32nd International Austrian Winter Symposium : Zell am See, the Netherlands. 20-23 January 2016

A1 68Ga-PSMA PET/CT in staging and restaging of Prostate Cancer Patients: comparative study with 18F-Choline PET/CT

W Langsteger, A Rezaee, W Loidl, HS Geinitz, F Fitz, M Steinmair, G Broinger, L Pallwien-Prettner, M Beheshti

A2 F18 Choline PET – CT: an accurate diagnostic tool for the detection of parathyroid adenoma?

L Imamovic, M Beheshti, G Rendl, D Hackl, O Tsybrovsky, M Steinmair, K Emmanuel, F Moinfar, C Pirich, W Langsteger

A3 [18F]Fluoro-DOPA-PET/CT in the primary diagnosis of medullary thyroid carcinoma

A Bytyqi, G Karanikas, M Mayerhöfer, O Koperek, B Niederle, M Hartenbach

A4 Variations of clinical PET/MR operations: An international survey on the clinical utilization of PET/MRI

T Beyer, K Herrmann, J Czernin

A5 Standard Dixon-based attenuation correction in combined PET/MRI: Reproducibility and the possibility of Lean body mass estimation

I Rausch, P Rust, MD DiFranco, M Lassen, A Stadlbauer, ME Mayerhöfer, M Hartenbach, M Hacker, T Beyer

A6 High resolution digital FDG PET/MRI imaging for assessment of ACL graft viability

K Binzel, R Magnussen, W Wei, MU Knopp, DC Flanigan, C Kaeding, MV Knopp

A7 Using pre-existing hematotoxicity as predictor for severe side effects and number of treatment cycles of Xofigo therapy

A Leisser, M Nejabat, M Hartenbach, G Kramer, M Krainer, M Hacker, A Haug

A8 QDOSE – comprehensive software solution for internal dose assessment

Wencke Lehnert, Karl Schmidt, Sharok Kimiaei, Marcus Bronzel, Andreas Kluge

A9 Clinical impact of Time-of-Flight on next-generation digital PET imaging of Yttrium-90 radioactivity following liver radioembolization

CL Wright, K Binzel, J Zhang, Evan Wuthrick, Piotr Maniawski, MV Knopp

A10 Snakes in patients! Lessons learned from programming active contours for automated organ segmentation

M Blaickner, E Rados, A Huber, M Dulovits, H Kulkarni, S Wiessalla, C Schuchardt, RP Baum, B Knäusl, D Georg

A11 Influence of a genetic polymorphism on brain uptake of the dual ABCB1/ABCG2 substrate [11C]tariquidar

M Bauer, B Wulkersdorfer, W Wadsak, C Philippe, H Haslacher, M Zeitlinger, O Langer

A12 Outcome prediction of temporal lobe epilepsy surgery from P-glycoprotein activity. Pooled analysis of (R)-[11C]-verapamil PET data from two European centres

M Bauer, M Feldmann, R Karch, W Wadsak, M Zeitlinger, MJ Koepp, M-C Asselin, E Pataraia, O Langer

A13 In-vitro and in-vivo characterization of [18F]FE@SNAP and derivatives for the visualization of the melanin concentrating hormone receptor 1

M Zeilinger, C Philippe, M Dumanic, F Pichler, J Pilz, M Hacker, W Wadsak, M Mitterhauser

A14 Reducing time in quality control leads to higher specific radioactivity of short-lived radiotracers

L Nics, B Steiner, M Hacker, M Mitterhauser, W Wadsak

A15 In vitro 11C-erlotinib binding experiments in cancer cell lines with epidermal growth factor receptor mutations

A Traxl, Thomas Wanek, Kushtrim Kryeziu, Severin Mairinger, Johann Stanek, Walter Berger, Claudia Kuntner, Oliver Langer

A16 7-[11C]methyl-6-bromopurine, a PET tracer to measure brain Mrp1 function: radiosynthesis and first PET evaluation in mice

