Update of the competence-based catalog of learning objectives in nuclear medicine for the study of human medicine in Germany

AIM

To update the subject-specific, competence-based catalog of learning objectives for medical studies in Germany published by the German Society of Nuclear Medicine (DGN) in 2018, prioritizing relevant learning objectives.

METHODS

Based on the previous catalog, the writing group compiled nuclear medicine topics and formulated competence-based learning objectives, including medical developments, device innovations and new radiopharmaceutical approvals. These were presented for prioritization to the 180 habilitated DGN members as an expert group in a Delphi process. The first round of voting assessed firstly the topics in terms of necessity or dispensability, and secondly the detailed learning objectives of the topics were assessed for their relevance to academic teaching in nuclear medicine. The results of the first survey were used to draft a catalog of learning objectives with final approval by the expert group in a second survey. The time available for teaching nuclear medicine was also recorded.

RESULTS

The writing group developed 240 competence-based learning objectives from 41 topics. After a first Delphi round, 73 detailed competence-based learning objectives from 15 topics were compiled. The mean teaching time was 8.4 h for lectures, 3.7 h for seminars and 3.6 h for practical courses. In a second Delphi round, the agreement of the expert group was at least 95% for the selected topics and at least 90% for the detailed learning objectives.

SUMMARY

The catalog of subject-specific learning objectives, updated by expert consensus, provides basic knowledge, skills and competences related to the most relevant diagnostic and therapeutic procedures in nuclear medicine, taking into account both long-established topics and recently introduced innovations.

Artificial Intelligence and Deep Learning for Advancing PET Image Reconstruction: State-of-the-Art and Future Directions

Positron emission tomography (PET) is vital for diagnosing diseases and monitoring treatments. Conventional image reconstruction (IR) techniques like filtered backprojection and iterative algorithms are powerful but face limitations. PET IR can be seen as an image-to-image translation. Artificial intelligence (AI) and deep learning (DL) using multilayer neural networks enable a new approach to this computer vision task. This review aims to provide mutual understanding for nuclear medicine professionals and AI researchers. We outline fundamentals of PET imaging as well as state-of-the-art in AI-based PET IR with its typical algorithms and DL architectures. Advances improve resolution and contrast recovery, reduce noise, and remove artifacts via inferred attenuation and scatter correction, sinogram inpainting, denoising, and super-resolution refinement. Kernel-priors support list-mode reconstruction, motion correction, and parametric imaging. Hybrid approaches combine AI with conventional IR. Challenges of AI-assisted PET IR include availability of training data, cross-scanner compatibility, and the risk of hallucinated lesions. The need for rigorous evaluations, including quantitative phantom validation and visual comparison of diagnostic accuracy against conventional IR, is highlighted along with regulatory issues. First approved AI-based applications are clinically available, and its impact is foreseeable. Emerging trends, such as the integration of multimodal imaging and the use of data from previous imaging visits, highlight future potentials. Continued collaborative research promises significant improvements in image quality, quantitative accuracy, and diagnostic performance, ultimately leading to the integration of AI-based IR into routine PET imaging protocols.

18F-FDG PET/CT-derived total lesion glycolysis predicts abscess formation in patients with surgically confirmed infective endocarditis: Results of a retrospective study at a tertiary center

BACKGROUND

Abnormal activity of 18F-FDG PET/CT is a major Duke criterion in the diagnostic work-up of infective prosthetic valve endocarditis (IE). We hypothesized that quantitative lesion assessment by 18F-FDG PET/CT-derived standard maximum uptake ratio (SURmax), metabolic volume (MV), and total lesion glycolysis (TLG) might be useful in distinct subgroups of IE patients (e.g. IE-related abscess formation).

METHODS

All patients (n = 27) hospitalized in our tertiary IE referral medical center from January 2014 to October 2018 with preoperatively performed 18F-FDG PET/CT and surgically confirmed IE were included into this retrospective analysis.

RESULTS

Patients with surgically confirmed abscess formation (n = 10) had significantly increased MV (by ~ fivefold) and TLG (by ~ sevenfold) as compared to patients without abscess (n = 17). Receiver operation characteristics (ROC) analyses demonstrated that TLG (calculated as MV × SURmean, i.e. TLG (SUR)) had the most favorable area under the ROC curve (0.841 [CI 0.659 to 1.000]) in predicting IE-related abscess formation. This resulted in a sensitivity of 80% and a specificity of 88% at a cut-off value of 14.14 mL for TLG (SUR).

