Multimodal Imaging of Patients With Gliomas Confirms 11C-MET PET as a Complementary Marker to MRI for Noninvasive Tumor Grading and Intraindividual Follow-Up After Therapy

The value of combined L-( methyl-[¹¹C]) methionine positron-emitting tomography (MET-PET) and magnetic resonance imaging (MRI) with regard to tumor extent, entity prediction, and therapy effects in clinical routine in patients with suspicion of a brain tumor was investigated. In n = 65 patients with histologically verified brain lesions n = 70 MET-PET and MRI (T1-weighted gadolinium-enhanced [T1w-Gd] and fluid-attenuated inversion recovery or T2-weighted [FLAIR/T2w]) examinations were performed. The computer software "visualization and analysis framework volume rendering engine (Voreen)" was used for analysis of extent and intersection of tumor compartments. Binary logistic regression models were developed to differentiate between World Health Organization (WHO) tumor types/grades. Tumor sizes as defined by thresholding based on tumor-to-background ratios were significantly different as determined by MET-PET (21.6 ± 36.8 cm³), T1w-Gd-MRI (3.9 ± 7.8 cm³), and FLAIR/T2-MRI (64.8 ± 60.4 cm³; P < .001). The MET-PET visualized tumor activity where MRI parameters were negative: PET positive tumor volume without Gd enhancement was 19.8 ± 35.0 cm³ and without changes in FLAIR/T2 10.3 ± 25.7 cm³. FLAIR/T2-MRI visualized greatest tumor extent with differences to MET-PET being greater in posttherapy (64.6 ± 62.7 cm³) than in newly diagnosed patients (20.5 ± 52.6 cm³). The binary logistic regression model differentiated between WHO tumor types (fibrillary astrocytoma II n = 10 from other gliomas n = 16) with an accuracy of 80.8% in patients at primary diagnosis. Combined PET and MRI improve the evaluation of tumor activity, extent, type/grade prediction, and therapy-induced changes in patients with glioma and serve information highly relevant for diagnosis and management.

High-activity samarium-153-EDTMP therapy followed by autologous peripheral blood stem cell support in unresectable osteosarcoma

Purpose: Despite highly efficacious chemotherapy, patients with osteosarcomas still have a poor prognosis if adequate surgical control cannot be obtained. These patients may benefit from therapy with radiolabeled phosphonates. Patients and Methods: Six patients (three male, three female; seven to 41 years) with unresectable primary osteosarcoma (n = 3) or unresectable recurrent sites of osteosarcomas (n = 3) were treated with high-activity of Sm-153-EDTMP (150 MBq/kg BW). In all patients autologous peripheral blood stem cells had been collected before Sm-153-EDTMP therapy. Results: No immediate adverse reactions were observed in the patients. In one patient bone pain increased during the first 48 hrs after therapy. Three patients received pain relief. Autologous peripheral blood stem cell reinfusion was performed on day +12 to +27 in all patients to overcome potentially irreversible damage to the hematopoietic stem cells. In three patient external radiotherapy of the primary tumor site was performed after Sm-153-EDTMP therapy and in two of them polychemotherapy was continued. Thirty-six months later one of these patients is still free of progression. Two further patients are still alive. However, they have developed new metastases. The three patients who had no accompanying external radiotherapy, all died of disease progression five to 20 months after therapy. Conclusion: These preliminary results show that high-dose Sm-153-EDTMP therapy is feasible and warrants further evaluation of efficacy. The combination with external radiation and polychemotherapy seems to be most promising. Although osteosarcoma is believed to be relatively radioresistant, the total focal dose achieved may delay local progression or even achieve permanent local tumor control in patients with surgically inaccessible primary or relapsing tumors.

Einsatz der FDG-PET bei der Diagnostik des zentralnervösen Lupus erythematodes und Vergleich mit CT und MRI

Central nervous system involvement has been found in 30-75% of all cases of systemic lupus erythematosus (SLE). Up to now, clinical diagnosis is difficult and there are no markers for disease activity. We have compared cranial computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) using fluorodesoxyglucose (FDG) in two cases. FDG-PET is shown to be the most sensitive method demonstrating even reversible deficits and a better correlation with other neurological findings. MRI seems to be more sensitive than CT. A survey of the literature concerning imaging methods in neuropsychiatric SLE is given. The special problem of neuronal desactivation by antineuronal activity is discussed.

201TI Reinjection Predicts Improvement of Left Ventricular Function following Revascularization

The aim of this study was to evaluate the correlation between improved TI uptake in reinjection imaging with improvements in regional wall motion and global ejection fraction following PTCA or aorto-coronary bypass surgery. 19 patients with CHD were investigated and divided into two groups according to their thallium uptake in the reinjection studies. Group I showed additional uptake on reinjection imaging compared to the redistribution image, whereas group II showed no additonal uptake. Both groups had a similar number and distribution of affected vessels and location of the leading stenosis. Stress, redistribution and reinjection images were obtained prior to revascularization and evaluated semiquantitatively from a bulls eye scheme. There was a postoperative increase in regional wall motion in group I from 5.3 to 8.8% whereas group II did not show a relevant change (6.3 vs 6.0%). The ejection fraction increased from 55.0 to 66.7% in group I and dit not increase in group II (59.8 vs 58.7%). The overall predictive value of the reinjection image for improvement in wall motion (> 10%) was 91 % and for the redistribution image 58%. Increased uptake in reinjection imaging predicts improved ventricular function following revascularization and indeed indicates viable myocardium with reversible functional impairment.

Basics and Recommendations for Brain SPECT

In diesem Artikel werden von der Arbeitsgruppe »Neurologie« der Europäischen Gesellschaft für Nuklearmedizin (EANM) Richtlinien für die SPECT des Gehirns gegeben. In den einzelnen Kapiteln werden die pathophysiologischen Grundlagen verschiedener Krankheiten des Gehirns, die Pharmakokinetik und -dynamik verschiedener Radiopharmaka, die physikalischen Grundlagen, die computerisierte Datenverarbeitung, die klinischen Aufzeichnungen und die Auswertung der SPECT-Ergebnisse besprochen.

Rezidivnachweis eines Glomus-caroticum-Tumors mit der Somatostatin-Rezeptor-Szintigraphie

Der Glomus-caroticum-Tumor gehört zu den nicht chromaffinen Para-gangliomen. Aufgrund der geringen Inzidenz mit 1% im Kollektiv einer gefäßchirurgischen Abteilung wird präoperativ nur in 10-20% der Fälle die richtige Diagnose gestellt. Für das chirurgische Vorgehen ist der frühzeitige Nachweis des Primär- oder Rezidiv-Tumors von entscheidender Bedeutung. Bei fortgeschrittenem Tumor-Stadium, z.B. mit Einbeziehung der A. carotis in den Tumorprozeß, steigt die perioperative Mortalität. Außerdem treten als Komplikation häufig Nervenläsionen durch die chirurgische Tumor-Resektion auf. Diese Kasuistik zeigt die Bedeutung der Somatostatin-Rezeptor-Szintigraphie bei der Differenzierung von Glomus-caroticum-Tumor-Rezidiv und postoperativen Narben, die mit röntgenologischen Verfahren Schwierigkeiten bereiten kann. Bei der hier vorgestellten Patientin bestand klinisch schon seit 2 Jahren ein Rezidivverdacht, der jedoch damals durch MRT und Angiographie nicht verifiziert werden konnte.

Rezidiv eines Neuroblastoms Stadium IV

Bei der Verlaufskontrolle des metastasierenden Neuroblastoms ist die mlBG-Szintigraphie unbestritten das szintigraphische Verfahren der Wahl. Anhand des Krankheitsverlaufes eines Kindes mit metastatischem Rezidiv eines Neuroblastoms wird gezeigt, daß ein Rezidiv trotz eindeutiger szintigraphischer Abbildung mit negativen Laborparametern einhergehen kann. Auch retrospektiv ist der Wert einer zusätzlich durchgeführten Knochenszintigraphie schwer beurteilbar.