S Mairinger, T Wanek, A Traxl, M Krohn, J Stanek, T Filip, M Sauberer, C Kuntner, J Pahnke, O Langer

A17 18F labeled azidoglucose derivatives as “click” agents for pretargeted PET imaging

D Svatunek, C Denk, M Wilkovitsch, T Wanek, T Filip, C Kuntner-Hannes, J Fröhlich, H Mikula

A18 Bioorthogonal tools for PET imaging: development of radiolabeled 1,2,4,5-Tetrazines

C Denk, D Svatunek, T Wanek, S Mairinger, J Stanek, T Filip, J Fröhlich, H Mikula, C Kuntner-Hannes

A19 Preclinical evaluation of [18F]FE@SUPPY- a new PET-tracer for oncology

T Balber, J Singer, J Fazekas, C Rami-Mark, N Berroterán-Infante, E Jensen-Jarolim, W Wadsak, M Hacker, H Viernstein, M Mitterhauser

A20 Investigation of Small [18F]-Fluoroalkylazides for Rapid Radiolabeling and In Vivo Click Chemistry

C Denk, D Svatunek, B Sohr, H Mikula, J Fröhlich, T Wanek, C Kuntner-Hannes, T Filip

A21 Microfluidic 68Ga-radiolabeling of PSMA-HBED-CC using a flow-through reactor

S Pfaff, C Philippe, M Mitterhauser, M Hartenbach, M Hacker, W Wadsak

A22 Influence of 24-nor-ursodeoxycholic acid on hepatic disposition of [18F]ciprofloxacin measured with positron emission tomography

T Wanek, E Halilbasic, M Visentin, S Mairinger, B Stieger, C Kuntner, M Trauner, O Langer

A23 Automated 18F-flumazenil production using chemically resistant disposable cassettes

P Lam, M Aistleitner, R Eichinger, C Artner

A24 Similarities and differences in the synthesis and quality control of 177Lu-DOTA-TATE, 177Lu -HA-DOTA-TATE and 177Lu-DOTA-PSMA (PSMA-617)

H Eidherr, C Vraka, A Haug, M Mitterhauser, L Nics, M Hartenbach, M Hacker, W Wadsak

A25 68Ga- and 177Lu-labelling of PSMA-617

H Kvaternik, R Müller, D Hausberger, C Zink, RM Aigner

A26 Radiolabelling of liposomes with 67Ga and biodistribution studies after administration by an aerosol inhalation system

U Cossío, M Asensio, A Montes, S Akhtar, Y te Welscher, R van Nostrum, V Gómez-Vallejo, J Llop

A27 Fully automated quantification of DaTscan SPECT: Integration of age and gender differences

F VandeVyver, T Barclay, N Lippens, M Troch

A28 Lesion-to-background ratio in co-registered 18F-FET PET/MR imaging – is it a valuable tool to differentiate between low grade and high grade brain tumor?

L Hehenwarter, B Egger, J Holzmannhofer, M Rodrigues-Radischat, C Pirich

A29 [11C]-methionine PET in gliomas - a retrospective data analysis of 166 patients

N Pötsch, I Rausch, D Wilhelm, M Weber, J Furtner, G Karanikas, A Wöhrer, M Mitterhauser, M Hacker, T Traub-Weidinger

A30 18F-Fluorocholine versus 18F-Fluorodeoxyglucose for PET/CT imaging in patients with relapsed or progressive multiple myeloma: a pilot study

T Cassou-Mounat, S Balogova, V Nataf, M Calzada, V Huchet, K Kerrou, J-Y Devaux, M Mohty, L Garderet, J-N Talbot

A31 Prognostic benefit of additional SPECT/CT in sentinel lymph node mapping of breast cancer patients

S Stanzel, G Pregartner, T Schwarz, V Bjelic-Radisic, B Liegl-Atzwanger, R Aigner

