J. B. van der Schoot

Thallium-201 scanning to decide CCU admission in patients with non-diagnostic electrocardiograms.

To determine the value of thallium-201 scintigraphy as a decisive factor in admission policy for patients with acute chest pain and nondiagnostic electrocardiograms, we undertook a prospective study in 149 such patients. The interval between pain and scan never exceeded 12 hr. Of 57 patients in whom a defect was seen, 34 had an acute infarction, 7 developed infarction within 2 months, and in 11 coronary heart disease was proven by angiography or strongly suggested by stress tests (ECG and thallium-201 scan). In 13 patients with an equivocal scan, coronary heart disease was proven or strongly suggested in 5. Of 79 patients with a normal scan, only 1 had acute infarction, and stress tests were positive in 6 and negative in 72. In these 72 no cardiac event occurred during a 1-year follow-up. Thallium-201 scintigraphy can help to select those patients with acute chest pain and nondiagnostic electrocardiograms who need observation in a CCU.

European multi-centre comparison of thallium 201 and technetium 99m methoxyisobutylisonitrile in ischaemic heart disease

Fifty-six patients in Europe were entered into a multi-centre study to compare the accuracy of technetium 99m methoxyisobutylisonitrile (99mTc-MIBI) for the detection of coronary artery disease (CAD) with thallium 201 (201T1) chloride perfusion scanning. The results showed a high degree of concordance between the two radiopharmaceuticals. Some 81% (678/840) of myocardial segments showed the same result (normal, infarct or ischaemia), and 80% (45/56) of patients had the same diagnosis. Overall detection of CAD in patients was 98% for201T1 and 96% for99mTc-MIBI. Detection of CAD in total arteries was 68% for both agents. In this study99mTc-MIBI was as accurate as201T1 for the detection of coronary artery stenoses.

67Ga scintigraphy as an index of disease activity in pulmonary sarcoidosis

Gallium-67 scintigraphy was performed in 38 patients with pulmonary sarcoidosis to assess its value as a supplement to the clinical, radiographical and functional investigations. In 32 (84%) of the 38 patients the scan was abnormal and showed 67Ga uptake in the pulmonary parenchyma and/or hilum. The incidence and severity of pulmonary symptoms correlated poorly with the localization and degree of 67Ga accumulation. During the clinical follow-up of untreated patients 67Ga scintigraphy showed regression earlier than chest radiography. Large doses of corticosteroids decreased the accumulation of 67Ga in the pulmonary parenchyma and hilum. The chest radiographical improvement was more gradual.The 67Ga scan can be used as an index of disease activity in the follow-up of patients with pulmonary sarcoidosis, whether or not they are treated with corticosteroids. Nevertheless, the results have to be considered together with other clinical data.

Evaluation of routine pre-operative bone scintigraphy in patients with breast cancer

Abstract A prospective study on bone scanning was undertaken in patients with a clinical operable breast carcinoma to investigate its use in the staging of these patients. From 90 patients with a proven breast carcinoma, stages T 1 , T 2 , N 0 , N 1a , the pre-operative whole body skeletal scintigraphy was positive in 7 cases. Four of these could be excluded because other reasons than metastases could be demonstrated to be the cause of the positive scan. So in only 3 cases ( 3·4% ) the scan was positive, suggesting bone metastases. These lesions could, up to now in no way be proven to be metastases. The final percentage of pre-operative detection of bone metastasis after a longer follow up period may therefore even be less than 3·4% . We therefore decided to omit routine pre-operative bone scanning in patients with a breast carcinoma stages T 1 , T 2 , N 0 , N 1a .

A method of quantitative 67Ga scintigraphy in the evaluation of pulmonary sarcoidosis

Abstract67Ga scintigraphy was performed in 42 patients with pulmonary sarcoidosis and in 30 control subjects. Accumulation of the radionuclide in hili and lungs was quantified by a computer method. The values in control subjects were found to be within a relatively narrow range. The pattern of 67Ga accumulation clearly differed in patients who were radiographically defined as having only lymphadenopathy and in patients also having parenchymal involvement. Corticosteroid therapy resulted in a sharp decline of values of isotope uptake, although hilar activity remained slightly elevated. The quantitative uptake measurement proved to be superior to a subjective scoring method.

Bone scintigraphy in patients with operable breast cancer stages I and II. Final conclusion after five-year follow-up

A 5-yr follow-up study was performed in 90 patients with stage I and II breast cancer who had a routine preoperative bone scan. The percentage of positive preoperative scans was 3.4%. Twenty-four of the 90 patients died within 5 yr. In all patients except five a follow-up scan was obtained. The results of our first study were confirmed. In only one of the three patients with a positive preoperative scan suspicious for bone metastases did bone metastases develop in this 5-yr follow-up study. One patient with an equivocal preoperative scan developed bone metastases. In 14 of the 16 patients with bone metastases and a positive scan in the follow-up period the preoperative scan was negative. From the preoperative and follow-up scan results we conclude that in stage I and II breast cancer there is no value in preoperative bone scanning. Routine bone scanning in the follow-up period appears to have little value in the asymptomatic patient.

111In-Labelled Platelets in the Diagnosis of Kidney Transplant Rejection

Deterioration of kidney graft function shortly after surgery occurs frequently due to various disorders. Often it may be difficult to differentiate the diagnosis of graft rejection from other complications like acute tubular necrosis, vascular or urological problems or viral infections. A similar problem exists in determining the different types of rejection, i.e. vascular or cellular.

201Tl-diethyldithiocarbamate: a possible radiopharmaceutical for brain imaging

For estimating regional brain perfusion with a gamma camera lipophilic radiopharmaceuticals are required. This paper describes the development of201Tl-diethyldithiocarbamate (201TlDDC). First the compound NaDDC was tested for stability and an assay was developed. Next the201TlDDC complex was prepared and checked for lipophilicity and stability by paper chromatography. A scintigraphic pilot study using this agent in a rabbit showed considerable brain uptake, compared to201TlCl. Finally we performed a study in rats on the distribution of201TlDDC in different organs. The results confirmed the lipophilicity of the agent. Within the first hour the percentage of injected dose per gram tissue was 2.73% in the cerebrum and 1.35% in the cerebellum. These data are in good agreement with some other agents used for assessment of brain blood flow.

Bone scintigraphy and densitometry in symptomatic haemodialysis bone disease

Bone scintigraphy and densitometry (iodine-125 photon absorptiometry) were performed in eight patients with symptomatic haemodialysis bone disease. The bone scintiscan showed either hot spots or hyperactivity as a feature of metabolic bone disease. The bone density (BMC/W) was reduced, but could not be distinguished from the degree of demineralisation found in asymptomatic patients on longterm haemodialysis. Therefore, bone density measurements require critical interpretation. Complementary bone scintigraphy should be used in symptomatic haemodialysis bone disease for assessing the extent of the disease.

Semi in vitro labelling of red blood cells with99mTc: a comparison with the in vivo labelling

A method ofsemi in vitro labelling of red blood cells (Rbc) is described.Rbc, ‘pre-tinned’ in the body, were labelledin vitro with99mTc. The labelling efficiency, expressed as the percentage of the administered activity found in the blood, appeared to be higher with this preparation method compared toin vivo labelling ofRbc, respectively 91.3±3.6 and 71.3±3.5 (mean±Sem). There was no difference between both methods in elimination of the label in the urine up to one hour (4.6% of the administered activity).The data here presented, show that thesemi in vitro method provides a preparation with a high cell-bound activity of 96%. Because of a better labelling efficiency, application of thesemi in vitro method results in more circulating activity and a higher left ventricle to background ratio.