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J T Lewis

Publications and source records attributed to J T Lewis.

27 records · Page 2Linked to original sources
PubMed1976

Lack of specificity for detection of breast lesions with radioactive cesium chloride.

Detection of breast disease at an early stage was evaluated with 131CsCl. The tissue distribution study showed that malignant tumors could be distinguished from both benign and normal tissue by the degree of 131Cs concentration. However, the external counting method was not sensitive enough to warrant general application to patients with a suspected malignant tumor of the breast. False-positive breast study findings using radionuclides, such as 131CsCl, require close follow-up study in view of possible malignant changes in benign disease of the breast.

Adenofibroma↗
PubMed1976

The use of radioactive cesium chloride for imaging of malignant and benign pulmonary lesions.

129CsCl was investigated as an agent for imaging tumors of the lung, and based on the results of 56 patients studied, it has proved to be highly sensitive in detecting primary malignant tumors of the lung. The differentiation between pulmonary malignant lesions and tuberculosis appears to be feasible. However, false-positive images in patients with benign conditions are inevitable.

Adenocarcinoma↗
PubMed1976

Intercomparison of myocardial imaging agents: 201Ti, 129Cs, 43K, and 81Rb.

Thallium-201, 129Cs, 43K, and 81Rb were evaluated as "static" myocardial-imaging agents. Optimal settings of the scintillation camera were determined for each agent. Accumulation for good-quality images can be started as early as 5 min after the dose with 43K, 10 min with 201T1, and 30 min with 129Cs. Imaging times were comparable for 43K, 129Cs, and 201T1 (using the 80-keV x-rays). High-energy photons from the 81Rb preparation, largely from 82mRb contaminant, made it impossible to obtain an interpretable image without the addition of more shielding. Absorbed radiation dose from 81Rb is lower than that from 43K, 129Cs, and 201T1. The highest background activity was observed with 81Rb, followed by 43K, 129Cs, and 201T1 in that order. Overall, 201T1 was best suited for imaging acute myocardial infarction with currently available equipment, and 129Cs was next best. However, because of instrument setting and commercially obtained preparations, 81Rb could not be properly compared with the other radionuclides in our study.

Animals↗
PubMed1975

Interpretation of radionuclide liver images: do training and experience make a difference?

Individual observers interpreted images in order to assess their accuracy and sources of error. Seventy-six liver images were presented to nine readers for interpretation. Readers of differing experience participated in the study: four radiology residents, three fellows in nuclear medicine, and two full-time nuclear medicine physicians. A higher incidence of false-positive reading was more common in inexperienced observers (11-50%) and the most correct readings were obtained by staff physicians (88% overall percentage accuracy). Heterogeneity in radionuclide uptake was the most frequently ill-defined nature was the most common false-positive finding in normal cases. Early stages of cirrhosis, mild hepatitis, and rare diseases such as hepatic sarcoidosis were difficult to detect. Skill of interpretation improved with experience, especially in judging heterogeneity of an ill-defined nature, and the rate of accurate readings was proportional to the level of training of the observer.

Cysts↗
PubMedDate not supplied

A study of the physiologic relationship of lower and upper airways with 133Xe.

In order to test the hypothesis that there is air streaming through the upper airways to the ipsilateral lung, and that reflex hypoventilation of the ipsilateral lung may occur in unilateral nasal obstruction, 11 volunteers and three patients were examined for these phenomena, employing Xenon-133 (133Xe) and a special mask permitting inhalation of the gas through one nostril at a time. Patients with deviated nasal septa were also examined, one of these before and after surgery. There was no difference in 133Xe distribution between right and left lungs when gas was inhaled through either normal nostril as compared to inhalation through the mouth, in patients with deviated septa or with cotton obstruction of the contralateral nostril. Furthermore, there was no evidence of delayed washout of 133Xe from either lung or any segment thereof under conditions of nasal obstruction. Thus acute or chronic nasal obstruction does not alter the distribution of inpired gas to the lungs. Neither air streaming nor reflex bronchoconstriction occurs with nasal obstruction.

Airway Obstruction↗