A32 Evaluation of diagnostic value of TOF-18F-FDG PET/CT in patients with suspected pancreatic cancer

S Stanzel, F Quehenberger, RM Aigner

A33 New quantification method for diagnosis of primary hyperpatahyroidism lesions and differential diagnosis vs thyropid nodular disease in dynamic scintigraphy

A Koljević Marković, Milica Janković, V Miler Jerković, M Paskaš, G Pupić, R Džodić, D Popović

A34 A rare case of diffuse pancreatic involvement in patient with merkel cell carcinoma detected by 18F-FDG

MC Fornito, D Familiari

A35 TSH-stimulated 18F-FDG PET/CT in the diagnosis of recurrent/metastatic radioiodine-negative differentiated thyroid carcinomas in patients with various thyroglobuline levels

P Koranda, H Polzerová, I Metelková, L Henzlová, R Formánek, E Buriánková, M Kamínek

A36 Breast Dose from lactation following I131 treatment

WH Thomson, C Lewis

A37 A new concept for performing SeHCAT studies with the gamma camera

WH Thomson, J O’Brien, G James, A Notghi

A38 Whole body F-18-FDG-PET and tuberculosis: sensitivity compared to x-ray-CT

H Huber, I Stelzmüller, R Wunn, M Mandl, F Fellner, B Lamprecht, M Gabriel

A39 Emerging role 18F-FDG PET-CT in the diagnosis and follow-up of the infection in heartware ventricular assist system (HVAD)

MC Fornito, G Leonardi

A40 Validation of Poisson resampling software

WH Thomson, J O’Brien, G James

A41 Protection of PET nuclear medicine personnel: problems in satisfying dose limit requirements

J Hudzietzová, J Sabol, M Fülöp

[Protection of the unborn child in diagnostic and interventional radiological procedures]

The radiation exposure of an unborn child should be principally avoided, whenever it is medically reasonably possible; therefore, the identification of pregnant patients is the first and the most important step in radiation protection of the unborn child. However, in cases of emergency saving the life of the patient has a higher priority than the radiation protection of the unborn child. In this review article, we present a longitudinal section through the national and international literature and guidelines as a basis for radiological management of a (possibly) pregnant patient. We also list some radiological procedures recommended in the literature for a series of maternal indications considering the contraindications of each method during pregnancy and radiation protection of the unborn child.

Global decrease of serotonin-1A receptor binding after electroconvulsive therapy in major depression measured by PET

Electroconvulsive therapy (ECT) is a potent therapy in severe treatment-refractory depression. Although commonly applied in psychiatric clinical routine since decades, the exact neurobiological mechanism regarding its efficacy remains unclear. Results from preclinical and clinical studies emphasize a crucial involvement of the serotonin-1A receptor (5-HT(1A)) in the mode of action of antidepressant treatment. This includes associations between treatment response and changes in 5-HT(1A) function and density by antidepressants. Further, alterations of the 5-HT(1A) receptor are consistently reported in depression. To elucidate the effect of ECT on 5-HT(1A) receptor binding, 12 subjects with severe treatment-resistant major depression underwent three positron emission tomography (PET) measurements using the highly selective radioligand [carbonyl-(11)C]WAY100635, twice before (test-retest variability) and once after 10.08±2.35 ECT sessions. Ten patients (~83%) were responders to ECT. The voxel-wise comparison of the 5-HT(1A) receptor binding (BP(ND)) before and after ECT revealed a widespread reduction in cortical and subcortical regions (P<0.05 corrected), except for the occipital cortex and the cerebellum. Strongest reductions were found in regions consistently reported to be altered in major depression and involved in emotion regulation, such as the subgenual part of the anterior cingulate cortex (-27.5%), the orbitofrontal cortex (-30.1%), the amygdala (-31.8%), the hippocampus (-30.6%) and the insula (-28.9%). No significant change was found in the raphe nuclei. There was no significant difference in receptor binding in any region comparing the first two PET scans conducted before ECT. This PET study proposes a global involvement of the postsynaptic 5-HT(1A) receptor binding in the effect of ECT.