CONCLUSION

We suggest that 18F-FDG PET/CT-derived quantitative assessment of TLG (SUR) may provide a novel diagnostic tool in predicting endocarditis-associated abscess formation.

The Medical Informatics Initiative and the Network University Medicine - Perspectives for Nuclear Medicine

Digitization in the healthcare sector and the support of clinical workflows with artificial intelligence (AI), including AI-supported image analysis, represent a great challenge and equally a promising perspective for preclinical and clinical nuclear medicine. In Germany, the Medical Informatics Initiative (MII) and the Network University Medicine (NUM) are of central importance for this transformation. This review article outlines these structures and highlights their future role in enabling privacy-preserving federated multi-center analyses with interoperable data structures harmonized between site-specific IT infrastructures. The newly founded working group "Digitization and AI" in the German Society of Nuclear Medicine (DGN) as well as the Fach- und Organspezifische Arbeitsgruppe (FOSA, specialty- and organ-specific working group) founded for the field of nuclear medicine (FOSA Nuklearmedizin) within the NUM aim to initiate and coordinate measures in the context of digital medicine and (image-)data-driven analyses for the DGN.

Head-to-Head Comparison of Dual-Source and Split-Beam Filter Multi-Energy CT versus SPECT/CT for Assessing Lobar Lung Perfusion in Emphysema

Purpose

To evaluate dual-source and split-beam filter multi-energy chest CT in assessing pulmonary perfusion on a lobar level in patients with lung emphysema, using perfusion SPECT as the reference standard.

Materials and Methods

Patients with emphysema evaluated for lung volume reduction therapy between May 2016 and February 2021 were retrospectively included. All patients underwent SPECT and either dual-source or split-beam filter (SBF) multi-energy CT. To calculate the fractional lobar lung perfusion (FLLP), SPECT acquisitions were co-registered with chest CT scans (hereafter, SPECT/CT) and semi-manually segmented. For multi-energy CT scans, lung lobes were automatically segmented using a U-Net model. Segmentations were manually verified. The FLLP was derived from iodine maps computed from the multi-energy data. Statistical analysis included Pearson and intraclass correlation coefficients and Bland-Altman analysis.

Results

Fifty-nine patients (30 male, 29 female; 31 underwent dual-source CT, 28 underwent SBF CT; mean age for all patients, 67 years ± 8 [SD]) were included. Both multi-energy methods significantly correlated with the SPECT/CT acquisitions for all individual lobes (P < .001). Pearson correlation concerning all lobes combined was significantly better for dual-source (r = 0.88) than for SBF multi-energy CT (r = 0.78; P = .006). On the level of single lobes, Pearson correlation coefficient differed for the right upper lobe only (dual-source CT, r = 0.88; SBF CT, r = 0.58; P = .008).

Conclusion

Dual-source and SBF multi-energy CT accurately assessed lung perfusion on a lobar level in patients with emphysema compared with SPECT/CT. The overall correlation was higher for dual-source multi-energy CT.Keywords: Chronic Obstructive Pulmonary Disease, Comparative Studies, Computer Applications, CT Spectral Imaging, Image Postprocessing, Lung, Pulmonary Perfusion© RSNA, 2023.

Diffuse Large B-Cell Lymphoma and Related Entities

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the most common malignant B-cell neoplasm, with an incidence of 5.6 per 100 000 persons per year and a mean age of onset of approximately 65 years. It is an aggressive type of non-Hodgkin's lymphoma requiring urgent treatment with curative intent. Evidence-based guidelines have not been available to date.

METHODS

For this first international evidence-based DLBCL-specific guideline, various systematic literature searches were performed. 5 systematic reviews, 21 randomized controlled trials (RCTs), and 36 non-randomized studies were used to formulate 42 recommendations. 142 were formulated on the basis of expert consensus. All recommendations were approved in a structured consensus-finding process.

RESULTS

For staging, combined positron emission tomography and computed tomography (PET/CT) should be performed (evidence: a prospective registry study). For all patients with a new diagnosis of DLBCL and without contraindications, R-CHOP based immunochemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) should be initiated with curative intent (evidence: RCTs). The individual treatment strategy is tailored to the patient's age and risk constellation. Once immunochemotherapy has been completed, PET/CT should be performed again to check for remission. Patients with PET-positive residual disease that is amenable to radiotherapy should be treated with consolidating irradiation (evidence: retrospective cohort study).

