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ZusammenfassungUltraschall ist die bildgebende Basisdiagnostik zur Beurteilung der Schilddrüse. Aufgrund der hohen Prävalenz struktureller Parenchymveränderungen kommt das Untersuchungsverfahren in Deutschland sehr häufig zum Einsatz, in vielen Fällen im Rahmen von Verlaufskontrollen. Die Beurteilung thyreoidaler Pathologien und deren Dynamik unterliegt einer relevanten Inter- und Intraobservervariabilität. Befunde die während des Live-Ultraschalls nicht identifiziert und aufgezeichnet wurden, können retrospektiv nicht mehr beurteilt werden. Durch die Akquisition und Dokumentation von standardisierten Videosequenzen der Ultraschallbilder (sogenannte Cine Loops), wird eine sekundäre Nachbetrachtung unter Berücksichtigung von Voraufnahmen analog anderer Schnittbildverfahren wie der CT oder MRT möglich. Die Durchführung könnte dabei auch von nichtärztlichem Personal übernommen werden. Das gewonnene Bildmaterial kann im lokalen PACS gespeichert und für die Lehre und Forschung verwendet werden.

ZusammenfassungDie nuklearmedizinische Ultraschall-Fusionsbildgebung lässt sich unter anderem für die Diagnostik der Schilddrüse und Nebenschilddrüsen klinisch sinnvoll einsetzen und erlaubt die zweifelsfreie räumliche Korrelation metabolischer und morphologischer Informationen. Allerdings beschränkt sich die praktische Anwendung aufgrund derzeit noch limitierender Aspekte auf ausgewählte Fälle und wissenschaftliche Untersuchungen. Die Entwicklung eines integrierten hybriden Detektors zur simultanen nuklearmedizinisch-sonografischen Bildgebung wäre eine Möglichkeit, die bestehenden Limitationen zu überwinden.

ZusammenfassungAufgrund der hohen Inzidenz von Schilddrüsenerkrankungen besitzt die Ultraschalluntersuchung des Halses in vielen nuklearmedizinischen Abteilungen einen hohen Stellenwert. Ein präzises Sonogramm mit hoher Ortsauflösung und Bildschärfe über den gesamten Abbildungsbereich bei gleichzeitig minimaler Artefaktbelastung, ist die Voraussetzung, um dem Anspruch hoher diagnostischer Genauigkeit in der modernen Medizin gerecht zu werden. In den letzten 20–30 Jahren konnte eine Vielzahl wegweisender technischer Innovationen, wie die Entwicklung des Matrix-Arrays, die elektronische Bildfokussierung, die multidirektionale Abstrahlung, die Artefaktlimitation durch Speckle-Reduktion und Harmonic Imaging sowie die Möglichkeit der Sichtfelderweiterung, umgesetzt werden.

ZusammenfassungDer obere Grenzwert für das Schilddrüsenvolumen beträgt bei Frauen 18 ml und bei Männern 25 ml. Diese Referenzgrößen werden fachgebietsübergreifend in vielen Kliniken und Praxen verwendet und gelehrt. Insofern sind sie auch Grundlage therapeutischer Entscheidungen. Doch wo kommen die Normalwerte für das Schilddrüsenvolumen her und auf Basis welcher Untersuchungen wurden sie etabliert? Sollten diese Obergrenzen in der klinischen Routine als universeller Maßstab angewendet werden und welche Faktoren können die physiologische Organgröße beeinflussen? Der folgende Artikel widmet sich einer kritischen Betrachtung der weitverbreiteten Referenzwerte für das Volumen der Schilddrüse in der erwachsenen Bevölkerung.

Holmium-166 microspheres are used for the transarterial radioembolization (TARE) treatment of primary and secondary liver cancers. In this study, its efficacy regarding local tumor control and integration into the oncological treatment sequence of the first 20 patients treated in our institution were examined. A total of twenty-nine 166Ho-TARE procedures were performed to treat hepatocellular carcinoma (HCC, fourteen patients), metastatic colorectal cancer (mCRC, four patients), intrahepatic cholangiocarcinoma (ICC, one patient), and hemangioendothelioma of the liver (HE, one patient). In eight patients, 166Ho-TARE was the initial oncologic treatment. In patients with HCC, the median treated-liver progression-free survival (PFS), overall PFS, and overall survival after 166Ho-TARE were 10.3, 7.3, and 22.1 months; in patients with mCRC, these were 2.6, 2.9, and 20.6 months, respectively. Survival after 166Ho-TARE in the patients with ICC and HE were 5.2 and 0.8 months, respectively. Two patients with HCC were bridged to liver transplantation, and one patient with mCRC was downstaged to curative surgery. In patients with HCC, a median treatment-free interval of 7.3 months was achieved. In line with previous publications, 166Ho-TARE was a feasible treatment option in patients with liver tumors, with favorable clinical outcomes in the majority of cases. It was able to achieve treatment-free intervals, served as bridging-to-transplant, and did not prevent subsequent therapies.