Assessment of left ventricular volumes, ejection fraction and mass

Aim: We compared and delineated possible differences of model-based analysis of ECGgated SPECT using 99mTc-sestamibi (Tc- SPECT) with ECG-gated 18F-fluorodeoxyglucose- PET (FDG-PET) for determination of enddiastolic (EDV) and end-systolic (ESV) cardiac volumes, left ventricular ejection fraction (LVEF), and myocardial mass (LVMM). Patients, methods: 24 patients (21 men; age: 54 ± 12years) with coronary artery disease underwent Tc-SPECT and FDG-PET imaging for evaluation of myocardial perfusion and viability. By using model-based analysis EDV, ESV, LVEF and LVMM were calculated from short axis images of both Tc-SPECT and FDGPET. Results: Left ventricular volumes by Tc- SPECT and FDG-PET were 176 ± 60 ml and 181 ± 59 ml for EDV, and 97 ± 44 ml and 103 ± 45 ml for ESV respectively, LVEF was 47 ± 8% by Tc-SPECT and 45 ± 9% by FDG-PET. The LVMM was 214 ± 40 g (Tc-SPECT) and 202 ± 43 g (FDG-PET) (all p = NS, paired t-test). A significant correlation was observed between Tc-SPECT and FDG-PET imaging for calculation of EDV (r = 0.93), ESV (r = 0.93), LVEF (r = 0.83) and LVMM (r = 0.72). Conclusion: ECG-gated Tc-SPECT and FDG-PET using two tracers with different characteristics (perfusion versus metabolism) showed close agreement concerning measurements of left ventricular volumes, contractile function and myocardial mass by using a model-based analysis.

Analysis of clinical and molecular associations of triple negative breast cancers in node-negative patients

INTRODUCTION

Therapeutic modalities in node-negative breast cancer patients remain a matter of controversy. Various prognostic factors have been proposed to help select those patients that would most likely benefit from adjuvant therapy. In view of this notion the triple negative phenotype (hormone receptors and HER2 negative tumors) has gained increasing attention.

AIM

To evaluate the clinicopathologic characteristics of triple negative (TN) tumors in node-negative invasive breast carcinomas.

METHODS

We retrospectively analyzed the archival pathology tissues of 160 patients with node-negative invasive carcinomas, diagnosed and treated in two surgical departments in Greece from 1999 to 2006. Statistical analysis was used to examine the association between TN tumors and other clinicopathological factors.

RESULTS

Triple negative breast cancers correlated with higher histologic grade, mitotic activation index and Ki-67 expression (p < 0.05). Moreover TN tumors were correlated with negative staining for bcl-2 (p < 0.05).

CONCLUSION

In node-negative breast cancer patients, triple negativity is associated with aggressive biologic behavior. Further studies are required to better understand the clinical implications of these findings.

The value of proliferation indexes in breast cancer

INTRODUCTION

During the past several years, the Ki-67 antigen has gathered great interest in its role as a prognostic marker. Nevertheless, despite the large number of published papers, the role of Ki-67 in clinical practice remains controversial.

AIM

To evaluate the association between Ki-67 immunoreactivity and other clinicohistopathological parameters.

METHODS

We retrospectively analyzed the archival pathology tissues of 356 patients, diagnosed and treated in our department, from 2002 to 2006. Statistical analysis was used to examine the association between Ki-67 expression and other clinicopathological factors.

RESULTS

The expression of Ki-67 was correlated with the mitotic count, tumor grade and size and p53, HER2 and EGFR expression. Furthermore Ki-67 expression was significantly related with nodal status and inversely associated with hormonal expression. Moreover, invasive carcinomas appeared to have greater proliferation values than in situ carcinomas, while invasive ductal carcinomas were correlated with higher Ki-67 expression compared to lobular cancers.

