Background . Lenvatinib has proven efficacy in progressive, radioiodine- (RAI-) refractory thyroid cancer (TC). Dose reductions are commonly performed due to decreased tolerability and adverse effects. This retrospective multicenter study analyzed overall survival (OS) and progression-free survival (PFS) and tolerability in the Austrian patient population treated with lenvatinib. Methods . Clinical data of 43 patients (25 males and 18 females) with a median age of 70 years (range: 39–91 years) and RAI-refractory TC with metastases to the lymph nodes (74%), lungs (86%), bone (35%), liver (16%), and brain (12%) were analyzed. The mean duration of treatment with lenvatinib was 26.6 ± 15.4 months with dosage reductions required in 39 patients (91%). Results . PFS after 24 months was 71% (95% CI: 56–87), and overall survival (OS) was 74% (95% CI: 60–88), respectively. OS was significantly shorter ( p = 0.048) in patients with a daily maintenance dosage ≤ 10 mg (63%) (95% CI: 39–86) as compared to patients on ≥ 14 mg lenvatinib (82%) (95% CI: 66–98) daily. Dose reduction was noted in 39 patients (91%). Grade ≥3 toxicities (hypertension, diarrhea, weight loss, and palmar-plantar erythrodysesthesia syndrome) were most common leading to discontinuation of lenvatinib in 7 patients (16%). Conclusion . Lenvatinib showed sustained clinical efficacy in patients with metastatic RAI-refractory TC even with reduced maintenance dosages over years. The effects were comparable to the registration trial, although patients had a higher median age and, more commonly, dose reductions.

Aim: To demonstrate the clinical capability of ultra-fast whole body PET acquisition enabled by digital photon counting PET (dPET) and to assess and compare its diagnostic and quantitative characteristics to current clinical PET acquisition.Methods: Twenty-five patients scheduled for FDG whole body PET/ CT were imaged using three separate acquisitions as part of intraindividual comparison study with a pre-commercial release dPET/CT (Vereos) and cPET/CT (Gemini, Philips, Cleveland).Standard cPET imaging was performed at ~75 min p.i. of ~450 MBq FDG with investigational dPET imaged at ~55 min p.i.The first dPET acquisition was performed using 90s/bed position, immediately followed by a 9s/bed position.Acquisition which lead to average table times of ~15 and ~2 min.These were compared with standard-of-care 90s/bed position cPET.The 9s/bed dPET listmode data were reconstructed using a previously optimized methodology.All other aspects of image acquisition were kept identical.Three blinded reviewers evaluated the data sets regarding visual characteristics, diagnostic confidence and semiquantitative readouts.Results: Visual assessment scores were significantly higher for 90s/bed dPET whole body (p<0.01) with no difference between 9s/bed dPET and 90s/bed cPET.Quantitatively, the 9s/bed dPET images presented slightly increased background noise, however there was no significant impact on diagnostic confidence or SUV measures of FDG-avid lesions.Conclusion: Next generation digital photon counting PET detector technology enables a new capability of Ultra-Fast (~2min) wholebody acquisition with comparable diagnostic confidence and quantitative precision to current generation cPET acquisitions taking 10 times longer.This allows for new PET workflow concepts, improved patient comfort, minimized patient motion and whole-body pseudo-dynamic imaging of tracer uptake.

There is no clear standard therapy for patients with radioactive iodine (131I)-refractory locally advanced or metastatic differentiated thyroid cancer. The therapeutic options for this indication have expanded with the recently approved multiple kinase inhibitor sorafenib. Recommendations for the definition and the management of iodine refractory patients were worked up by an interdisciplinary expert panel, consisting of endocrine surgeons, medical oncologists and nuclear medicine specialists.

CAD Imaging: Role of Myocardial Perfusion Scintigraphy in the Context of Alternative Non-Invasive and Invasive Methods. The Myocardial Perfusion Scintigraphy (MPS) is one of the most validated non-invasive diagnostic procedures in the diagnostics of Coronary Artery Disease (CAD) and deep-seated in the European and American guidelines. There is a broad consensus concerning the value of the

The Myocardial Perfusion Scintigraphy (MPS) is one of the most validated non-invasive diagnostic procedures in the diagnostics of Coronary Artery Disease (CAD) and deep-seated in the European and American guidelines. There is a broad consensus concerning the value of the MPS as a non-invasive diagnostic intrument in patients with an intermediate probability of CAD. Several metaanalyses demonstrated a mean sensitivity of 87% and a specificity of 73% in the detection of a significant CAD, demonstrated by coronary angiography, independend of the examined population. Due to several technical advances in the last years (ECG-Gating, Attenuation- and Scatter Correction), a further increase in diagnostic accuracy to more than 90 % is possible. Additionally, MPS delivers important prognostic information. The annual rate of severe cardiac events in the case of a negative MPS is below 1%.