An 83-year-old woman presented with new-onset hyperthyroidism and suspicious thyroid nodules on ultrasound (US). Conventional 99mTcO4 thyroid scintigraphy showed hyperfunctioning areas that could not be clearly assigned to the US findings. With the aid of 123I-SPECT/US fusion imaging, suspicious nodules were unambiguously identified as autonomously hyperfunctioning lesions. Additional 123I whole-body scan revealed iodine-avid lymphonodular and pulmonal metastases. Clinical diagnosis of hormone-active thyroid carcinoma was made and histologically confirmed. Because of significant hyperthyroidism as well as multiple partially iodine-negative metastases, a multimodal treatment regime consisting of 131I radioiodine therapy, surgery, and radiation therapy was conducted, leading to almost complete remission.

Background: Prostate-specific membrane antigen (PSMA)-directed radioligand therapy (RLT) is a novel treatment for patients with castration-resistant prostate cancer (CRPC). Given the mode of action, patients in an earlier disease stage, such as hormone-sensitive prostate cancer (HSPC), are also likely to benefit from [177Lu]Lu-PSMA- (177Lu-PSMA) or [225Ac]Ac-PSMA-radioligand treatment (225Ac-PSMA). In this retrospective study, we analyzed the safety and efficacy of PSMA-RLT in early-stage and hormone-sensitive metastatic prostate cancer patients. Methods: A retrospective study was performed in patients who received 177Lu-PSMA and/or 225Ac-PSMA with early-stage metastatic prostate cancer. The primary outcome parameter evaluated in this study was the progression-free survival (PFS) after PSMA-RLT and toxicity according to the Common Terminology Criteria for Adverse Events. Secondary outcome parameters were prostate-specific antigen (PSA) response and the date of onset of CRPC state. Results: In total, 20 patients were included of which 18 patients received 177Lu-PSMA radioligand and two patients received tandem treatment with both 177Lu-PSMA and 225Ac-PSMA radioligands. Patients received a median of 2 treatment cycles (range 1–6) and a median activity of 6.2 GBq 177Lu-PSMA per cycle (interquartile range (IQR) 5.2–7.4 GBq). PSMA-RLT was overall well-tolerated. The most common grade 1–2 side effects were xerostomia (n = 6) and fatigue (n = 8), which were only temporarily reported. One patient that received 225Ac-PSMA developed grade 3–4 bone marrow toxicity. The median PFS was 12 months (95% confidence interval (CI), 4.09–19.9 months). Seventeen (85%) patients had a ≥50% PSA response following PSMA-RLT. One patient developed CRPC 9 months following PSMA-RLT. Conclusions: In this small cohort study, PSMA-RLT appeared safe and showed encouraging efficacy for (metastasized) early-stage and hormone-sensitive prostate cancer patients. Prospective studies are awaited and should include long-term follow-up.

After transarterial radioembolization (TARE) with microspheres loaded with holmium-166, radioactivity is excreted from the body. The aim of this study was to evaluate radioactive renal and intestinal excretions after TARE planning and treatment procedures with holmium-166-loaded microspheres and to correlate the findings with the intratherapeutic effective half-life. Urinary and intestinal excretions of patients who underwent TARE procedures were collected during postinterventional intervals of 24 h (TARE planning) and 48 h (TARE treatment). Whole-body effective half-life measurements were performed. Calibrations of the

A 66-year-old woman was referred with an incidental finding of a bilateral papillary thyroid microcarcinoma after thyroidectomy. On the right side, a Warthin-like variant was observed. After radioiodine therapy, whole-body scan revealed an unclear iodine uptake on the right-sided neck. For further clarification, 131I-SPECT/US and 18F-PET/US fusion imaging were performed, unambiguously revealing iodine and glucose uptake within a hypoechoic lesion located in the parenchyma of the right parotid gland. Surgical excision confirmed a Warthin tumor ipsilateral to the Warthin-like variant of the papillary thyroid microcarcinoma. Because the extensive imaging, targeted minimal-invasive surgery was possible.

Systemic pan-tumor analyses may reveal the significance of common features implicated in cancer immunogenicity and patient survival. Here, we provide a comprehensive multi-omics data set for 32 patients across 25 tumor types by combining proteogenomics with phenotypic and functional analyses. By using an optimized computational approach, we discovered a large number of novel tumor-specific and tumor-associated antigens including shared common target candidates. To create a pipeline for the identification of neoantigens in our cohort, we combined deep DNA and RNA sequencing with MS- based immunopeptidomics of tumor specimens, followed by the assessment of their immunogenicity. In fact, we could detect a broad variety of non-wild type HLA-binding peptides in the majority of patients and confirmed the immunogenicity of 24 neoantigens. Most interestingly, the majority of total and immunogenic neoantigens originated from variants identified in the RNA dataset, illustrating the importance of RNA as a still understudied source of cancer antigens. Moreover, the amount of these mainly RNA-based immunogenic neoantigens correlated positively with overall CD8+ tumor-infiltrating T cells. This study therefore underlines the importance of RNA-centered variant detection for the identification of shared biomarkers and potentially relevant neoantigen candidates.Statement of significanceThe significance of this study lies not only in the potential of our optimized proteogenomic workflow for the discovery of neoantigens (in particular RNA-derived neoantigens) for clinical application, but sheds light on the entity-agnostic prevalence of HLA class I peptide presentation of RNA processing events to be used for tumor targeting.