CONCLUSION

The expression of Ki-67 appears to be a valuable method of proliferation measurement that could prove helpful in clinical practice. Further research is warranted in order to standardize the methodology and to reach uniformity in regard with the optimal cut-off value.

High-resolution contrast-enhanced, susceptibility-weighted MR imaging at 3T in patients with brain tumors: correlation with positron-emission tomography and histopathologic findings

BACKGROUND AND PURPOSE

The purpose of this work was to demonstrate susceptibility effects (SusE) in various types of brain tumors with 3T high-resolution (HR)-contrast-enhanced (CE)-susceptibility-weighted (SW)-MR imaging and to correlate SusE with positron-emission tomography (PET) and histopathology.

MATERIALS AND METHODS

Eighteen patients with brain tumors, scheduled for biopsy or tumor extirpation, underwent high-field (3T) MR imaging. In all of the patients, an axial T1-spin-echo (SE) sequence and an HR-SW imaging sequence before and after IV application of a standard dose of contrast agent (MultiHance) was obtained. Seven patients preoperatively underwent PET. The frequency and formation of intralesional SusE in all of the images were evaluated and correlated with tumor grade as determined by PET and histopathology. Direct correlation of SusE and histopathologic specimens was performed in 6 patients. Contrast enhancement of the lesions was assessed in both sequences.

RESULTS

High-grade lesions demonstrated either high or medium frequency of SusE in 90% of the patients. Low-grade lesions demonstrated low frequency of SusE or no SusE. Correlation between intralesional frequency of SusE and histopathologic, as well as PET, tumor grading was statistically significant. Contrast enhancement was equally visible in both SW and SE sequences. Side-to-side comparison of tumor areas with high frequency of SusE and histopathology revealed that intralesional SusE reflected conglomerates of increased tumor microvascularity.

CONCLUSIONS

3T HR-CE-SW-MR imaging shows both intratumoral SusE not visible with standard MR imaging and contrast enhancement visible with standard MR imaging. Because frequency of intratumoral SusE correlates with tumor grade as determined by PET and histopathology, this novel technique is a promising tool for noninvasive differentiation of low-grade from high-grade brain tumors and for determination of an optimal area of biopsy for accurate tumor grading.

Positron emission tomography with [18F]2-fluoro-D-2-deoxyglucose (FDG-PET) predicts relapse of malignant lymphoma after high-dose therapy with stem cell transplantation

We have determined the predictive value of [18F]2-fluoro-2-deoxy-glucose (FDG-PET) in patients with Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) scheduled for high-dose therapy with stem cell transplantation (HDT/SCT). Inclusion criteria were the presence of an FDG-PET scan after chemotherapy (ChT) within 8 weeks prior to HDT/SCT and available follow-up data. Sixteen patients (10 NHL and six HD) were observed during a follow-up period of 4 to 28 months (median 13 months). Before SCT, five patients had a negative PET, three were weakly positive, two moderately positive, and six strongly positive. None of the five patients with a negative PET before HDT/SCT relapsed and two of three patients with a weakly positive scan are still in remission after HDT/SCT. Of eight patients with a moderate or high positive PET before HDT/SCT, seven relapsed and one died of early HDT/SCT related complications (P< 0.01). Three of eight relapsing patients died of lymphoma 5 to 10 months after SCT and in one additional patient not responding to HDT/SCT, the main cause of death was chronic toxicity 4 months after transplantation. After 12 months, in PET-negative patients the overall and relapse-free survival was 100%, in PET-positive patients 55% and 18%, respectively. In NHL, two patients with negative PET, but with an age-adjusted international prognostic index (AaIPI) of 2 and one with AaIPI = 1 are still in remission. In the seven PET-positive subjects, one patient with AaIPI = 0, three with AaIPI = 1, and two with AaIPI = 2 relapsed. We conclude that FDG-PET is accurate in the prediction of relapse prior to HDT/SCT in patients with lymphoma. It provides additional information when compared with the AaIPI.