Bedeutung von Lymphknotenmetastasen beim differenzierten Schilddrüsenkarzinom

464 Patienten mit differenziertem Schilddrüsenkarzinom wurden nach einem einheitlichen risikoorientierten Therapieschema mit frühzeitiger chirurgischer Reintervention einschließlich der kompartimentorientierten Lymphadenektomie bei Lymphknotenmetastasen und/oder lokalem Rezidiv, jedoch ohne routinemäßige externe Bestrahlung behandelt. Es bestand kein Einfluß einer Lymph-knotenmetastasierung auf die Überlebenswahrscheinlichkeit. Die Differenz in der Überlebenswahrscheinlichkeit zwischen Patienten mit (24%) und ohne (76%) Lymphknotenmetastasierung in der univariaten Analyse war durch die Koinzidenz der Faktoren höheres Tumorstadium (T4) und Fernmetastasierung (Mt) bedingt. Unter konsequenter Verwendung der frühzeitigen chirurgischen Reintervention mit kompartimentorientierter Lymphadenektomie ist ein Einschluß des Faktors N1 in die Risikostratifizierung hinsichtlich der Überlebenswahrscheinlichkeit nicht notwendig.

Immunszintigraphie des hä matopoetischen Knochenmarks bei Osteomyelofibrose

In planning the treatment of splenomegaly in primary or secondary osteomyelofibrosis it is necessary to know whether there is any significant hematopoiesis outside the spleen. In contrast to the measurement of iron kinetics with 59Fe, which is not suitable for imaging, immunoscintigraphy with the monoclonal antibody Bw 250/183 allows specific imaging of the hematopoietic bone marrow. The diagnostic use of this method in addition to iron kinetics is illustrated and discussed in a patient with primary osteomyelofibrosis.

PET and SPECT in Medically Non-Refractory Complex Partial Seizures

Ziel: Im Gegensatz zu den medikamentös-refraktären komplex-fokalen Epilepsien (CPS) wurden zerebrale Perfusion und Metabolismus bei Patienten mit nichtrefraktären Epilepsien kaum untersucht. Ziel dieser Studie war die Untersuchung der Häufigkeit temporaler Asymmetrien des regionalen zerebralen Glukoseverbrauchs (rCMRGIc), der regionalen zerebralen Perfusion (rCBF) und der regionalen zerebralen Benzodi- azepin-Rezeptordichte (BRD) bei dieser Patientengruppe. Methoden: Es wurden 49 Patienten mit medikamentös-nichtrefraktären, kryptogenen CPS untersucht (Alter: 36,0 ± 16,1 Jahre). Der rCMRGIc wurde mit F-18-FDG-PET (FDG), der rCBF mit Tc-99m-ECD-SPECT (ECD) und die BRD mit 1-123-Jomazenil-SPECT (IMZ) untersucht. Alle drei Untersuchungen wurden interiktual und binnen vier Wochen bei jedem Patienten durchgeführt. Die Dauer der Epilepsie betrug zwischen 0,1 und 42 Jahre (Median 4,0 Jahre). Die SPECT-Studien wurden mit der Dreikopfkamera Multispect 3, die PET-Studien mit dem PET-System ECAT EXACT 47 durchgeführt. Mit Hilfe von Linienprofilen wurden rCMRGIc, rCBF und BRD in vier temporalen Regionen bestimmt; die daraus errechneten Asymmetrie-Indizes (ASY) wurden mit den 95%-Konfidenzin- tervallen von Kontrollpersonen verglichen. Ergebnisse: Von den 49 Patienten wiesen 35 (71%) einen signifikant pathologischen ASY in mindestens einer Region auf; der rCMRGIc war asymmetrisch bei 41 % der Patienten, die BRD bei 29%, und der rCBF bei 24%. Bei einem Patienten waren alle drei Variablen pathologisch, bei zwei der rCMRGIc und die BRD, bei drei der rCMRGIc und der rCBF und bei vier weiteren Patienten der rCBF und die BRD. Eine isolierte Asymmetrie des rCMRGIc fand sich in 14, der BRD in 7 und des rCBF in 4 Fällen. Es gab keine Diskrepanzen in der Latéralisation zwischen den drei Methoden. Schlußfolgerung: Die Mehrzahl der Patienten mit medikamentös- nichtrefraktären CPS weist eine Abnormalität des rCMRGIc, der BRD oder des rCBF auf. In diesem Patientenkollektiv zeigt FDG-PET am häufigsten eine temporale Auffälligkeit.

Myocardial Perfusion and Metabolism After Transcoronary Ablation of Septum Hypertrophy (TASH) in Hypertrophic Obstructive Cardiomyopathy

Outflow obstruction constitutes a major problem in hypertrophic obstructive cardiomyopathy (HOCM) and may be treated by transcoronary injection of ethanol into septal arteries (transcoronary ablation of septum hypertrophy, TASH). We report on myocardial perfusion and glucose metabolism in a 50 year old man in whom TASH led to a reduction of septal thickness (9 vs. 26 mm), a sustained elimination of the outflow tract obstruction (resting gradient 0 vs. 60 mmHg; postES-gradient 10 vs. 145 mmHg) and a substantial clinical improvement (NYHA stage II vs. Il-lll) without impairment of global ventricular function (left ventricular ejection fraction 0.62 vs. 0.64). After TASH, perfusion and glucose metabolism were assessed by positron emission tomography (PET) using F-18-fluorodeoxyglucose (F-18-FDG) and Tc-99m-MIBI single photon emission tomography (SPECT). TASH results in matched reduction of perfusion and glucose consumption in a circumscribed area fed by the septal branch used for ethanol injection. No remote effects were observed. TASH leads to a sharply delineated septal reduction of perfusion and metabolism with consecutive reduction of septal thickness, a sustained elimination of the outflow tract obstruction, and a substantial clinical improvement without impairment of global ventricular function.

Costs of F-18-FDG PET: Experience with a satellite concept

Aim: One of the main arguments against the acceptance and introduction of FDG PET as a regular benefit in the statutory Medical Insurance system in Germany are its (alleged) high costs. The aim of the present study has been to determine empirically over a period of twelve months the costs of FDG PET, making use of a satellite concept. Methods: Documentation on performance and consumption data has been assembled for purposes of cost analysis. After analysis these data provided the basis for an assessment of the costs. In view of the high proportion of fixed overheads and strong fluctuations in consumption values, it was not possible to allocate reliably in an individual FDG PET investigation the various types of costs to individual causes. A monthly cost assessment procedure was therefore adopted. For this purpose data were recorded in the department for Nuclear Medicine, while the statistical assessment of the consumption data and analysis of the costs were undertaken in the Institute of Industrial and Hospital Management. Results: Over the twelve month observation period (November 1995 to October 1996, 177 working days) 433 patients were included in the study: 244 with brain diseases 37 cardiac patients, 130 whole body studies and 22 combined studies (brain and whole body scans). The non volume based costs, maintenance charges and depreciation accounted for the highest proportion of the total costs (48%). The FDG- related costs accounted for 41 % of the total costs, while the personnel costs amounted to 11% and the film costs to only 0.45%. The total costs incurred amounted to DM 1,205,050. Conclusion: These data represent a first empirical cost analysis for FDG PET based on a satellite concept and form a starting point for a cost/benefit analysis of this procedure.