An 80-year-old woman with osteoporosis without fractures was referred with asymptomatic primary hyperparathyroidism and elevated calcitonin level. Ultrasound, 99m Tc-pertechnetate scintigraphy, 99m Tc-MIBI scintigraphy, and CT revealed a suspicious thyroid nodule and enlarged submandibular lymph nodes. However, no parathyroid adenoma was depictable. 18 F-choline PET/CT showed increased uptake of the proximal esophagus, but neither CT nor US revealed a parathyroid lesion, and only 18 F-choline PET/US fusion imaging confirmed a paraesophageal parathyroid adenoma. Resection of both medullary thyroid carcinoma and ectopic parathyroid adenoma through a single cervicotomy was conducted (thyroidectomy, neck dissection, extirpation of parathyroid adenoma); parathyroid hormone and calcitonin dropped to normal. Multiple endocrine neoplasia IIa syndrome was suspected.

Next to the known nosocomial infections, the COVID-19 pandemic was an example for the need for the immediate implementation of functioning hygiene concepts and knowledge transfer. The aim of this study was to evaluate the self-assessment of ehealth literacy in terms of finding, using and critically evaluating health information and theoretical and practical hygiene awareness on a voluntary participation basis at the Jena University Hospital in 2022. The well-established and validated eHEALS and WHO questionnaire on hand hygiene (HH) knowledge for healthcare workers was completely filled by 204 participants (191 medical students; 13 healthcare trainees). In a second step, after the questionnaire, 77 participants completed additional asynchronous, digitally guided self-training using DesiCoach 2Go. In the end, a synchronous hand disinfection was carried out in the hospital using Visirub, by separating it into a group without (n = 191; with and without HH questionnaire) and a group with (n = 31; with HH questionnaire) previously completed self-training. For the eHL, the respondents tended to have a positive self-assessment of finding, using and critically evaluating health information. The voluntary participants of the practical hand disinfection who had received self-training were able to achieve significantly better results (p = 0.0047), resulting in fewer wetting gaps in a subsequent performance with Visirub than those who had not received digital self-training. The survey showed that healthcare-related participants belonging to the “digital native” generation have above-average knowledge on HH and profit by digitally guided self-training.

Purpose: To evaluate the microsphere outflow dynamics and residual Ho-166 activity during and after transarterial radioembolization planning and treatment procedures, and to assess the distribution and predilection sites of residual activity in the proprietary delivery set and the microcatheter. Materials and Methods: Fifteen planning and 12 therapeutic radioembolization procedures were performed with poly-l-lactic acid microspheres loaded with Ho-166. The amount and distribution of residual activity was assessed by dose calibrator measurements and SPECT imaging. The activity flow profile from the microcatheter was assessed dynamically. For planning procedures, different injection methods were evaluated in order to attempt to decrease the residual activity. Results: The median residual activities for planning and treatment procedures using standard injection methods were 31.2% (range 17.3%–44.1%) and 4.3% (range 3.5%–6.9%), respectively. Planning residual activities could be decreased significantly with 2 injection methods similar to treatment procedures, to 17.5% and 10.9%, respectively ( P = 0.002). Main predilection sites of residual microspheres were the 3-way stopcock and the outflow needle connector. During treatment procedures, more than 80% of the injected activity is transferred during the first 3 injection cycles. Conclusion: After treatment procedures with holmium-loaded microspheres, mean residual activity in the delivery set is reproducibly low and between reported values for glass and resin microspheres. The majority of microspheres is transferred to the patient during the second and third injection cycle. An estimated residual waste of 3% to 4% may be included in the treatment activity calculation. For planning procedures, a modified injection technique should be used to avoid high residual activities.

ZusammenfassungAus fachfremder Sicht wird der Stellenwert der „konventionellen“ Schilddrüsenszintigrafie zur Klärung diverser thyreologischer Fragestellungen international mittlerweile weit niedriger eingeschätzt, als dies dem hierzulande tätigen Nuklearmediziner bewusst ist. Dieser Aufsatz gibt einen Überblick über häufig geäußerte Kritikpunkte an der Schilddrüsenszintigrafie und möchte einiges hierzu klarstellen sowie in berechtigten Fällen fundierte Gegenargumente liefern. In diesem Rahmen wird ein Überblick über die weiterhin bestehenden Indikationen gegeben, es werden aber auch Aspekte angeschnitten, bei denen Verbesserungsbedarf besteht. Abschließend erfolgt eine Aussicht auf zukünftige Perspektiven und Weiterentwicklungen der funktionellen Charakterisierung von thyreoidalem Gewebe.