Differentiated Thyroid Carcinoma: Basic Aspects of Diagnosis, Therapy, and Follow-up from a Nuclear-Medicine Perspective. Differentiated thyroid carcinoma is the most common neoplasm of the endocrine glands. Both papillary and follicular thyroid carcinoma have a favourable prognosis. The challenge in the diagnostic work-up of nodular goitre is to discriminate the few malignant from the majority of benign nodules. Even though the specificity of ultrasound criteria for malignancy is high, the sensitivity is proven to be quite low. Thus, further scintigraphic techniques and ultrasound-guided fineneedle aspiration biopsy are well-established in clinical routine. In contrast to anaplastic and medullary thyroid carcinoma, radioiodine remnant ablation is a standard procedure subsequent to surgery for patients with differentiated thyroid carcinoma > 1 cm. Only few advanced differentiated thyroid carcinomas may lose the ability to accumulate 131I, thus, radioiodine ablation may be ineffective in these cases. For this group of tumours with a worse prognosis, miscellaneous therapeutic strategies are undergoing clinical testing. J Klin Endokrinol Stoffw 2012; 5 (1): 11–8.

Differentiated thyroid carcinoma is the most common neoplasm of the endocrine glands. Both papillary and follicular thyroid carcinoma have a favourable prognosis. The challenge in the diagnostic work-up of nodular goitre is to discriminate the few malignant from the majority of benign nodules. Even though the specificity of ultrasound criteria for malignancy is high, the sensitivity is proven to be quite low. Thus, further scintigraphic techniques and ultrasound-guided fineneedle aspiration biopsy are well-established in clinical routine. In contrast to anaplastic and medullary thyroid carcinoma, radioiodine remnant ablation is a standard procedure subsequent to surgery for patients with differentiated thyroid carcinoma > 1 cm. Only few advanced differentiated thyroid carcinomas may lose the ability to accumulate I-131, thus, radioiodine ablation may be ineffective in these cases. For this group of tumours with a worse prognosis, miscellaneous therapeutic strategies are undergoing clinical testing.

Medullary thyroid carcinoma (MTC) originates from the parafollicular cells of the thyroid gland (C-cells) and accounts for approximately 5 % of all thyroid malignancies. MTC occurs either in sporadic (75 %) or hereditary (FMTC, MEN Type 2A, MEN Type 2B) (25 %) forms. Genetic testing facilitates identification of familiar RET (,Rearranged during transfection") proto-oncogen mutation carriers who can subsequently be offered timely prophylactic thyroidectomy with an increased prospect of cure. In addition to clinical findings, biochemical markers, ultrasonography, scintigraphy and ultrasound-guided fine-needle aspiration punction, functional nuclear medicine methods may contribute valuable additional information to a comprehensive diagnostic work-up with particular impact on early recurrence diagnosis and reliable ascertainment of metastatic disease.

PURPOSE:The purpose of this prospective study was to determine the diagnostic impact and influence on patient treatment of posttherapeutic (131)I SPECT-CT when the findings on planar posttherapeutic whole-body scintigraphy (ptWBS) were inconclusive.MATERIALS AND METHODS:A total of 53 SPECT-CT scans were performed in 41 patients with thyroid cancer after high-dose (131)I therapy (2.944 to 7.526 GBq (131)I) because of diagnostic uncertainty on ptWBS. Physiological uptake in the salivary glands, gastric mucosa, gut, nasal mucosa, urinary tract and liver were considered to be normal. Any other foci of increased (131)I uptake, except iodine uptake clearly located in the thyroid bed, were considered to be abnormal. The data were evaluated on a lesion and a patient basis.RESULTS:Regarding neck lesions, SPECT-CT provided a diagnostic impact in 26/90 lesions (28.9%) and confirmed the diagnosis in 64/90 lesions (71.1%). On a patient basis, SPECT-CT changed N status in 12/33 patients (36.4%), provided a diagnostic impact in 21/33 patients (63.6%) and led to a treatment change in 8/33 patients (24.2%). Regarding lesions distant from the neck, SPECT-CT confirmed the diagnosis in 62/71 lesions (87.3%) and had a diagnostic impact in 9/71 lesions (12.7%). On a patient basis, SPECT-CT changed M status in 4/19 patients (21.1%), had a diagnostic impact in 14/19 patients (73.7%) and led to a treatment change in 2/19 patients (10.5%). Considering all patients, SPECT-CT led to a treatment change in 10/41 patients (24.4%).CONCLUSION:Integrated SPECT-CT is a useful tool, especially in cases of diagnostic uncertainty and helps to individualize patient management.