Measurement of Temporal Asymmetries of Glucose Consumption Using Linear Profiles: Reproducibility and Comparison with Visual Analysis

Aim: One approach to regionally analyze temporal glucose consumption consists in drawing linear profiles over the maximal values measured in the temporal cortical ribbon. The aim of our study was to test the reproducibility of this method and to compare its diagnostic performance to that of visual analysis in patients with complex partial seizures (CPS). Methods: Regional cerebral glucose consumption (rCMRGIc) was measured interictally in 25 CPS patients and 10 controls using F-18-deoxyglucose and the positron emission tomography (PET) camera ECAT EXACT 47. The PET scans were visually analyzed for the occurrence of unilateral temporal hypermetabolism. Furthermore, rCMRGIc was quantified on six contiguous coronal planes by manually tracing maximal values of temporal glucose consumption, thus creating line profiles of temporal glucose consumption for each side. Indices of asymmetry (ASY) were then calculated from these line profiles in four temporal regions and compared to the corresponding 95% confidence intervals of the control data. All analyses were performed by two observers independently from each other and without knowledge of the clinical findings. Results: The agreement between the two observers with regard to focus lateralization was 96% (κ = 0.93) on visual analysis and 100% (κ = 1) on quantitative analysis. There was an excellent agreement with regard to focus lateralization between visual and quantitative evaluation (κ = 0.8). Conclusion: Quantitation of local temporal rCMRGIc by using linear profile analysis is highly reproducible; for the lateralization of epileptogenic foci, however, this method does not possess significant advantages over the visual evaluation of the scans.

D2-Rezeptorszintigraphie (123J-IBZM) im Vergleich zur zerebralen Perfusion (99mTc-HMPAO) bei extrapyramidalen Erkrankungen

Ziel der Studie war es, zu überprüfen ob eine Korrelation zwischen zerebraler Perfusion (99mTc-HMPAO) und D2-Rezeptorbindung (123J-IBZM) bei extrapyramidalen Erkrankungen besteht. 13 Patienten mit Parkinson-Syndrom und 13 Patienten mit extrapyramidalen Hyperkinesien wurden untersucht. Bei allen Patienten wurden SPECT-Studien mit 99mTc-HMPAO und 123J-IBZM im Abstand von 2 bis 7 Tagen durchgeführt. Die Auswertung erfolgte semiquantitativ zu Frontalhirn und Zerebellum als Referenzregion für die Basalganglien. Die Streuung der Quotienten Basalganglien/Referenz war in beiden Gruppen geringer, wenn das Frontalhirn als Referenz benutzt wurde. In der Gruppe der Patienten mit extrapyramidalen Hyperkinesien unterschieden sich die zwei Patienten mit Chorea Huntington durch ihre niedrigere Perfusion und die geringere D2-Rezeptorbindung in den Basalganglien von den übrigen Patienten mit extrapyramidalen Hyperkinesien. Es bestand keine Korrelation zwischen D2-Rezeptorbindung und regionalem zerebralen Blutfluß. Die Bestimmung der regionalen Perfusion bringt mit Ausnahme der Chorea Huntington keinen diagnostischen Zugewinn.

Verlaufskontrolle des Neuroblastoms Stadium IV: 123I-mIB G- Szintigraphie, Knochenszintigraphie und Katecholaminmetabolite

Ziel: Es soll die Wertigkeit von 123l-mlBG-Szintigraphie, Knochenszintigraphie und Katecholaminmetaboliten bei der Verlaufskontrolle untersucht werden. Methode: Es wurden 19 Kinder mit Neuroblastom im Stadium IV retrospektiv mit 123l-mlBG- und 99mTc-MDP-Szintigraphie untersucht und deren Ergebnisse mit der Bestimmung von Homovanillinsäure, Vanillinmandelsäure, neuronenspezifische Enolase, Laktat-dehydrogenase und Ferritin über einen Beobachtungszeitraum von 7-132 (Median: 36) Monaten verglichen. Ergebnisse und Schlußfolgerung: Die Ergebnisse zeigen, daß die Wertigkeit der einzelnen Verfahren vom Zeitpunkt des diagnostischen Einsatzes abhängig ist. Prinzipiell ist die mlBG-Szintigraphie das Verfahren mit der höchsten diagnostischen Aussagekraft. Zum prätherapeutischen Staging und zur Diagnostik des Rezidivs ist die Kombination aller drei Methoden sinnvoll. Bei der Verlaufskontrolle unter Chemotherapie spiegelt die mlBG-Szintigraphie die Heterogenität des Therapieeffektes am besten wider. Die Laborparameter eignen sich zum Therapiemonitoring wenig; der diagnostische Zugewinn durch die Skelettszintigraphie ist umstritten.

Costs of F-18-FDG PET with a Satellite Concept: Update

Aim: In an earlier study (study I) we had calculated the costs for FDG-PET investigations with our satellite concept (19). 433 patients were included in the study. Compared to the general indications for PET examinations the proportions of investigations were somewhat untypical: Both parameters have changed actually. Therefore we carried out a renewed data analysis (study II). Methods: All economic parameters were kept, in order to ensure the comparability of both studies. Only an adjustment of the costs to actual conditions was performed. Results: Proportions of investigations: Oncology 63%, Neurology 28%, Cardiology 9%; 3.5 investigations per working day. According to the increased number of investigations the structure of the total costs (DM 1601831) shows a small rise of the percentage costs for the FDG (41% to 42%) and a percentage decrease of the fixed overheads (48% to 43%). The percentage of personnel costs has increased (11% to 15%), the average cost per investigation has diminished: They amounted to DM 2783 in the earlier study (ranging from DM 2458 to 3463). The new data analy-sis results in the average cost of DM 2366 (-15%) per investigation (ranging from DM 2114 to 2840). Exemplary calculations show that a minimum of the costs will be achieved, if four investigations per day are performed. Retaining all parameters, which do not refer to the costs of the FDG, the average amount for one investigation would vary from DM 2000 (no delivery time) to DM 3300 (4 hours of delivery time). Conclusions: The results are in good agreement to the general laws of economic science, according to which an increase of the “number of units” with the same fixed overheads will result in a relative reduction of the costs of the “products”. A further increase in the frequency of investigations will lead to a rise of the average costs per investigation, because of the physical decay of the FDG delivered once a day.

Verfahrensanweisung für die nuklear medizinische Wächter-Lymphknoten-Diagnostik

The authors present a procedure guideline for scintigraphic detection of sentinel lymph nodes in malignant melanoma and other skin tumours, in breast cancer, in head and neck cancer, and in prostate and penile carcinoma. Important goals of sentinel lymph node scintigraphy comprise reduction of the extent of surgery, lower postoperative morbidity and optimization of histopathological examination focussing on relevant lymph nodes. Sentinel lymph node scintigraphy itself does not diagnose tumorous lymph node involvement and is not indicated when lymph node metastases have been definitely diagnosed before sentinel lymph node scintigraphy. Procedures are compiled with the aim to reliably localise sentinel lymph nodes with a high detection rate typically in early tumour stages. Radiation exposure is low so that pregnancy is not a contraindication for sentinel lymph node scintigraphy. Even with high volumes of scintigraphic sentinel lymph node procedures surgeons, theatre staff and pathologists receive a radiation exposure < 1 mSv/year so that they do not require occupational radiation surveillance.

Position paper nuclear cardiology: Update 2008

Nuclear cardiology is well established in clinical diagnostic algorithms for many years. This is an update 2008 of the first common position paper of the German Association of Nuclear Medicine and the German Association of Cardiology, Heart and Circulation Research published in 2001 aiming at an overview of state-of-the-art scintigraphic methods.