Purpose To evaluate the microsphere flow dynamics and residual yttrium-90 (90Y) activity during and after transarterial radioembolization with glass microspheres and to assess the distribution and predilection sites of residual activity in the administration devices. Materials and Methods In this laboratory investigation, after 18 consecutive clinical transarterial radioembolization and 4 ex vivo experimental procedures with 90Y glass microspheres, the distribution of residual activity in the administration devices was assessed by activimeter and positron emission tomography (PET)/CT measurements. During ex vivo procedures, microsphere outflow from the administration device was assessed by dynamic scintigraphic measurements. Results Mean residual activity was 3.4% ± 1.7 (range, 0.9%–8.8%). Calculations showed a negative correlation between relative residual activity and prescribed activity (r = −0.4258, P = .0486) and a positive correlation between absolute residual activity and prescribed activity (r = 0.5345, P = .0104). The main predilection site was the Luer-Lok microcatheter connector. Lower activities were detected in the dose vial. Flow measurements showed that more than 98% of the final injected activity was transferred to the patient with the first 20 mL of saline solution. Conclusions Residual activity in the standard administration device for glass microsphere radioembolization is considered to be low compared with similar procedures, but is variable. The microsphere flow profile shows an initial peak, resulting in a rapid activity transfer at the beginning of the injection process. The findings may have implications for safe handling of the administration device and for dose calculation of 90Y glass microspheres.

OBJECTIVE. The aim of this study was to evaluate the amount of free radioactivity in renal and intestinal excretions during the first 48 hours after transarterial radioembolization (TARE) procedure...

Purpose: (i) To examine the criterion taller-than-wide (TTW) for the sonographic assessment of thyroid nodules in areas of iodine deficiency in terms of frequency, anatomical distribution within the thyroid gland and risk of malignancy. (ii) To develop a model for nodule growth in the thyroid gland. Methods: German multicenter study consisting of two parts. In the prospective part, thyroid nodules were sonographically measured in all three dimensions, location within the thyroid gland and contact to a protrusion-like formation (horn) in the dorsal position of thyroid gland was noted. In addition, further sonographic features such as the composition, echogenity, margins and calcifications were investigated. All nodules from the prospective part were assessed for malignancy as part of clinical routine at the decision of the treating physician adhering to institutionally based algorithms. In the retrospective part, only nodules with fine needle aspiration and/or histology were included. The risk of malignancy in TTW nodules was determined by correlating them with cyotological and histological results. Results: Prospective part: out of 441 consecutively evaluated thyroid nodules, 6 were found to be malignant (1.4%, 95% CI 0.6–2.7%). Among the 74 TTW nodules (17%), 1 was malignant (1%, 95% CI 0–4%). TTW nodules were more often located in the dorsal half of the thyroid than non-TTW nodules (factor 2.3, p = 0.01, 95% CI 2.1–2.5) and more often located in close proximity to a horn than non-TTW nodules (factor 3.0, p = 0.01, 95% CI 2.4–3.8). Retrospective part: out of 1315 histologically and/or cytologically confirmed thyroid nodules, 163 TTW nodules were retrieved and retrospectively analyzed. A TTW nodule was 1.7 times more often benign when it was dorsal (95% CI 1.1–2.5) and 2.5 times more often benign when it was associated with a horn (95% CI 1.2–5.3). The overall probability of malignancy for TTW nodules was 38% (95% CI 30–46%) in this highly preselected patient group. Conclusion: TTW nodules are common in iodine deficient areas. They are often located in the dorsal half of the thyroid gland and are frequently associated with a dorsal protrusion-like formation (horn) of the thyroid. Obviously, the shape of benign nodules follows distinct anatomical preconditions within the thyroid gland. The frequency of TTW nodules and their predominant benignity can be explained by a pole concept of goiter growth. The difference between the low malignancy risk of TTW nodules found on a prospective basis and the high risk found retrospectively may be the result of a positive preselection in the latter.

The biochemical relapse of prostate cancer is diagnostically challenging but of high clinical impact for subsequent patient treatment. PET/CT with radiolabeled PSMA ligands outperforms conventional diagnostic methods in the detection of tumor recurrence. Several radiopharmaceuticals were and are available for use. The aim of this study was to investigate whether the routinely applied [68Ga]Ga-PSMA ligands PSMA-617, -I&T and -11 (HBED-CC) differ in physiological and pathological distribution, or in tumor detection rate. A retrospective evaluation of 190 patients (39 patients received PSMA-617, 68 patients PSMA-I&T and 83 patients PSMA-11) showed significant differences in tracer accumulation within all organs examined. The low retention within the compartments blood pool, bone and muscle tissue is a theoretical advantage of PSMA-11. Evaluation of tumor lesion uptake and detection rate did not reveal superiority of one of the three radiopharmaceuticals, neither in the whole population, nor in particularly challenging subgroups like patients with very low PSA levels. We conclude that all three [68Ga]Ga-PSMA ligands are equally feasible in this clinically important scenario, and may replace each other in case of unavailability or production restrictions.

