopy were repeated to assess tumor response. Results: In 15 of 16 evaluable primary tumors, avid IMT uptake was present (sensitivity, 94%), with a mean (+/- SD) tumor-to-background ratio (T/B) of 2.95 +/- 0.78 (range, 1.7-4.9). In 12 of 14 patients (86%) with mediastinal involvement, IMT SPECT detected one or more mediastinal metastases. However, only 13 of 20 mediastinal metastases were detected in lesion analysis (lesion-based sensitivity, 65%). For lesions <2 cm in diameter, sensitivity was 42%. FDG PET(available for 5 patients) detected more known and unknown lesions than did IMT SPECT. After radiotherapy, T/B had fallen to 1.84 0.29 (P <0.001 vs. baseline), and 3 mo later to 1.61 0.41 (not statistically significant vs. second study). Considerable nonspecific uptake was found in irradiated normal lung tissue (mean ratio to nonirradiated tissue, 1.79 +/- 0.53), persisting for > 3 mo. No relationship was observed between various IMT uptake parameters and the presence of residual viable tumor tissue or survival. Conclusion: IMT SPECT has a high sensitivity for the detection of primary non-small cell lung cancer. Although patient-based sensitivity in detecting mediastinal spread was adequate, sensitivity for individual lesions, especially for small metastases (
| Original language | English |
|---|---|
| Pages (from-to) | 579-585 |
| Number of pages | 7 |
| Journal | Journal of Nuclear Medicine |
| Volume | 42 |
| Issue number | 4 |
| Publication status | Published - Apr-2001 |
Keywords
- I-123-methyl-tyrosine
- lung cancer
- mediastinal staging
- SPECT
- treatment evaluation
- POSITRON-EMISSION-TOMOGRAPHY
- LYMPH-NODE METASTASIS
- TUMOR-TISSUE
- PET
- METHIONINE
- TYROSINE
- CT
- L-<METHYL-C-11>METHIONINE
- TECHNETIUM-99M-MIBI
- DEOXYGLUCOSE