Clinical outcomes of adjuvant external-beam radiotherapy for differentiated thyroid cancer

Aim: Evaluate the clinical benefit of external beam radiotherapy (RTx) for locally invasive thyroid carcinoma with follicular cell differentiation (DTC). Patients, methods: The Multicentre Study on Differentiated Thyroid Cancer (MSDS) was planned as a prospective multicenter trial on the benefit of adjuvant RTx in locally invasive DTC (pT4; UICC 1997) with or without lymph node metastases and no known distant metastases. All patients were treated with thyroidectomy, 131I-therapy, and TSH-suppression and were randomized to receive additional RTx or not. In 4/2003 the trial became a prospective cohort study after only 45 of then 311 patients had consented to randomization. 351 of 422 patients met the trial's inclusion criteria. Age was 48 ± 12 years (mean ± SD). 25% were men. Tumours were papillary in 90% and follicular in 10%. Of 47 patients randomized or allocated to RTx, 26 actually received RTx. Results: Mean followup was 930 days. In an actual treatment analysis, 96% (25/26) of the RTx-patients reached complete remission (CR) vs. 86% in the non-RTx patients. Recurrences occurred in 0 vs. 3 % of patients: 6 reoperated for regional lymph node metastases, 1 tracheal invasion treated with tracheoplasty, 1 local invasion necessitating laryngectomy, 2 distant metastases (1 lung, 1 lung + bone). Serious chronic RTx toxicity occurred in 1/26 patients. Conclusion: The MSDS trial showed low mortality and recurrence rates and a weak benefit of RTx in terms of local control that did however not reach statistical significance. Routine RTx in locally invasive DTC can no longer be recommended .

Should all patients with thyroid nodules ≥ 1 cm undergo fine-needle aspiration biopsy?

The prevalence of thyroid nodules . 1 cm is high in a previously iodine-deficient area. Under the hypothesis, that all patients with such nodules undergo fine-needle aspiration biopsy (FNAB) and that sensitivity and specificity of cytology are calculated with 85%, the positive predictive value of pathologic cytologic finding will reach 1.5% only according to Bayes-theorem. This is clinically unacceptable, as resection will be the consequence in all cases with suspect cytology. Even implementation of a second, independent test (e. g. moleculargenetic testing of thyreocytes, sensitivity to detect mutation 50%, specificity 95%) and application of sequential Bayestheorem the positive predictive value of combined pathologic findings will increase to 13% only. Nevertheless, 58% out of all thyroid cancer remain undetected by such a sequential algorithm.

As a consequence, pre-selection of thyroid nodules for FNAB is required to increase the pretest-probability to at least 5.10%. A combination of sonographic criteria and scintigraphy, even in patients with normal TSHlevels, is suited to selected thyroid nodules for FNAB.

Jodinduzierte T3- Hyperthyreose beim metastasierenden follikulären Schilddrüsenkarzinom

Thyroid carcinoma is not a common disorder but the metastatic thyroid carcinoma manifesting thyrotoxicosis is exceedingly rare. Since Leiter et al. described the first patient with adenocarcinoma of the thyroid with functioning metastases and postoperative thyrotoxicosis in 1946, about 20 such cases have been reported. We have examined two cases of metastatic follicular thyroid carcinoma with T3-hyperthyroidism after surgical ablation of the gland. The thyrotoxicosis was induced by excessive iodine contamination during preoperative radiological examination.

Guidelines on radioiodine therapy for differentiated thyroid carcinoma

Aim: For the examination of the impact on clinical practice of the guidelines for differentiated thyroid carcinoma (DTC), treatment data from the ongoing Multicenter Study Differentiated Thyroid Carcinoma (MSDS) were analyzed. Patients, methods: Patients were randomized to adjuvant external beam radiotherapy (RTx) or no RTx in addition to standard therapy in TNM stages pT4 pN0/1/x M0/x (UICC, 5th ed. 1997). All patients were to receive the same treatment regimen consisting of thyroidectomy, ablative radioiodine therapy (RIT), and a diagnostic 131I whole-body scintigraphy (WBS) 3-4 months after RIT. Results: Of 339 eligible patients enrolled between January 2000 and March 2004, 273 could be analyzed. Guideline recommendations by the German Society for Nuclear Medicine from 1999 and 1992 were complied with within 28% and 82% with regard to the interval between surgery and RIT (4 vs. 4–6 weeks), in 33% and 84% with regard to 131I activity for RIT (1-3 vs. 1-4 GBq; ± 10%), and in 16% and 60% with regard to 131I activity for WBS (15319-300 vs. 15319-400 MBq; ± 10%). Conclusions: The 1999 guideline revision appears to have had little impact on clinical practice. Further follow-up will reveal if guideline compliance had an effect on outcomes.

Guideline for in vivo- and in vitro procedures for thyroid diseases (version 2)

The version 2 of the guideline for diagnostic standards of thyroid disorders is an update of the guideline published in 1999 and describes standards of in vitro and in vivo procedures. The following statements are modified: In vitro procedures: When measurement of the TSH-receptor antibodies is indicated, the guideline recommends the use of a second generation assay (recombinant human TSH-receptor as antigen). The functional assay sensitivity for the measurement of thyroglobulin should reach a value ≤1 ng/ml. Moleculargenetic tests (RET proto-oncogen) are indicated in patients with a newly diagnosed medullary thyroid cancer and in the relatives of patients with hereditary medullary thyroid cancer. In vivo procedures: The sonographic examination should use a probe with a frequency of at least 7.5 MHz. Indications for the thyroid scintigraphy: nodule size ≥1 cm in diameter, autonomous goitre/nodule with clinical or subclinical hyperthyroidism, necessity of a differentiation between Graves’ disease and chronic lymphocytic thyroiditis, therapy control after a definitive treatment and – in individual cases – the follow-up of untreated autonomous nodules.

Motion correction in PET/CT

Motion in PET/CT leads to artifacts in the reconstructed PET images due to the different acquisition times of positron emission tomography and computed tomography. The effect of motion on cardiac PET/CT images is evaluated in this study and a novel approach for motion correction based on optical flow methods is outlined. The Lukas-Kanade optical flow algorithm is used to calculate the motion vector field on both simulated phantom data as well as measured human PET data. The motion of the myocardium is corrected by non-linear registration techniques and results are compared to uncorrected images.

Guideline for radioiodine therapy for benign thyroid diseases (version 3)

The version 3 of the guideline for radioiodine therapy for benign thyroid diseases presents first of all a revision of the version 2. The chapter indication for radioiodine therapy, surgical treatment or antithyroid drugs bases on an interdisciplinary consensus. The manifold criteria for decision making consider the entity of thyroid disease (autonomy, Graves’ disease, goitre, goitre recurrence), the thyroid volume, suspicion of malignancy, cystic nodules, risk of surgery and co-morbidity, history of subtotal thyroidectomy, persistent or recurrent thyrotoxicosis caused by Graves’ disease including known risk factors for relapse, compression of the trachea caused by goitre, requirement of direct therapeutic effect as well as the patient’s preference. Because often some of these criteria are relevant, the guideline offers the necessary flexibility for individual decisions. Further topics are patients’ preparation, counseling, dosage concepts, procedural details, results, side effects and follow-up care. The prophylactic use of glucocorticoids during radioiodine therapy in patients without preexisting ophthalmopathy as well as dosage and duration of glucocorticoid medication in patients with preexisting ophthalmopathy need to be clarified in further studies. The pragmatic recommendations for the combined use of radioiodine and glucocorticoids remained unchanged in the 3rd version.

Staging in childhood lymphoma

Aim: The clinical value of positron emission tomography using fluorine-18 fluoro-deoxy-glucose (FDG-PET) in the staging of adult lymphoma has been shown in many studies. However, there are only few data regarding childhood lymphoma. The purpose of this retrospective study was to compare the staging of childhood lymphoma using FDG-PET and the established computed tomography (CT). Method: Whole-body FDG-PET was performed in 25 children with histologically proven Hodgkin ´s disease (n = 18) and non-Hodgkin´s lymphoma (n = 7) using a dedicated PET. The findings were compared with the CT results. Both examinations, FDG-PET and CT, were assessed by two experienced physicians. In each patient, 30 regions were analysed (22 nodal, 8 extranodal). Each region was assessed using a fivevalue scale (definitely/probably positive, equivocal, probably/definitely negative). Results: 662 regions (470 nodal, 192 extranodal) were compared. 91 regions (81 nodal, 10 extranodal; 14%) were concordant positive and 517 regions (347 nodal, 170 extranodal; 78%) were concordant negative. In 47 regions, 48 discordant findings (7%) were described: 27 findings (22 nodal, 5 extranodal) were positive using FDG-PET and negative using CT whereas 21 findings (17 nodal, 4 extranodal) were positive using CT and negative using PET. A total of 7 regions (1%) were judged equivocal in one imaging modality (1 FDG-PET, 6 CT). Using FDG-PET as compared to CT, resulted in a higher staging in 4 of 25 patients and in a lower staging in 2 of 25 patients. Conclusion: Staging of childhood lymphoma using FDGPET shows differences compared with CT resulting in a different staging in 6 of 25 patients. Prospective studies are required to evaluate the impact of these discrepancies on the clinical management of pediatric patients.