A 68-year-old woman was referred with the diagnosis of symptomatic pHPT (primary hyperparathyroidism). Ultrasonography (US) and 99mTc-MIBI scintigraphy could not clearly identify a parathyroid adenoma. A primary unilateral surgical exploration remained unsuccessful to remove adenomatous parathyroid tissue and the pHPT persisted. 18F-ethylcholine PET/CT showed a left-sided retropharyngeal lesion with intense tracer uptake that could not be detected on US images at first sight. Therefore, additional 18F-ethylcholine PET/US fusion imaging was performed and revealed a poorly definable nodular structure on US that could be unambiguously correlated to the PET finding. Surgical excision confirmed an oncocytic variant of parathyroid adenoma, and parathormone and calcium levels normalized immediately.

Background: In addition to its SSTR-specific binding in tumors and healthy tissues, DOTATOC analogues accumulate in kidney parenchyma. Renal tracer uptake might be a surrogate of kidney function or dysfunction. This study aimed to evaluate if kidney function can be estimated from 68Ga[Ga]-DOTATOC uptake in PET/CT and its impact on the nephrotoxicity of 177Lu[Lu]-DOTATOC PRRT. Methods: Two cohorts of patients (A: 128 diagnostic patients; B: 32 PRRT patients) were evaluated retrospectively. SUV values of the kidneys, physiologically SSTR-expressing organs and in background compartments were assessed. Kidney function was calculated as eGFR by CKD-EPI creatinine equation. Pearson’s correlation coefficients and treatment-induced changes of uptake and kidney function were assessed and compared. Results: Kidney function and renal DOTATOC uptake showed a significant inverse correlation (R2 = 0.037; p = 0.029). Evaluated models of PET/CT measurements were not able to predict kidney function sufficiently. The uptake of other organs did not depend on eGFR. While the renal uptake increased after PRRT (p < 0.001), the kidney function did not change significantly (p = 0.382). Neither low pre-therapeutic eGFR nor high pre-therapeutic kidney uptake were risk factors of PRRT-induced deterioration in kidney function. Conclusion: The relevance of kidney function for renal 68Ga[Ga]-DOTATOC uptake is limited. The nephrotoxicity of 177Lu[Lu]-DOTATOC PRRT might be low and cannot be reliably predicted by pre-therapeutic measurements.

To proof the feasibility of manufacturing patient-indivdual (anthropomorphic) thyroid replicas from I-124 PET DICOM datasets by means of 3D printing. A possible field of application is the use of those phantoms for the calibration of gamma probes. After editing of the DICOM datasets using several software types and transferring into a dedicated stereolithography format, 10 fillable thyroid replicas (35-200 mL) made of polylactide acid were manufactured via 3D printing. All replicas were filled with a water-solution containing 3.5 MBq I-131 and applied to a standard neck phantom. Calibration factor measurements were carried out using a clinical gamma probe. Measurements were performed with three different tilts: + 15°, 0° and -15°. The influence of the replicas' volume and the tilt was investigated. Manufacturing of the replicas was successful in all cases. The time required for data processing was 13 ± 2 (median: 12, range: 9-25) min and 4-11 h for 3D printing (size-dependent). The printing process could be done overnight. Measured mean calibration factor for straight gamma probe positioning (0° tilt) was 31 965 ± 3360 (33 893, 25 470-34 253) cpm/MBq. A tilt of -15° resulted in lower calibration factors (-7.7 %), whereas a tilt of + 15° led to higher values (+ 9.5 %); p = 0.001. The calibration factors were highly inversely proportional correlated to the volume of the replicas (r = -0.91, p 0.001). 3D printing of patient-individual (anthropomorphic) fillable thyroid replicas was feasable for a large range of volumes. The study demonstrates the influence of the volume as well as the tilt of the measured object for calibration factor measurements with gamma probes.ZIEL: Diese Studie adressiert die Herstellung von patientenspezifischen (anthropomorphen) Schilddrüsenrepliken aus I-124-PET-DICOM-Datensätzen mittels eines handelsüblichen 3D-Druckers. Als mögliches Anwendungsgebiet wurden diese Phantome zur Kalibrierung von Gammamesssonden eingesetzt. Nach Aufbereitung der DICOM-Datensätze mittels mehrerer unterschiedlicher Computerapplikationen und Übertragung der Daten in ein spezielles Stereolithografie-Format, wurden 10 füllbare Schilddrüsenrepliken (Volumen: 35–200 ml) im 3D-Druckverfahren hergestellt. Alle Repliken wurden mit einer Wasserlösung (inklusive 3,5 MBq I-131) befüllt und in ein standardisiertes Halsphantom eingebracht. Es wurden Kalibrierfaktoren unter Verwendung einer klinischen Gammamesssonde ermittelt. Die Messungen wurden mit 3 verschiedenen Neigungen der Sonde durchgeführt: + 15°, 0° und –15°. Der Einfluss des Replikatvolumens und der Gammasondenneigung auf den Kalibrierungsfaktor wurde berechnet. Die Herstellung der Repliken war in allen Fällen erfolgreich. Die für die Datenverarbeitung erforderliche Zeit betrug 13 ± 2 (Median: 12, Bandbreite: 9–25) Minuten und 4–11 Stunden für den 3D-Druck (größenabhängig). Der 3D-Druck konnte über Nacht erfolgen. Der Kalibrierfaktor betrug bei gerader Sondenpositionierung (0° Neigung) 31 965 ± 3360 (33 893, 25 470–34 253) cpm/MBq. Eine Neigung von –15° führte zu niedrigeren Kalibrierfaktoren (–7,7 %), während eine Neigung von + 15° höhere Werte ergab (+ 9,5 %; p = 0,001). Es zeigte sich eine starke umgekehrte Proportionalität der Kalibrierfaktoren zum Volumen der Schilddrüsenrepliken (r = –0,91; p 0,001). Der 3D-Druck von patientenindividuellen (anthropomorphen) Schilddrüsenreplikaten war für eine große Bandbreite an Volumina möglich. Die Studie demonstrierte den Einfluss der Schilddrüsenvolumina sowie des Neigungswinkels auf die Messung von Kalibrierfaktoren mittels Gammasonden.

