Thallium-201-Chloride Lung Imaging for Bronchogenic Carcinoma

Abstract

To evaluate the clinical utility of thallium-201-(²⁰¹Tl) chloride lung imaging for patients with suspected lung tumor or recurrent tumor before and/or after thoracic surgery, 33 men (aged 50 to 79; mean 62) with recurrent or suspected carcinoma of the lung underwent²⁰¹ Tl-chloride planar lung imaging. Planar lung images (anterior, posterior, and lateral views) were obtained 15 min after i.v. injection of 2–4 mCi of²⁰¹ Tl-chloride. Thallium-201 lung images were compared with concurrent computed tomography of the chest and correlated to the pathologic results from bronchial washing, bronchoscopic biopsy, lobectomy and/or pneumonectomy. In 23 of 33 patients, planar images were compatible with carcinoma manifesting focal areas of uptake. Ten of the 33 patients had diffuse lung uptake or focal area of lung uptake, while six patients had diffuse or focal uptake of the lung in a nonmalignant condition which interfered with interpretation. Six benign lesions included one in chronic inflammation, one in pneumonia, one in granulomatous inflammation, one in squamous metaplasia, and two in nonmalignancy. Three of the six patients’ lung images showed focal areas of uptake and lung images of three others demonstrated diffuse lung uptake. Diffuse lung uptake in malignant lesions(s) of four patients interfered with scan interpretation. Four of these six patients with nonmalignant conditions and two of four patients with diffuse uptake in malignant lesion(s) had a history of smoking and/or obstructive lung disease, two had undergone recent thoracotomy and one postirradiation. These results suggest²⁰¹ Tl-chloride localized in the benign lesions of the lung and/or diffuse lung uptake may interfere with the interpretation of²⁰¹ Tl-chloride lung images.