Clinical value of amino acid imaging in paediatric brain tumours

Purpose: To evaluate single photon emission computed tomography (SPECT) using the amino acid l-3-[123I]-α-methyl tyrosine (IMT) and contrast enhanced magnetic resonance imaging (MRI) as diagnostic tools in primary paediatric brain tumours in respect of non-invasive tumour grading. Patients, materials, methods: 45 children with primary brain tumours were retrospectively evaluated. IMT uptake was quantified as tumour/nontumour- ratio, a 4-value-scale was used to measure gadolinium enhancement on contrast enhanced MRI. Statistical analyses were performed to evaluate IMT uptake and gadolinium enhancement in low (WHO I/II) and high (WHO III/ IV) grade tumours and to disclose a potential relationship of IMT uptake to disruption of blood brain barrier as measured in corresponding MRI scans. Results: IMT uptake above background level was observed in 35 of 45 patients. IMT uptake was slightly higher in high grade tumours but the difference failed to attain statistical significance. Grading of individual tumours was neither possible by IMT SPECT nor by gadolinium enhanced MRI. Conclusion: IMT is accumulated in most brain tumours in children. Tumour grading was not possible using IMT or contrast enhancement as determined by MRI. Neither morphological nor functional imaging can replace histology in paediatric brain tumours.

1-123-Iodo-α-methyl tyrosine SPECT in non-parenchymal brain tumours

Purpose: Scintigraphy using I-123-iodo-α-methyl tyrosine (IMT) is useful in the preoperative characterization of gliomas, in detecting recurrent glioma and in the biological re-evaluation of residual or recurrent tumours. A systematic evaluation of non-parenchymal brain tumours has not yet been performed. The aim of the present study was to evaluate IMT SPECT in the management of intracerebral metastases and lymphomas. Patients and methods: IMT uptake was analyzed in 31 patients with 28 metastases of extracerebral solid tumours and 7 cerebral lymphomas. Histology revealed high grade lymphomas, melanomas, and carcinomas of the following origin: lung, unknown primary, breast, colon, renal cell, ovary, vagina, frontal sinus. IMT uptake was quantified as ratio between maximal tumour accumulation and average uptake in the contralateral hemisphere. Results: All tumours except two renal cell and one small cell lung carcinoma metastases accumulated IMT (91%). The highest IMT uptake was found in a metastasis of lung carcinoma. IMT uptake was highly variable and was similar in primary and in recurrent tumours. Conclusion: Significant accumulation of IMT is seen in the majority of tumours, so that this technique might be helpful for the management of cerebral metastases and lymphomas.

High non-specific binding of the β1-selective radioligand 2-125I-ICI-H

Aim: As results of cardiac biopsies suggest, myocardial β1-adrenoceptor density is reduced in patients with chronic heart failure. However, changes in cardiac β2-adrenoceptors vary. With suitable radiopharmaceuticals single photon emission computed tomography (SPECT) and positron emission tomography (PET) offer the opportunity to assess β-adrenoceptors non-invasively. Among the novel racemic analogues of the established β1-selective adrenoceptor antagonist ICI 89.406 the iodinated 2-I-ICI-H showed high affinity and selectivity to β1-adrenoceptors in murine ventricular membranes. The aim of this study was its evaluation as a putative sub-type selective β1-adrenergic radioligand in cardiac imaging. Methods: Competition studies in vitro and in vivo were used to investigate the kinetics of 2-I-ICI-H binding to cardiac β-adrenoceptors in mice and rats. In addition, the radiosynthesis of 2-125I-ICI-H from the silylated precursor 2-SiMe3-ICI-H was established. The specific activity was 80 GBq/µmol, the radiochemical yield ranged from 70 to 80%.

Results: The unlabelled compound 2-I-ICI-H showed high β1-selectivity and -affinity in the in vitro competition studies. In vivo biodistribution studies apparently showed low affinity to cardiac β-adrenoceptors. The radiolabelled counterpart 2-125I-ICI-H showed a high degree of non-specific binding in vitro and no specific binding to cardiac β1-adrenoceptors in vivo. Conclusion: Because of its high non-specific binding 2-125I-ICI-H is no suitable radiotracer for imaging in vivo.

Procedure guidelines for radioiodine therapy of differentiated thyroid cancer (version 2)

The procedure guidelines for radioiodine therapy (RIT) of differentiated thyroid cancer (version 2) are the counterpart to the procedure guidelines for 131I whole-body scintigraphy (version 2) and specify the interdisciplinary guidelines for thyroid cancer of the Deutsche Krebs-gesellschaft and the Deutsche Gesellschaft für Chirurgie concerning the nuclear medicine part. Compared with version 1 facultative options for RIT can be chosen in special cases: ablative RIT for papillary microcarcinoma ≤1 cm, ablative RIT for mixed forms of anaplastic and differentiated thyroid cancer, and RIT in patients with a measurable or increasing thyroglobulin concentration but without detectable metastases by imaging. The description of the pretherapeutic dosimetry now includes the isotopes 123I and 124I as well as a broader range of the activity of 131I. Activities of 2-5 GBq 131I are recommended for the first ablative RIT. If high accumulative activities of 131I are expected, men who have not yet finished their family planning should be advised to the option of sperm cryoconservation. An interdisciplinary consensus is necessary whether the new TNM-classification (UICC, 6th edition, 2002) will lead to modified recommendations for surgical or nuclear medicine therapy, especially for the surgical completeness and for the ablative RIT of pT1 papillary cancer.

Radioligands for imaging myocardial α- and β-adrenoceptors

Alpha- and beta-adrenoceptors play an important role in the control of heart function. According to their molecular, biological, and pharmacological characteristics, they are subdivided into α1-, α2- and β1-, β2-, β3-, β4-adrenoceptors. In cardiac disease, there is often a selective downregulation of β1-adrenoceptors associated with a relative increase in β2- and α1-adrenoceptors. Functional imaging techniques like single-photon emission tomography (SPECT) and positron emission tomography (PET) provide the unique capability for non-invasive assessment of cardiac adrenoceptors. Radioligands with high specific binding to cardiac α- and β-adrenoceptors suitable for radiolabelling are required for clinical studies. The non-selective β-adrenoceptor antagonist [11C]CGP-12177 was used to quantify β-adrenoceptor density using PET in patients with heart disease. New non-selective ligands (e. g. [11C]CGP-12388, [18F]CGP-12388, [11C]carazolol and [18F]fluorocarazolol) are currently evaluated; β1-selective radioligands (e. g. [11C]CGP-26505, [11C]bisoprolol, [11C]HX-CH 44) and β2-selective radioligands (e. g. [11C]formoterol, [11C]ICI-118551) were assessed in animals. None of them turned out as suitable for cardiac PET.

Potential radioligands for imaging cardiac α1-adrenoceptors are based on prazosin. Whereas [11C]prazosin shows low specific binding to myocardium, its derivative [11C]GB67 looks more promising. The putative α2-adrenoceptor radioligand [11C]MK-912 shows high uptake in rodent myocardium but has not yet been evaluated in man.

A number of radioligands were evaluated for assessing cardiac adrenoceptors using PET. New radioligands are needed to provide more insight into cardiac pathophysiology which may influence the therapeutic management of patients with cardiovascular disease.