To investigate the interobserver agreement (IA) and the impact of consensus reading using four risk stratification systems for thyroid nodules (TN). Four experienced specialists independently rated US images of 80 TN according to the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines. The cases were randomly extracted from a prospectively acquired database (n > 1500 TN). The observers were blinded to clinical data. This study was divided into two sessions (S1 and S2) with 40 image sets each. After every session, a consensus reading was carried out (C1, C2). Subsequently, the effect of C1 was tested in S2 with 40 new cases followed by C2. Fleiss’ kappa (κ) was calculated for S1 and S2 to estimate the IA and learning curves. The results of C1 and C2 were used as reference for diagnostic accuracy calculations. IA significantly increased (p

To investigate the value of I-124 positron emission tomography (PET) / ultrasound (US) fusion imaging in comparison to conventional diagnostics (CD) of Thyroid nodules (TN) by multiple observers. Digital patient case files (PCF) of patients that received CD and I-124-PET/US in clinical routine were prepared containing cine-loops of the examinations. All physicians with nuclear medicine specialty from Germany, Austria, and Switzerland were invited to participate. 106 acquired observers completed 7.2 ± 1.8 (median: 8, range: 4-14) randomly assigned PCF (CD only or CD+PET/US). They assessed the TN function, stated their confidence in functional assessment, and suggested a treatment course for each TN. 68 PCF of 34 patients comprising 66 TN ≥ 1 cm (= 1.94 TN/patient) were created. A total of 748 (11.2/TN), and 751 ratings (11.4/TN) were recorded for CD only, and CD+PET/US, respectively. The functional assessment revealed more hyper- or hypofunctioning (524 vs. 320, p 0.0001) and less indifferent or not rateable (209 vs. 428, p 0.0001) TN in CD+PET/US vs. CD only. The observers' confidence in functional assessment was superior in CD+PET/US (p 0.0001). Furthermore, the ratings were carried out more homogeneous in CD+PET/US (p 0.0001). Fewer suggestion of follow up (p 0.0001), and more (p 0.0001) suggestion of invasive treatments (fine-needle aspirationsurgery) was observed in CD+PET/US. Radioiodine therapy was more often (p = 0.0036), and thyroid medication less often (p = 0.0167) advised in CD+PET/US. Functional assessment of equivocal TN shows frequent failures in CD, underestimating the incidence of hyper- and hypofunctioning lesions. Confidence in functional assessment significantly increases with additional PET/US. This influences the proposed treatment course.ZIEL: Multi-Observer-Untersuchung des diagnostischen Mehrwerts der I-124-Positronenemissionstomografie (PET)/Ultraschall (US) -Fusionsbildgebung im Vergleich zur konventionellen Diagnostik (CD) bei der Funktionsbeurteilung von Schilddrüsenknoten. Es erfolgte die Erstellung digitaler Patientenakten inklusive Filmsequenzen von Probanden, die im Rahmen der klinischen Routine sowohl mittels CD als auch I-124-PET/US untersucht wurden. Alle nuklearmedizinischen Ärzte aus Deutschland, Österreich und der Schweiz waren zur Teilnahme eingeladen. 106 Untersucher absolvierten jeweils 7,2 ± 1,8 (Median: 8, Bandbreite: 4–14) randomisiert zugewiesene digitale Patientenakten (CD oder CD+PET/US). Sie beurteilten die Funktion der Schilddrüsenknoten, ihre subjektive Sicherheit bei der Funktionsbeurteilung und schlugen einen Behandlungsverlauf vor. 68 digitale Patientenakten von 34 Patienten mit 66 Schilddrüsenknoten ≥ 1 cm (= 1,94 Knoten pro Patient) wurden erstellt. Insgesamt wurden 748 Bewertungen (11,2 pro Knoten) für CD und 751 Bewertungen (11,4 pro Knoten) für CD+PET/US dokumentiert. Bei CD+PET/US wurde die Funktion der Knoten im Vergleich zu CD häufiger als hyper- oder hypofunktionell (524 vs. 320; p 0,0001) und seltener als indifferent oder nicht bewertbar (209 vs. 428; p 0,0001) beurteilt. Die subjektive Sicherheit der Untersucher war bei CD+PET/US höher (p 0,0001) und die Funktionsbeurteilungen wurden mit größerer Homogenität abgegeben (p 0,0001). Bei CD+PET/US wurden im Vergleich zu CD weniger Verlaufskontrollen (p 0,0001), mehr invasive Behandlungen (FeinnadelaspirationOperation) (p 0,0001), häufiger Radioiodtherapien (p = 0,0036) und seltener medikamentöse Therapien (p = 0,0167) empfohlen. Die Funktion von Schilddrüsenknoten wird in der konventionellen Diagnostik häufig falsch beurteilt. Der Anteil hyper- oder hypofunktioneller Läsionen wird unterschätzt. Die subjektive Sicherheit bei der Funktionsbeurteilung steigt durch den Einsatz der I-124-PET/US. Diese Ergebnisse beeinflussen die vorgeschlagenen Behandlungsverläufe.