FDG-PET in adrenocortical carcinoma

Adrenal cortical carcinoma (ACC) is a rare malignant neoplasm with a poor prognosis. Radical surgery of the primary tumor and of local as well as of distant recurrence is the only effective treatment, and requires accurate and early localization of recurrent tumors. In this regard, we prospectively scanned 10 patients with ACC, 8 during follow-up and 2 at primary work-up. In all patients PET scans from the neck to the upper thighs were obtained 45 minutes after injection of 370 MBq [18F]FDG. Reading was done visually, with the investigator blinded to the results of other diagnostic modalities. All known sites of ACC lesions showed markedly increased FDG uptake. In 3 patients, previously unknown lesions were identified by PET in the lung (one lesion), the abdomen (3 lesions), and the skeleton (multiple), respectively. One false positive liver focus was shown by PET aside from the true positive lung metastases in the same patient. The sensitivity/specificity of PET based on different organs was 100/97%, that based on the number of PET-detected lesions (N = 23) was 100/95%. PET altered or influenced the tumor stage in 3/10 patients, modifying the subsequent therapeutic management in 2/10 patients. We conclude that FDG-PET is highly useful in ACC and should be included in the work-up for initial staging as well as for follow-up.

Radiation exposure from patients treated with 165Dy-ferric hydroxide

In radiation synovectomy about 10 GBq 165Dy-ferric hydroxide is injected into major joints. Measurements of the dose rates were performed at distances of 5 cm, 0.5 m, 1 m and 2 m from the surface of the treated joints (knees) until 200 min after the application in 16 patients in order to estimate the radiation exposure of persons in the neighbourhood of the patients. The highest doses were estimated for the fingers of the technologist (320 microSv) and for the physician (700 microSv). Special shields for the syringes were constructed for dose reduction. The whole-body doses were 103 microSv for the technologist and 40 microSv for the physician. After the discharge of the patient to a ward or home, other persons at 1 m distance from the patient might receive 88 microSv, which is less than 9% of the annual permissible dose. Our results clearly demonstrate that the calculated radiation exposure to personnel and family members is well below the maximum annual dose limit for non-professionally exposed persons.

Radioactive contamination of contact lenses during radioiodine therapy

Although the secretion of radioiodine in tears is not unexpected, there are only few investigations in that field. We report the measurement of 131I in disposable contact lenses for daily use during radioiodine treatment. After administration of 740 MBq 131I, all contact lenses of a 59-year-old female used the day before and 5 days after radioiodine therapy were collected and measured in a gamma counter. Activities of 124 Bq (right) and 139 Bq (left) were measured in the contact lenses used during the first day after administration of radioiodine. The activity in the contact lenses of the following days was significantly lower. An initial dose rate of approximately 0.31 microSv x h(-1) was caused by the radioactivity resulting in a total dose of 13 microSv to the patient's eye lens. That dose is negligible compared to the dose caused by the incorporated radioactivity.

Influence of drugs on myocardial iodine-123 metaiodobenzylguanidine uptake in rabbit myocardium

About 15 years ago, iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging was introduced for the evaluation of myocardial sympathetic nerve function. Two uptake mechanisms for MIBG have so far been identified: uptake type I, a saturable, energy-dependent mechanism, and uptake type II, a non-saturable, energy-independent mechanism. We incubated isolated rabbit myocardial tissue samples with 123I-MIBG in order to assess the uptake characteristics and the influence of varying incubation conditions. Furthermore, we examined the effects of several drugs and uptake inhibitors on the myocardial uptake of MIBG. The in vitro myocardial uptake of MIBG reached a steady plateau at 23.87%+/-3.63% after 1 h, i.e. a concentration gradient of 10, in a thermo-independent manner within a concentration range from 1.5 to 1500 microM. This indicates an unsaturable uptake process in the tested concentrations. Preincubation with the following drugs caused a significant inhibitory effect on myocardial MIBG uptake: haloperidol, levomepromazine, metoprolol, labetalol and clomipramine. According to our findings, the uptake mechanism seems to be an unspecific process, but the concentration gradient of 10 makes passive diffusion unlikely. Further studies with uptake-II-blocking substances as well as with isolated myocardial cells will be needed to clarify the nature of the myocardial MIBG uptake mechanism.