Iodine excretion during stimulation with rhTSH in differentiated thyroid carcinoma

Aim: Elevated iodine intake is a serious problem in the diagnostic and therapeutic application of 131iodine in patients with differentiated thyroid cancer. Therefore, iodine avoidance is necessary 3 months in advance. Additionally, endogenous stimulation requires withdrawal of thyroid hormone substitution for 4 weeks. Exogenous stimulation using recombinant human TSH (rhTSH) enables the continuous substitution of levothyroxine, which contains 65.4% of its molecular weight in iodine. Thus, a substantial source of iodine intake is maintained during exogenous stimulation. Although this amount of stable iodine is comparable to the iodine intake in regions of normal iodine supply, it may reduce the accumulation of radioiodine in thyroid carcinoma tissue. The aim of this study was to assess the iodine excretion depending on different ways of stimulation. Methods: Iodine excretion was measured in 146 patients in the long term follow up after differentiated thyroid carcinoma. Patients were separated into 2 groups, those on hormone withdrawal (G I) and rhTSH-stimulated patients on hormone substitution (G II). Results: Iodine excretion was significantly lower in hypothyroid patients (G I, median 50 μg/l, range: 25-600 μg/l) than in those under levothyroxine medication (G II, median 75 μg/l, 25-600 μg/l, p <0.027). TSH in G I (median 57.0 μU/ml, range: 14.4-183 μU/ml) was significantly lower (p <0.001) than in G II (117 μU/ml, 32.2-281 μU/ml). Conclusion: Iodine excretion was higher in patients under rhTSH-stimulation than after hormone withdrawal. This may indicate an increased iodine pool in rhTSH-stimulated patients (deiodination of levothyroxine), thus limiting the sensitivity of radioio-dine scanning to the level of endogenous stimulation despite significantly higher TSH levels during rhTSH-stimulation.

Malignant melanoma and 18F-FDG-PET: Should the whole body scan include the legs?

Aim: 18F-FDG-PET (FDG-PET) is established in staging and follow-up of malignant melanoma. The legs are affected in 10-40% at time of diagnosis even if the primary is at the arms and torso. Imaging including the legs may detect distant manifestations but increases duration of the scan by ~30 min. We intended to disclose the diagnostic benefit of scanning the legs and to evaluate the therapeutic benefit resulting. Patients, Methods: In this retrospective analyse 213 consecutive PET studies of 153 patients with suspected or recent malignant melanoma were re-evaluated for metastastic spread by a blinded investigator. Histopathological follow-up was assessed for confirmation. Results: Suspicious findings at the legs were depicted in 53 patients on 76 occasions. 38/53 showed pathologic uptake in the torso as well. In 15/53 patients it was restricted to the legs. One of them had a hitherto unknown, clinically relevant finding that was not apparent in palpation and inspection. In 6 other patients with primary location at the legs a validation of the positive PET findings was not possible up to now. Conclusion: Metastases and local recurrence of malignant melanoma at the legs were found in 41% of women and 27% of men. However, a long scan does not yield relevant additional data. We found isolated new manifestations at the legs in only 1/153 patients. We recommend performing a long scan only in patients with previous melanoma manifestations restricted to the legs. In all other cases a short scan of the torso and proximal thighs is sufficient. This allows a higher number of PET-scans without loss of diagnostic power and a shorter examination time.

Multicenter Study Differentiated Thyroid Carcinoma (MSDS)

Aim: The Multicenter Study Differentiated Thyroid Carcinoma (MSDS) is an ongoing study in Germany, Austria, and Switzerland on the clinical benefit of adjuvant external beam radiotherapy (RTx) for locally invasive differentiated thyroid carcinoma (DTC) in TNM stages pT4 pN0/1/x M0/x (5th ed. 1997). Methods: MSDS was designed as a prospective randomized trial. Patients receive thyroidectomy, radioiodine therapy (RIT) to ablate the thyroid remnant, and TSH-suppressive L-thyroxine therapy with or without RTx after documented elimination of cervical iodine-131 uptake (http://msdsstudie.uni-muenster.de). Results: 311 patients were enrolled between January 2000 and March 2003. 279 patients met the trial’s inclusion criteria. 45 consented to randomization, of whom 17 were randomized into treatment arm A (RTx) and 18 into arm B (no RTx).

Advised by the trial’s independent Data Monitoring and Safety Committee, the MSDS steering committee decided to terminate randomization in April 2003 and continue MSDS as a prospective cohort study. 23 of the 234 patients in the observation arm of the trial were prescribed RTx by their physicians. Thus, 14% of the trial cohort were randomized or assigned to receive RTx (intention-to-treat analysis). In contrast, at least 44% of all patients with pT4 papillary DTC in Germany in the nationwide PCES study underwent RTx in 1996 (p <0.001, χ2-test). Conclusions: Acceptance of external beam RTx as a treatment modality for DTC has receded to a degree that accrual of a sufficient number of patients for a randomized trial has been impossible. Observation of the trial cohort is continued in order to assess clinical event rates with and without RTx and chronic RTx toxicity.

Myocardial perfusion scintigraphy in Germany

The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine (DGN), in cooperation with the working group Nuclear Cardiology of the German Cardiac Society (DGK), decided to conduct a national survey on myocardial perfusion scintigraphy (MPS). Method: A questionnaire to evaluate MPS for the year 2005 was sent. Results: 346 completed questionnaires had been returned (213 private practices, 99 hospitals and 33 university hospitals). MPS of 112 707 patients were reported with 110 747 stress and 95 878 rest studies. The majority (>75%) was performed with 99mTc-MIBI or tetrofosmin. 201Tl stress-redistribution was used in 22 637 patients (20%). The types of stress were exercise in 78%, vasodilation with adenosine or dipyridamol in 21% and dobutamine in 1%. 99.97% of all MPS were SPECT studies. Gated SPECT was performed in 36% of the stress and in 32% of the rest studies. An attenuation correction was used in 21%. 29 institutions (8%) performed gated SPECT (stress and rest) and attenuation correction. 47% of all MPS were requested by ambulatory care cardiologists, 17% by internists, 12% by primary care physicians, 21% by hospital departments and 2% by others. Conclusion: In Germany, MPS is predominantly performed with 99mTc-perfusion agents. The common type of stress is ergometry. Gated SPECT and attenuation correction do not yet represent standards of MPS practice in Germany, which indicates some potential of optimization.

Overtherapy or undertherapy for papillary thyroid microcarcinoma?

Papillary thyroid microcarcinomas £1 cm have an excellent prognosis both in terms of overall and relapse-free survival. Their high prevalence in autopsy series suggests that most papillary microcarcinomas do not progress to clinically relevant cancer. The extent of surgery is still controversial. Lobectomy or subtotal resection are standard procedures, but multifocal microcarcinomas or lymph node metastases might be overlooked. The pros and cons of completion thyroidectomy and ablative radioiodine therapy are based on limited evidence due to heterogenous inclusion criteria in published series. The retrospective data analyses included subgroups with infiltration of the thyroid capsule, lymph node metastases or multifocal microcarcinomas at the primary staging. The local relapse rate reached approximately 7% after different therapeutic regimes. Radioiodine ablation decreased the recurrence rate in some retrospective studies, but data are inconsistent. Successful radioiodine ablation is possible also after less radical surgery without complete thyroidectomy with postoperative 131I uptake of 10 to 20% or remnants of 3-8 ml. This concept was evaluated successfully in a monocentric series of patients with multifocal microcarcinomas. The therapeutic consideration should include the diameter of the carcinoma, neigh-bourhood to the thyroid capsule, histopathologic subgroups, age, familiar occurrence, patient’s informed consent and in future moleculargenetic tests, too. Therefore, limited surgical procedures for small papillary carcinomas as therapeutic standard, respectively thyroidectomy, lymph node dissection in the central compartment of the neck and ablative radioiodine therapy for individual cases are options for experienced surgeons and specialized tumour centers.