Purpose To evaluate the infusion dynamics and residual yttrium-90 activity during and after resin microsphere radioembolization with different injection techniques and initial activities. To assess the distribution of residual activity in the administration systems to allow optimization of the procedure and the equipment. Materials and Methods In a setup similar to that in standard clinical practice, radioembolization procedures were performed ex vivo. The influence of different injection techniques was assessed by comparing pulsatile and continuous injections. The influence of the absolute amount of activity to the residual activity was assessed by comparing pulsatile 0.5-GBq- with 1.0-GBq-procedures. Continuous dose rate measurements were performed. Activity distribution was determined by positron-emission tomography (PET)/CT. Results Fifteen procedures were performed: 5 pulsatile 0.5-GBq-, 5 continuous 0.5-GBq-, and 5 pulsatile 1.0-GBq-procedures. Mean residual activity was 4.0% ± 1.7% (range 1.2%–6.6%), without statistically significant differences between injection techniques (P = .841) or between prescribed activities (P = .222). Dose-rate measurements revealed an exponential decrease of the activities in the vials with high variability. Activity fell rapidly to 32% ± 7.9% (range 23%–55%) after injection of 4 of 20 mL 5% dextrose solution. Residual activity accumulations were identified at the 3-way stopcock (100% of procedures), in the C-line (80%), at the microcatheter connector (20%), and in the A-line (6.7%), but not in the vials. Conclusions Residual activity in a commercial administration system for resin microsphere radioembolization is variable and does not systematically depend on initial yttrium-90 activity or on injection technique. Predilection sites for residual activity were identified, which should receive special attention when performing resin transarterial radioembolization procedures, and for further administration system developments.