The economy class syndrome--a survey of 19 cases

BACKGROUND

Thromboembolic events during or immediately after long-distance flights (economy class syndrome--ECS) are gaining more importance due to the rapidly increasing number of flights. Systematic data on haemostatic parameters in these patients are not available yet.

PATIENTS AND METHODS

We were therefore analyzing the anamnestic, laboratory and clinical findings in 19 patients (17 males, 2 females, aged 33-75 years) with the final clinical diagnosis ECS.

RESULTS

Symptoms commenced either immediately or up to 93 hours after disembarkation (mean 42.3 hours). In the great majority (84.2%) myocardial infarction was the initial diagnosis. No defect in the coagulation and/or prostaglandin system was discovered in either of the patients. Prevalence of smoking (26.3%) was even lower than in the normal population. No predisposing factors were found. Apparent anamnestic similarities were flu and fever (47.4%) while 4 of the patients (26.3%) had severe diarrhoea and dehydration before the flight. Almost all the patients (78.9%) were drinking alcohol during the flight and not actively moving their legs (84.2%). ECS occurred also in business and first class passengers.

CONCLUSION

Surprisingly the onset of ECS is definitely not associated with haemostatic defects and not necessarily associated with the clinical risk factors reported.

Examination of co-complexes for radiolabeling of platelets in positron emission tomographic studies

Oxine, tropolonate, and mercaptopyridine-N-oxide (MPO) have been widely used with 111In for platelet labeling. The use of positron emission tomography (PET) radioisotopes for platelet labeling would offer a higher sensitivity and resolution over conventional imaging. The medium half-life PET radioisotope 55Co (t1/2 = 18.2 hours) would enable quantitative uptake and cell kinetic studies with radiolabeled platelets. To identify the optimal complex for radiolabeling of platelets with 55Co, we investigated the platelet uptake of 57Co-oxine, 57Co-tropolonate, and 57Co-MPO in varying different parameters. The platelet uptake of Co-complexes was generally low (5-12%), dependent on time and temperature of incubation and density of platelets but independent of the amount of radioactivity. These findings are not promising for potential PET application.

99m-Tc-tetrofosmin scintigraphy and breast cancer

BACKGROUND

99m-Tc-tetrofosmin holds significant interest among medical oncologists because of its high positive predictive value (>90%) in pilot trials, exceeding sensitivity and specificity rates of mammography. Objective. Our objective was to assess the diagnostic accuracy of 99m-Tc-tetrofosmin whole-body scintigraphy in outpatients.

PATIENTS AND METHODS

Thirty-one patients with an abnormal mammograph (n = 22) or follow-up patients (n = 9), 7 of whom were known to have metastatic disease, were included. Tracer (550 MBq) was injected into the cubital vein. Whole-body planar and single photon emission computed tomography images of regions of interest were obtained. Histology, computed tomography (CT), or magnetic resonance imaging (MRI) were performed to confirm scintigraphic results. Correlation between scintigraphy and CT or MRI was assessed by two independent radiologists. Accuracy, sensitivity, and specificity rates for the diagnosis of local and distant breast cancer lesions were given.

RESULTS

Of the 22 first-visit patients, 15 had breast cancer, and 7 had no evidence of any malignant disease. Of all patients examined (n = 31), 21 had distant metastases. Breast tumors were correctly diagnosed in 14/15 patients (93%), with only 1 false-negative result. Extrahepatic metastatic lesions (n = 16) were correctly diagnosed in 14 (88%) patients, whereas the method was not suitable for the diagnosis of liver metastases.