Moyamoya syndrome: Impaired hemodynamics on ECD SPECT after EEG controlled hyperventilation

Background and purpose: Ischemic symptoms in children with Moyamoya syndrome are typically provoked by hyperventilation (HV) and are accompanied by the “re-build-up” phenomenon in EEG. The value of scintigraphic detection of HV-provoked perfusion deficits remains to be elucidated. Patients and methods: In seven children with Moyamoya syndrome regional cerebral blood flow was assessed by 99mTc-ethyl-cysteine-dimer (ECD) single photon emission computed tomography (SPECT) after HV and under baseline conditions to identify ischemia prone regions. Results: Regional marked hypoperfusion after HV was found in all patients. Predominant perfusion deficits were detected in the frontal lobes. Conclusion: ECD SPECT is a potential tool for the preoperative evaluation of cerebral hemodynamics and for monitoring angiosurgical therapies in Moyamoya disease.

FDG-PET in Hodgkin lymphoma

The high negative predictive value of FDG-PET in therapy control of Hodgkin lymphoma is proven by the data acquired up to now. Thus, the analysis of the HD15 trial has shown that consolidation radiotherapy might be omitted in PET negative patients after effective chemotherapy. Further response adapted therapy guided by PET seems to be a promising approach in reducing the toxicity for patients undergoing chemotherapy. The criteria used for the PET interpretation have been standardized by the German study groups for Hodgkin lymphoma patients and will be reevaluated in the current studies.

Myocardial perfusion scintigraphy 2006 in Germany

Aim: This second survey was to deliver further information on myocardial perfusion scintigraphy (MPS) in Germany in 2006. Method: 351 questionnaires were evaluated: 207 private practices (PP), 117 hospitals (HO), 27 from university hospitals (UH). Results: MPS of 106 331 patients were reported, 85% were investigated with 99mTc-perfusion tracers. 74% [2005=72%] were performed in PP, 17% [2005=15%] in HO and 9% [2005=13%] in UH. PP, which participated in 2005 and 2006, demonstrated an increase by 3,9% (HO 0%, UH –13,0%). The type of stress was pharmacological in 27% [2005=22%]; 54% adenosine (of these 29% with exercise), 37% dipyridamole (of these 56% with exercise), and 9% dobutamine. Gated SPECT was performed in 42% [2005=36%] of all restand in 39% [2005=32%] of all stress MPS. An attenuation correction was used by 69 [2005=78] institutions. 40% of all MPS were performed in patients suspected to have CAD. 24% of all institutions reported changes in the use of MPS by competing methods. Conclusion: There is a small increase of MPS between 2005 and 2006 despite competing methods. Gated SPECT has experienced more acceptance. Suspicion of CAD is an important indication of MPS. In order to tap the full potential of MPS a gated SPECT should be performed routinely.

Diagnostic value and therapeutic impact of 18F-FDG-PET/CT in differentiated thyroid cancer

The clinical significance of 18F-FDG-PET/CT in the follow-up of patients with differentiated thyroid carcinoma was evaluated and the results were compared with those of 18F-FDGPET, 131I-whole-body scintigraphy including SPECT/CT (WBS) and ultrasound. In addition, it was the aim to investigate the impact of 18F-FDG-PET/CT on the therapeutic management. Patients, methods: 327 patients (209 women, 118 men; mean age 53 ± 18 years) with differentiated thyroid cancer (242 papillary, 75 follicular, 6 mixed, 1 Hürthle cell and 3 poorly differentiated tumours) were analyzed retrospectively at four tertiary referral centres. 289 18F-FDG-PET/CT and 118 18F-FDG-PET studies were performed in these patients between 2007 and 2010. In addition, an overall clinical evaluation was performed, including cytology, histology, thyroglobulin level, ultrasound, WBS, and subsequent clinical course in order to compare the molecular imaging results. Finally, the change in therapeutic management due to findings of 18F-FDG-PET/CT was investigated. Results: The sensitivity of 18F-FDG-PET/CT was 92%, the specificity was 95%. Sensitivity and specificity of 18F-FDG-PET alone were 67% and 93%, respectively. WBS showed a sensitivity of 65% and a specificity of 94%. The corresponding values of ultrasound were 37% and 94%, respectively. The sensitivity of 18F-FDG-PET/CT in the group of patients with a negative WBS (n=194) amounted to 96%. When 18F-FDG-PET/CT and WBS were considered in combination, tumour tissue was missed in only 2 out of 133 patients; when 18F-FDG-PET and WBS were combined, tumour tissue was missed in 1 out of 24 patients. 18F-FDG-PET/CT resulted in management change in 43% (n=57/133) with a decision on surgical approach in 20% (n=27/133). Conclusions: 18F-FDG-PET/CT is superior to 18F-FDG-PET alone in patients with differentiated thyroid cancer and has a direct impact on the therapeutic management of patients with suspected local recurrence or metastases, particularly in those with negative WBS.

Whole-body imaging of oncologic patients using 16-channel PET-CT

Aim: This study evaluated a MDCT protocol for contrast-enhanced 16-channel PET-CT with regard to scan range and duration of a whole-body 18F-FDG PET-CT examination, the occurrence of contrast-material induced artefacts and quantitative assessment of CT attenuation. Patients, methods: 205 patients (51.9 ± 12.4 years) with different malignant tumours underwent whole-body PET-CT; the study protocol had been approved by the institutional review board. Contrast-enhanced MDCT (16 ˟ 1.5 mm; 120 ml Iomeprol 3 ml/s, 50 ml saline chaser bolus, scan delay 70 s; oral contrast) was also used for attenuation correction. From MDCT data mean scan range and duration, occurrence of contrast media-induced artefacts, and mean CT densities of jugular (jv) and subclavian (scv), superior (vcs) and inferior (vci) caval, portal (pv), and bilateral external iliac veins, pulmonary (ap) and iliac arteries, descending thoracic and abdominal aorta, all cardiac chambers, as well as both liver lobes, spleen, adrenal glands and kidneys were determined. Results: Attenuation corrected PET images were free of contrast media-related image artefacts. Homogeneous contrast enhancement was found in the mediastinal veins (right/left jv 171 ± 34/171 ± 35, scv 127 ± 50/127 ± 40, vcs 153 ± 36 HU) and arteries (e.g. ap 145 ± 26/151 ± 26). Cardiac chambers, abdominal vessels (e.g. vci 138 ± 24, pv 159 ± 25 HU), and parenchymal organs revealed sufficient and homogenous contrast-enhancement in all cases. No beam-hardening artefacts occurred in the neighbourhood of the subclavian veins. Conclusion: The chosen whole-body 18F-FDG 16-slice PET-CT protocol allowed for craniocaudal CT scanning with high vessel and parenchymal contrast revealing no IV contrast-media induced artefacts in attenuation-corrected PET data sets.

Peace of mind for patients with differentiated thyroid cancer?

Differentiated thyroid carcinomas (DTC) have an excellent prognosis, with 10-year overall survival rates over 90%. In addition, DTC patients benefit from their lifelong medical surveillance. The aim of the study was to compare the patients’ overall survival with that of a matched general population. Patients and methods: We have analyzed 1497 consecutive patients with DTC, who underwent radioiodine therapy in Münster, Germany, according to international standards. We classified our patients according to the current 7th edition of the UICC (Union Internationale Contre le Cancer) classification and we compared the overall survival of the patients with the expected survival based on age and sex of the general population as provided by the Federal Statistical Office, Germany. Results: There were no significant differences in overall survival rates between DTC patients of the cohort in stages I to IVa compared to the expected survival based on age and sex of the general population. However, patients in stage IVc showed a significantly worse overall survival rate using the log-rank test (p < 0.0001). Conclusion: Patients with DTC showed excellent overall survival rates in stages I, II, III and IVa. All patients, except for those in stage IVc (M1 ≥ 45 years), had overall survival rates similar to the general population.