SIRT is an established treatment option for liver malignancies. Metabolic information can provide additional knowledge about tumoral characteristics and treatment response. FDG-PET/CT was shown to be advantageous for pre-/post-SIRT evaluation. However, whole-body PET/CT is an elaborate procedure. The aim of the study was to optimize clinical efficacy assessment after SIRT with a low-dose, low-cost protocol for focused diagnostic work-up. An abdomen-only minimal-activity FDG-PET/CT protocol (MA-PET) was established as an alternative for clinically indicated whole-body PET/CT scans. After administering 40 MBq of F-18-FDG one bed position was scanned for 15 minutes. Scans were acquired before (initial scan), one month after (interim scan) and three months after SIRT (follow-up scan). Metabolic tumor activity was evaluated and was compared to standard CT follow-up results. 50 lobar SIRT procedures in 37 patients were analysed. HCC (28), hepatic metastases (15) and CCC (7) were treated. In 18 liver lobes initial MA-PET did not show hypermetabolic lesions, 32 liver lobes underwent interim and follow-up MA-PET. All 114 MA-PET were technically feasible. Mean radiation dose was 1.9 mSv. 64 % of HCC presented low metabolism at baseline, whereas metastases and CCC were all clearly PET-positive. Majority of radiated liver tumors showed at least partial metabolic response. PET/CT results diverged from follow-up CT in 63 % of cases. Minimal-Activity FDG-PET/CT of the liver is a feasible tool for efficacy assessment after SIRT with low financial and radiation burden. It provides additional information to morphologic imaging modalities, which can be helpful in response appraisal and treatment planning.ZIEL: Die FDG-PET/CT erwies sich im Rahmen der SIRT als gewinnbringend für die prä- und posttherapeutische Diagnostik. Dennoch wird diese aufgrund des hohen Aufwands häufig nicht angewendet. Ziel unserer Untersuchung war die Optimierung der Therapiekontrolle nach SIRT mittels eines fokussierten, kostensparenden Niedrigdosis-PET-Protokolls. Ein Oberbauch-zentriertes, Minimal-Aktivitäts-FDG-PET/CT-Protokoll (MA-PET) wurde für klinisch indizierte Untersuchungen etabliert. Nach Injektion von 40 MBq F-18-FDG wurde eine Bettposition über 15 Minuten akquiriert. Die MA-PET wurden einen Tag vor, einen Monat nach und drei Monate nach SIRT durchgeführt. Das metabolische Therapieansprechen wurde ermittelt und mit der CT-Verlaufskontrolle verglichen. 50 lobäre SIRT-Prozeduren, darunter 28 HCC, 15 hepatische Metastasen und 7 CCC, wurden betrachtet. Von 37 eingeschlossenen Patienten erhielten 13 eine zusätzliche SIRT der Gegenseite. Alle Metastasen und CCC waren PET-positiv, 64 % der HCC hingegen initial PET-negativ. 32 Leberlappen mit initial hypermetabolen Läsionen wurden mittels MA-PET verlaufskontrolliert. Alle 114 MA-PET waren technisch durchführbar. Die mittlere Strahlenbelastung pro Untersuchung lag bei 1,9 mSv. Die Mehrheit der Lebertumoren zeigte mindestens ein partielles Therapieansprechen, wobei sich die MA-PET-Ergebnisse in 63 % der Fälle von denen der Standard-CT unterschieden. MA-PET der Leber ist ein zuverlässiges und geeignetes Verfahren zur Beurteilung der SIRT-Wirksamkeit, mit welchem Strahlenbelastung und Kosten eingespart werden können. Im Vergleich zur morphologischen Bildgebung werden auch mit dem neu etablierten Protokoll zusätzliche Informationen gewonnen, die für Verlaufskontrolle und Therapieplanung nützlich sein können.

Both, ultrasonography but also radionuclide imaging using [99mTc]Pertechnetate or radioactive iodine isotopes are essential tools used during the diagnostic workup of hyperthyroidism with or without structural alterations of the thyroid. Colour duplex sonography and ultrasound elastography may add important information in order to find the cause of the hormone excess. During the last years, also hybrid imaging using SPECT/-(CT) or PET-based methods, such as [124]Iodine-PET/CT or [124]Iodine-PET/ultrasound also have nodularbeen increasingly used and especially play a role in the context of localizing ectopic thyroid tissue or in multinodular goiter. Recently also promising data has been published on the use of [99mTc]MIBI imaging in amiodarone induced hyperthyroidism.

PET/CT with prostate-specific membrane antigen (PSMA)-targeted tracers has been used in the diagnosis and staging of patients with clear cell renal cell carcinoma (ccRCC). For ccRCC primary tumors, PET parameters were shown to predict histologic grade and features. The aim of this study was to correlate PSMA PET/CT with histopathological findings in patients with metastatic recurrence of ccRCC. Patients with ccRCC who underwent PSMA-targeted PET/CT and subsequent histopathological evaluation of suspicious lesions were included. Specimens underwent immunohistochemical marking. Lesion diameter, volume and tracer uptake were correlated with the extent and intensity of molecular PSMA expression and with clinical findings. Twelve PET-positive lesions of nine patients were evaluated. Eleven ccRCC metastases and one prostate carcinoma were detected histopathologically. Molecular PSMA expression was detected in all lesions, which intensity and distribution did not correlate with PET parameters. PSMA-targeted PET/CT is a feasible tool for the evaluation of patients with ccRCC but cannot reliably predict histologic features of metastases. PSMA may also be expressed in malignant lesions other than ccRCC, leading to incidental detection of these tumors.

Short-term follow-up examinations could verify ambiguous findings in PET/CT diagnostics, but are often avoided due to radiation and financial burdens. We demonstrate the feasibility of a focused, minimal-activity PET protocol as a supplemental examination for uncertain findings after standard PET/CT. After changing conditions, e.g. patient positioning, preparation and bypassing an interval as well as a targeted tracer change, an additional examination with less than 1 mSv of additional radiation exposure was performed. Lowered administered activity of radiopharmaceuticals could be compensated by prolonged acquisition time, which was made possible by the limitation to a single body region. A sufficient visual and quantitative image quality of scans could be achieved. In all cases, the ambiguous finding could be clarified, so further diagnostic procedures or unnecessary interventions were avoided.