The aim was to compare two thyroglobulin-immunoradiometric assays (Tg-IRMA) in the follow-up of patients with differentiated thyroid carcinoma (DTC) in order to set up interassay correlation, correlation to clinical background, and to determine whether a lower functional sensitivity (kit A: 0.5 ng/mL, kit B: 0.3 ng/mL) would allow an earlier detection of recurrences. Three hundred eight samples from 181 patients with DTC were investigated. The clinical interpretation of the Tg-IRMA results was based on comprehensive imaging and the clinical history before and during the study period. Groups were formed against this background and against the thyrotropin (TSH) levels of the samples (LT4- on and LT4-off). During a follow-up period that lasted until September 1998, the clinical situation was reevaluated in order to determine any changes in the patients' clinical status. The two assays presented a good interassay correlation of 0.838. Both assays had a high and comparably good sensitivity in the detection of recurrence of malignancy or distant metastases. Patients in remission had, in most cases, nonmeasurable or Tg values below 1 ng/mL. Kit B presented slightly measurable Tg results in a larger number of patients in remission; however, during the follow-up most of these slightly measurable Tg results were not reproducible, thus being most likely artifacts. Consequently, the functional sensitivity of 0.3 ng/mL of kit B showed no advantages in terms of an earlier tumor detection and seems to be unacceptably low. Negative consequences may be an increase in the number of investigations during the follow-up, which may be disconcerting for both the clinicians and the patients.

SummaryF‐18 fluorocholine [fluoromethyl‐dimethyl‐2‐hydroxyethyl‐ammonium (FCH)] is a choline analogue that shows great structural similarity to natural choline. The pathophysiological basis for the use of choline and its derivates for prostate cancer (PC) imaging are the elevation of choline levels and the up‐regulation of choline kinase activity in malignant cells. In order to allow rapid tumour growth, malignant cells are able to trap choline to produce phosphatidylcholine, part of the cellular membrane. As shown in recent studies, F‐18 choline PET and PET/CT might be a valuable tool in detecting the primary tumour in case of elevated prostate‐specific antigen (PSA) serum levels. However, data are not consistent, and further research is necessary before general recommendations concerning F‐18 choline PET and PET/CT can be given in this setting. Furthermore, some studies investigated the accuracy of F‐18 choline PET and PET/CT in detecting lymph node or bone metastases and local recurrences in case of PSA relapse in patients with a history of PC.

PURPOSE:Patients with persistent elevated PSA and repeated negative prostate biopsy, that means having the prostate biopsied at multiple times, were investigated with 18F-choline PET/CT to delineate prostate cancer and guide renewed prostate biopsy.METHODS:Twenty patients with elevated PSA and negative prostate biopsies underwent 18F-choline PET/CT. We performed an early examination of the pelvic region 3-5 min after application. After 30 minutes a whole body PET/CT examination was performed. Image analysis was performed visually and by semi-quantitative analysis calculating the maximum standardised uptake value (SUVmax). 18F-choline uptake was defined as focal, multifocal or inhomogeneous. After the 18F-choline PET/CT, all patients underwent a repeated prostate biopsy, and in the cases where a focal or multifocal uptake was found, the biopsy was guided by the result of the examination.RESULTS:Qualitative image analysis revealed focal 18F-choline uptake in 13 out of 20 patients. In five patients, prostate cancer was revealed by repeated aspiration biopsy. None of the patients with a multifocal or inhomogeneous 18F-choline uptake had a malignant neoplasm in the prostate. Semiquantitative analysis performed with SUVmax was not helpful in the discrimination of malignancy but showed high values also in benign prostate diseases, as well as in normal prostate tissue. The dual-phase protocol delivered no clear benefit in discriminating malignancy from benign alterations.CONCLUSION:The use of 18F-choline cannot be generally recommended for localising prostate cancer; however, in highly selected patients, we found useful additional information. In 25% of patients, 18F-choline PET/CT allowed the identification of neoplastic prostatic zones.

SummaryF‐18 FDG positron emission tomography (PET) is able to diagnose viable lymphoma tissue due to its elevated glucose metabolism, independent of the size of the lesions. For staging purposes, the value of FDG PET in Hodgkin’s (HL) and high‐grade non‐Hodgkin lymphoma (NHL) lies predominantly in a change of tumour stage with the consequence of a modification of therapeutic regimen and a more exact definition of radiotherapy (RTX) planning volume. In indolent lymphoma, a pre‐therapeutic scan is mandatory for further therapy monitoring due to variable FDG‐uptake. In restaging HL and NHL, discrimination between viable residual lymphoma and necrosis in case of a residual bulk is possible with FDG PET, which is limited by conventional methods. PET/CT combines the advantages of PET and CT and performs better than each method alone by further improving the accuracy of staging and response assessment over that of CT alone. There are a lower proportion of equivocal or benign findings because PET‐CT specifies the nature of uptake. Some studies have demonstrated the possibility of therapy monitoring, but further prospective studies have to be performed before therapy may be avoided or modified according to the results of the PET/CT examination.