PRELIMINARY EXPERIENCE WITH THALLOUS CHLORIDE T1 201-LABELED SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY SCANNING IN HEAD AND NECK-CANCER

Objectives: To test the feasibility of single-photon emission computed tomography (SPECT) scanning with the use of thallous chloride Tl 201 in patients with head and neck cancer and to decide its possible appli cations to improve the diagnosis and staging of head and neck cancer. Design: Findings from SPECT with the use of 4.32 mCi of thallous chlor ide Tl 201 were compared with those from clinical examination, compute d tomography (CT), magnetic resonance imaging, ultrasound-guided fine- needle aspiration, and histologic studies. Primary sites and neck node s were separately studied. Accuracy, sensitivity, and specificity were calculated for 19 patients who were being assessed for initial treatm ent (primary sites) and for 12 neck node dissections in 10 patients. S etting: The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospi tal, Amsterdam. Patients: A consecutive sample of 25 patients with hea d and neck cancers of different sites. The average age of the patients was 60.2 years, and there were 19 men and six women. The sites of the primary lesions were as follows: oropharynx (n=5), larynx (n=9), oral cavity (n=4), nasopharynx (n=1), hypopharynx (n=3), and unknown (n=3) . Results: For the primary lesions, SPECT identified 94% of the lesion s; SPECT was more accurate in delineating four oropharyngeal lesions a nd one nasopharyngeal lesion. In 12 neck node dissections, SPECT ident ified all of the positive lesions and two negative lesions, whereas CT detected two false-positive lesions. Single-photon emission computed tomography gave less information about the number of nodes and the ana tomy than did CT or magnetic resonance imaging. Conclusions: Single-ph oton emission computed tomography with the use of thallous chloride Tl 201 appears to be useful in helping to identify occult primary lesion s, particularly in the oropharynx. It may assist CT or magnetic resona nce imaging in identifying a recurrence of cancer in tissues or in lym ph nodes, and in screening for distant metastases. Although no nodes w ere identified that were not already seen with the use of CT or magnet ic resonance imaging, SPECT may help to eliminate the false-positive l esions, and SPECT with the use of thallous chloride Tl 201 appears to be a valuable new tool in helping to diagnose and stage head and neck cancer.