99mTc-depreotide生长抑素受体显像的临床应用研究

生长抑素受体显像近年来研究较多，depreotide已成为其研究热点之一。Depreotide在诊断与鉴别诊断临床常见的孤立性肺结节方面有其独特优势；此外，^99mTc—depreotide生长抑素受体显像在乳腺癌、甲状腺癌、淋巴瘤等肿瘤及甲状腺相关性眼病等非肿瘤性疾病也有一定应用前景。     

A method for assessing quality of control from glucose profiles.

AIM: As the practice of multiple assessments of glucose concentration throughout the day increases for people with diabetes, there is a need for an assessment of glycaemic control weighted for the clinical risks of both hypoglycaemia and hyperglycaemia. METHODS: We have developed a methodology to report the degree of risk which a glycaemic profile represents. Fifty diabetes professionals assigned risk values to a range of 40 blood glucose concentrations. Their responses were summarised and a generic function of glycaemic risk was derived. This function was applied to patient glucose profiles to generate an integrated risk score termed the Glycaemic Risk Assessment Diabetes Equation (GRADE). The GRADE score was then reported by use of the mean value and the relative percent contribution to the weighted risk score from the hypoglycaemic, euglycaemic, hyperglycaemic range, respectively, e.g. GRADE (hypoglycaemia%, euglycaemia%, hyperglycaemia%). RESULTS: The GRADE scores of indicative glucose profiles were as follows: continuous glucose monitoring profile non-diabetic subjects GRADE = 1.1, Type 1 diabetes continuous glucose monitoring GRADE = 8.09 (20%, 8%, 72%), Type 2 diabetes home blood glucose monitoring GRADE = 9.97 (2%, 7%, 91%). CONCLUSIONS: The GRADE score of a glucose profile summarises the degree of risk associated with a glucose profile. Values < 5 correspond to euglycaemia. The GRADE score is simple to generate from any blood glucose profile and can be used as an adjunct to HbA1c to report the degree of risk associated with glycaemic variability.     

Quantitative Analysis of the Tomographic Technetium－99m MIBI （~（99m）Tc－MIBI） Myocardial Bullseye Display： Application to Diag

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Localization of parathyroid enlargement: experience with technetium-99m methoxyisobutylisonitrile and thallium-201 scintigraphy,ultrasonography and computed tomography

Technetium-99m methoxyisobutylisonitrile (MIBI), like thallium-201, has recently been introduced as a myocardial perfusion agent and is now also showing very promising results in parathyroid scintigrapy. The results of ²⁰¹Tl/^99mTc-pertechnetate and ^99mTc-MIBI/^99mTc-pertechnetate subtraction scintigraphy, ultrasonography and computed tomography are presented in a series of 43 patients operated on for hyperparathyroidism. All four imaging modalities were confirmed to be reliable, scintigraphy being the most accurate. Sensitivities ranged from 81% to 95%, that of ^99mTc-MIBI being the highest. Moreover this tracer, which has more favourable physical and also biochemical properties, yielded images of superior quality. This allowed localization of the lesion by visual inspection only in as many as 86% of the patients with positive ^99mTc-MIBI/^99mTc-pertechnetate subtraction scintigraphy. We believe that the higher sensitivity, superior image quality and lower cost of ^99mTc-MIBI imaging will make ^99mTc-MIBI the new radiopharmaceutical of choice for parathyroid scintigraphy (when one takes into account the stability of labelling with large activities it is possible to perform three or four cardiac studies together with one parathyroid scintigraphic examination using one lyophililzed vial).     

Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake

Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT_2A receptorbinding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pK _a value leads to ionization of the molecule at blood pH, the pK _a value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pK _a value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pK _a cannot be simply explained by the increase in the pK _a-governed proportion of the neutral species.     

Different kinetics of lung clearance of technetium-99m labelled diethylene triamine penta-acetic acid in patients with sarcoidosis and smokers

The rate of clearance from the lungs of inhaled technetium-99m labelled diethylene triamine penta-acetic acid (^99mTc-DTPA) is often increased in interstitial lung disease as well as in smoking. In smokers a bi-exponential clearance course of ⁹⁹mTc-DTPA when measured over 3 h has previously been shown. This study was performed to compare the kinetics of clearance of ^99mTc-DTPA, measured for 3 h, in sarcoid patients and healthy smokers. Forty-one never-smoking patients with sarcoidosis and radiological signs of intrathoracic disease were studied. The results were compared with those of 16 healthy current smokers and of 14 healthy never-smokers reported previously. A mono-exponential clearance equation described the clearance in 22 of the sarcoid patients and all normal never-smokers, but with a shorter average tracer half-life in the patients (P<0.05). In 19 patients and all smokers a bi-exponential equation gave a significantly better curve fit. The rate of clearance of the slow component was higher in patients with sarcoidosis than in smokers (P< 0.05). The fraction of the tracer cleared by the fast clearance component was smaller in patients with sarcoidosis than in smokers (P<0.01). Differences in kinetics of clearance of ^99mTc-DTPA in sarcoidosis and smoking could thus be demonstrated, suggesting that the abnormal clearance is caused by diverging pathophysiological mechanisms.     