Guideline for radioiodine therapy for benign thyroid diseases (version 4)

Version 4 of the guideline for radioiodine therapy for benign thyroid diseases includes an interdisciplinary consensus on decision making for antithyroid drugs, surgical treatment and radioiodine therapy. The quantitative description of a specific goiter volume for radioiodine therapy or operation was cancelled. For patients with nodular goiter with or without autonomy, manifold circumstances are in favor of surgery (suspicion on malignancy, large cystic nodules, mediastinal goiter, severe compression of the trachea) or in favor of radioiodine therapy (treatment of autonomy, age of patient, co-morbidity, history of prior subtotal thyroidectomy, profession like teacher, speaker or singer). For patients with Graves' disease, radioiodine therapy or surgery are recommended in the constellation of high risk of relapse (first-line therapy), persistence of hyperthyroidism or relapse of hyperthyroidism. After counseling, the patient gives informed consent to the preferred therapy. The period after radioiodine therapy of benign disorders until conception of at least four months was adapted to the European recommendation.

Procedure guideline for radioiodine therapy and 131iodine whole-body scintigraphy in paediatric patients with differentiated thyroid cancer

The procedure guideline for radioiodine (131I) therapy and 131I whole-body scintigraphy of differentiated thyroid cancer in paediatric patients is the counterpart to the procedure guidelines (version 3) for adult patients and specify the interdisciplinary guideline for thyroid cancer of the Deutsche Krebsgesellschaft concerning the nuclear medicine part. Characteristics of thyroid cancer in children are the higher aggressiveness of papillary thyroid cancer, the higher frequency of extrathyroidal extension and of disseminated pulmonary metastases as well as the high risk of local recurrences. Radioiodine therapy is generally recommended in children, the 131I activity depends on the children's body weight. Radioiodine ablation in children with small papillary cancer (≤1 cm) should be considered. TSH stimulation is reached two weeks (children) or three weeks (adolescents) after withdrawal of thyroid hormones. Anti-emetic drugs are highly recommended. CT of the chest and examination of pulmonary function are clearly indicated if there is any suspicion on metastases. 3–6 months after 131I ablation, the 131I whole-body scintigraphy is highly recommended as lymph node metastases are frequently detected in paediatric patients. Follow-up care should be arranged in shorter intervals than in adults to test the compliance and to adapt dosage of thyroid hormones to the children's body weight. Reference values of fT3 are higher in children than in adults. Evidence is insufficient to describe in which constellation the TSH may be kept within the low normal level. Therefore, TSH suppression is generally recommended.

Radioiodine remnant ablation in differentiated thyroid cancer after combined endogenous and exogenous TSH stimulation

Aim: Radioiodine remnant ablation (RRA) after (near-)total thyroidectomy (TE) is a key element in patients with differentiated thyroid cancer (DTC). The use of exogenous TSH stimulation (rhTSH) prior to RRA has shown promising results as compared to conventional thyroid hormone withdrawal (THW). As yet, the efficacy of RRA after brief THW and single rhTSH administration has not been assessed. Patients, methods: The study sample comprised 147 patients with DTC referred to our center between May 2008 and September 2010. All patients received TE with subsequent RRA. None of these 147 patients had evidence of distant metastasis. 93 patients had endogenous TSH stimulation 4–5 weeks after surgery (group I) and twenty-six received two rhTSH injections (group II). 28 patients were treated with a single rhTSH injection after a brief THW (group III). RRA-Efficacy was assessed three months after therapy by diagnostic whole-body scan and measurement of the tumour marker thyroglobulin (Tg) under TSH stimulation. Results: Three categories of success were defined for remnant ablation. Based on the definition of successful remnant ablation no visible uptake and a Tg ≤ 2.0 ng/ ml (category 1) was seen in 62/93 patients in group I, in 17/26 patients in group II (p = n.s.) and in 12/28 patients in group III (p < 0.05). Visible radioiodine uptake and a Tg ≤ 2.0 ng/ml (category 2) was seen in 16/28 patients of group III and thus significantly more frequent than in group I (28/93 patients) (p < 0.01). However, patients in group III (16/28 patients) and group II (8/26 patients) showed no significant difference in this category (p = n.s.). Visible radioiodine uptake and a Tg > 2.0 ng/ml (category 3) was found in 3/93 patients in group I and 1/26 patients in group II but in no patient in group III. Conclusion: The third strategy of remnant ablation using a single injection of rhTSH after a brief THW period resulted in a significant higher rate of patients with residual uptake in the thyroid bed and a Tg level below 2 ng/ml three months after remnant ablation in comparison to THW. However, the overall efficacy of the third protocol was not significantly different as compared to two rhTSH injections. Under the aspect of the supply shortage of rhTSH the combined endogenous and exogenous TSH stimulation may be an attractive alternative for remnant ablation in differentiated thyroid cancer.

Procedure guideline for iodine-131 whole-body scintigraphy for differentiated thyroid cancer (version 3)

Version 3 of the procedure guideline for 131I whole-body scintigraphy (WBS) is the counterpart to the procedure guideline for radioiodine therapy (version 3) and specify the interdisciplinary guideline for thyroid cancer of the Deutsche Krebsgesellschaft concerning the nuclear medicine part. 131I WBS 3–6 months after 131I ablation remains a standard procedure in an endemic area for thyroid nodules and the high frequency of subtotal surgical procedures. Follow-up without 131I WBS is only justified if the following preconditions are fulfilled: low-risk group pT1–2, pN0 M0 with histopathologically confirmed pN0, 131I uptake <2%, 131I WBS during ablation without any suspicious lesion, stimulated thyroglobulin (Tg)-level 3–6 months after ablation <2 ng/mL, and absence of anti-thyroglobulin- antibodies with normal recovery-testing. If patients from the low-risk group show normal 131I WBS 3–6 months after ablation and stimulated Tg is of <2 ng/mL, there will be no need for additional routine 131I WBS. If patients from the high-risk group show normal 131I WBS and stimulated Tg-level of <2 ng/mL 3–6 months after ablation, the follow- up care should include repeated stimulated Tgmeasurements. If the Tg-level remains below 2 ng/mL, an additional 131I WBS will be not necessary. The recommended intervals for stimulated Tg-testing are adapted to the prior intervals for 131I WBS-testing in the high-risk group. Increased anti-thyroglobulin-antibodies or incomplete recovery-testing make an individual strategy of follow- up care necessary, which include 131I WBS.

Procedure guidelines for radioiodine therapy of differentiated thyroid cancer (version 3)

The procedure guideline for radioiodine therapy (RIT) of differentiated thyroid cancer (version 3) is the counterpart to the procedure guideline for 131I whole-body scintigraphy (version 3) and specify the interdisciplinary guideline for thyroid cancer of the Deutsche Krebsgesellschaft concerning the nuclear medicine part. Recommendation for ablative 131I therapy is given for all differentiated thyroid carcinoma (DTC) >1 cm. Regarding DTC ≤1 cm 131I ablation may be helpful in an individual constellation. Preparation for 131I ablation requires low iodine diet for two weeks and TSHstimulation by withdrawal of thyroid hormone medication or by use of recombinant human TSH (rhTSH). The advantages of rhTSH (no symptoms of hypothyroidism, lower blood activity) and the advantages of endogenous TSHstimulation (necessary for 131I-therapy in patients with metastases, higher sensitivity of 131I whole-body scan) are discussed. In most centers standard activities are used for 131I ablation. If pretherapeutic dosimetry is planned, the diagnostic administration of 131I should not exceed 1–10 MBq, alternative tracers are 123I or 124I. The recommendations for contraception and family planning are harmonized with the recommendation of ATA and ETA. Regarding the best possible protection of salivary glands the evidence is insufficient to recommend a specific setting. To minimize the risk of dental caries due to xerostomia patients should use preventive strategies for dental hygiene.