CONCLUSION

Tetrofosmin scintigraphy has shown very high detection rates of breast tumors and of metastatic lesions and is therefore a valuable option in breast cancer diagnosis.

Platelet labeling with 67Ga chelates

68Ga-labeled platelets could be useful for positron emission tomographic (PET) studies. In order to identify the optimal chelate for radiolabeling of platelets with 68Ga, we investigated the platelet uptake of 67Ga-oxine, -tropolone and -MPO. The platelet uptake of 67Ga-oxine and -tropolone is very low (< 5%). The platelet uptake of 67Ga-MPO, in contrast, increases with platelet density (highest at 10(9) platelets/ml) up to 18%. Our data provide evidence that only 68Ga-MPO could be useful for PET-studies.

6-Oxo-PGF1alpha and 8-epi-PGF2alpha in human atherosclerotic vascular tissue

Isoprostanes are a new family of compounds generated by the free radical catalyzed action on arachidonic acid. Formed during oxidation they have been claimed to be a reliable indicator of in vivo oxidation injury. We assessed the amount of 8-epi-PGF2alpha in human surgical specimens as compared to PGI2 (via its stable metabolite 6-oxo-PGF1alpha), the major compound generated by vascular tissue. 8-epi-PGF2alpha is low in normal vascular tissue as is the 8-epi-PGF2alpha/6-oxo-PGF1alpha ratio. The vessels of smokers in general exhibited an increased 8-epi-PGF2alpha (r=0.82) and a decreased 6-oxo-PGF1alpha (r=0.71). The 8-epi-PGF2alpha/6-oxo-PGF1alpha ratio is, not significantly, increased in vessels derived from hyperlipidemics and hypertensives. These findings indicate that lipid peroxidation occurs within the human arterial wall as evidenced by 8-epi-PGF2alpha, probably further decreasing the synthesis of PGI2 and promoting atherogenic mechanisms.

Technetium-99m-tetrofosmin: a new agent for melanoma imaging?

The aim of our study was to examine whether technetium-99m 1,2-bis[bis(2-ethoxyethyl) phosphino]ethane (tetrofosmin) a lipophilic, cationic tracer which was first developed for myocardial perfusion imaging, could be a new radiopharmaceutical for melanoma imaging. We therefore used two human cell lines, SK-MEL 28 and 5i8 A2 (n = 6, cell concentration 106/ml, incubation at 22 degrees C and 37 degrees C, 50-100 approximately lCi/ml Tc-99m-tetrofosmin, time of incubation 10-180 minutes). The cellular uptake by both cell lines was determined. In contrast to another non- melanoma tumor cell line MCF-7 (a human adenocarcinoma breast cancer) which reached steadystate almost immediately (within 10 minutes), the cellular uptake of SK-MEL-28 increased after 60 minutes and showed a very high uptake (> 10%) after 120 minutes and decreased after 180 minutes (6-8%), while the uptake in 518 A2 cells was about 5% after 90 minutes. Our data show that Tc-99m-tetrofosmin could be a promising agent for melanoma imaging.

Passive smoking and platelet thromboxane

While active smoking is known to enhance platelet thromboxane production, no data on passive smoking is available yet. The influence of single and repeated exposure to passive smoke for 60 minutes in a 18 m3 room was assessed in non-smokers as compared to sex and age matched smokers. All the evaluated measures (malondialdehyde, plasma thromboxane B2, 11-dehydro-thromboxane B2, serum thromboxane B2, conversion of exogenous arachidonic acid to thromboxane B2 and to hydroxy-5, 8,10-heptadecatrienoic acid) were higher in smokers than non-smokers at baseline, immediately and 6 hours after passive exposure to cigarette smoke. Repeated exposure of non-smokers rendered their platelets more activated becoming close to the behaviour of smokers. These results indicate that passive smoking may activate thromboxane A2 release from the platelets, contributing to the development of hemostatic imbalance.