Nitrate administration to enhance the detection of myocardial viability by technetium-99m tetrofosmin single-photon emission tomography

A comparison was performed between technetium-99m tetrofosmin myocardial perfusion tomography at baseline and after nitrate administration, using a 2-day protocol, and rest-reinjection thallium-201 single-photon emission tomography (SPET) studies in order to assess whether nitrates enhance the detection of viable myocardium with^99mTc-tetrofosmin. Fifteen patients with coronary artery disease, previous myocardial infarction and a left ventricular ejection fraction <40% underwent²⁰¹T1 rest-injection and^99mTc-tetrofosmin. baseline-postnitroglycerin (0.4 mg sublingually) SPET studies, within 48 h. Tomograms based on the three spatial planes were divided into 15 segments and regional tracer uptake was quantitatively analysed. Viability was defined as presence of tracer uptake >50% of peak activity on baseline studies or after reversibility. The percentage of peak activity of^99mTc-tetrofosmin at baseline correlated with that of 201T1 (r=0.82,P <0.001). On baseline^99mTc-tetrofosmin studies, 73 of the 225 segments that were analysed had <50% of peal. activity. Fifteen percent of these segments showed reversibility after nitrate administration, with an increase in^99mTc-tetrofosmin uptake from 40%±9% to 57%±9% of peak activity (P=0.003). All reversible segments after nitrate administration had viability criteria on²⁰¹Tl studies, but 20 segments that were non-viable on^99mTc-tetrofosmin. studies were viable on²⁰¹Tl studies. Using a threshold value of >40% of peak activity, only seven segments remained non-viable on^99mTc-tetrofosmin studies. Overall agreement between^99mTc-tetrofosmin with nitrates and²⁰¹Tl-reinjection regarding the presence of myocardial viability was 90%. Detection of myocardial viability with^99mTc-tetrofosmin. was enhanced after nitrate administration, correlating with viability criteria observed on thallium studies.     

Radionuclide venography vs Tc-99m-RBC equilibrium angiography: A comparative paired study

Combined direct injection venography (DIV) and equilibrium angiography (EA) were performed in 13 patients, by injecting in vitro labeled ^99mTc autologous RBC, via pedal veins, and imaging the first pass and the equilibrium phase. This paired comparative study of DIV with EA shows that DIV has advantages over EA because it provides selective information on the deep venous system from the calves to the inferior vena cava. DIV provides information on the flow dynamics and the high contrast first pass images provide better definition of non filling venous segments as well as visualization of collaterals. When using ^99mTc-MAA, lung perfusion can also be imaged. DIV is recommended as the procedure of choice for the diagnosis of DVT and EA should be employed only when pedal vein injection is not possible.     

Rest-injected thallium-201 redistribution and resting technetium-99m methoxyisobutylisonitrile uptake in coronary artery disease: relation to the severity of coronary artery stenosis

To compare rest-injected thallium-201 (Tl) redistribution and resting technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI) myocardial uptake in chronic coronary artery disease (CAD), 15 patients with angiographically proven CAD and left ventricular (LV) dysfunction (ejection fraction 34%±9%) were studied. All patients underwent rest-redistribution Tl and resting ^99mTc-MIBI cardiac imaging. Gated ^99mTc-MIBI images were also acquired to assess regional LV wall motion (WM). Myocardial segments (n=225) were divided into three groups on the basis of the degree of coronary artery stenosis: group 1 (total occlusion, n=82), group 2 (50%–99% of stenosis, n=84) and group 3 (<50% of stenosis, n=59). WM was significantly worse in groups 1 and 2 compared to group 3 (P<0.001), but no difference was observed between groups 1 and 2. TI and ^99mTc-MIBI uptake were significantly lower in groups 1 and 2 compared to group 3 (P < 0.001), and in group 1 compared to group 2 (P<0.001). When TI and ^99mTc-MIBI uptake were directly compared, TI uptake was higher than ^99mTc-MIBI uptake in group 1 (P<0.001), while no significant difference was observed in groups 2 and 3. Thus, both rest-injected TI redistribution and resting ^99mTc-MIBI uptake reflected the severity of coronary artery stenosis in CAD. However, in myocardial segments with total coronary occlusion T1 uptake was significantly higher than ^99mTc-MIBI uptake. Our data suggest that rest-injected Tl redistribution cardiac imaging may identify, more accurately than resting ^99mTc-MIBI imaging, the presence of viable myocardium in chronic CAD, particularly when the coronary blood flow is severely impaired.     

Antiserotonergic inhibition of calcitonin-induced increase of β-endorphin,ACTH, and cortisol secretion

Summary In a previous study we observed that calcitonin increases -endorphin, ACTH, and cortisol secretion. We assumed that calcitonin might have a modulatory role on the pituitary function. The present study was initiated to clarify whether this effect is due to a direct pituitary stimulation or to an indirect stimulation through CRF (corticotropin releasing factor).Fourteen healthy subjects, aged 30–60 years were investigated. All the subjects received 100IU Salmon calcitonin Sandoz i.v. at 8a.m. (time 0). Plasma -endorphin, ACTH and cortisol were estimated every 30min from – 30 to 120 min by specific radioimmunoassay. The same parameters were estimated a second time, at the same intervals, when cyproheptadine 8 mg (7 subjects) and 40 mg propranolol (7 subjects) were given per os at – 30 min and calcitonin i.v. at time 0. -endorphin, ACTH and cortisol levels (Mean ±SEM) rose significantly after calcitonin (peak value at 30–90 min) from 5.2 ±0.7 to 15.1±2.6 pmol/l; from 43.0±2.7 to 70.7±4.1 pg/ml and from 10.6±1.5 to 19.6 ±2.1 g/100 ml respectively (p< 0.0001 by analysis of variance and covariance and repeated measures). Propranolol 40 mg (per os) administered at time – 30 did not alter the response of -endorphin, ACTH and cortisol to calcitonin (infused at time 0).Cyproheptadine, the antiserotonergic substance that inhibits the synthesis and release of CRF completely inhibited the stimulatory effect of calcitonin.We conclude that probably calcitonin has a modulatory role on the hypothalamo-pituitary adrenal axis and that it acts at the hypothalamic level probably by stimulating CRF secretion.