CONCLUSION

This clinical practice guideline on the diagnosis, treatment, and followup of patients with DLBCL and related entities provides a standardized clinical management approach, identifies areas where improvement would be desirable, and can serve as a basis for the development of further studies.

Infective Endocarditis: Predictive Factors for Diagnosis and Mortality in Surgically Treated Patients

Background: Diagnosis of infective endocarditis (IE) often is challenging, and mortality is high in such patients. Our goal was to characterize common diagnostic tools to enable a rapid and accurate diagnosis and to correlate these tools with mortality outcomes. Methods: Because of the possibility of including perioperative diagnostics, only surgically treated patients with suspected left-sided IE were included in this retrospective, monocentric study. A clinical committee confirmed the diagnosis of IE. Results: 201 consecutive patients (age 64 ± 13 years, 74% male) were finally diagnosed with IE, and 14 patients turned out IE-negative. Preoperative tests with the highest sensitivity for IE were positive blood cultures (89.0%) and transesophageal echocardiography (87.5%). In receiver operating characteristics, vegetation size revealed high predictive power for IE (AUC 0.800, p < 0.001) with an optimal cut-off value of 11.5 mm. Systemic embolism was associated with mortality, and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) had predictive power for mortality. Conclusion: If diagnostic standard tools remain inconclusive, we suggest employing novel cut-off values to increase diagnostic accuracy and accelerate diagnosis. Patients with embolism or elevated NT-proBNP deserve a closer follow-up.

Development of a Neurotensin-Derived 68Ga-Labeled PET Ligand with High In Vivo Stability for Imaging of NTS1 Receptor-Expressing Tumors

Overexpression of the neurotensin receptor type 1 (NTS1R), a peptide receptor located at the plasma membrane, has been reported for a variety of malignant tumors. Thus, targeting the NTS1R with 18F- or 68Ga-labeled ligands is considered a straightforward approach towards in vivo imaging of NTS1R-expressing tumors via positron emission tomography (PET). The development of suitable peptidic NTS1R PET ligands derived from neurotensin is challenging due to proteolytic degradation. In this study, we prepared a series of NTS1R PET ligands based on the C-terminal fragment of neurotensin (NT(8–13), Arg8-Arg9-Pro10-Tyr11-Ile12-Leu13) by attachment of the chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) via an Nω-carbamoylated arginine side chain. Insertion of Ga3+ in the DOTA chelator gave potential PET ligands that were evaluated concerning NTS1R affinity (range of Ki values: 1.2–21 nM) and plasma stability. Four candidates were labeled with 68Ga3+ and used for biodistribution studies in HT-29 tumor-bearing mice. [68Ga]UR-LS130 ([68Ga]56), containing an N-terminal methyl group and a β,β-dimethylated tyrosine instead of Tyr11, showed the highest in vivo stability and afforded a tumor-to-muscle ratio of 16 at 45 min p.i. Likewise, dynamic PET scans enabled a clear tumor visualization. The accumulation of [68Ga]56 in the tumor was NTS1R-mediated, as proven by blocking studies.

Case Report: Extramedullary Acute Promyelocytic Leukemia: An Unusual Case and Mini-Review of the Literature

Background

Acute promyelocytic leukemia (APL) constitutes a serious hematological emergency necessitating rapid diagnosis and therapy to prevent lethal bleedings resulting from APL-induced thrombocytopenia and coagulopathy. Atypical manifestations of APL, such as extramedullary disease at first presentation, pose diagnostic challenges and delay the onset of appropriate therapy. Nevertheless, extramedullary manifestations of APL are mostly accompanied by blood count alterations pointing to an underlying hematological disease. In this report, we present the first case of APL bearing close resemblance to a metastasized laryngeal carcinoma with normal blood counts and absent coagulopathy.

Case Presentation

A 67-year-old man with a previous history of smoking was admitted to our hospital with progressive hoarseness of voice, odynophagia, dysphagia and exertional dyspnea. Laryngoscopy revealed a fixed right hemi larynx with an immobile right vocal fold. Imaging of the neck via magnetic-resonance imaging (MRI) and positron emission tomography–computed tomography (PET/CT) with F-18-fluordeoxyglucose (FDG) showed a large hypermetabolic tumor in the right piriform sinus and tracer uptake in adjacent lymph nodes, highly suspicious of metastasized laryngeal carcinoma. Surprisingly the histological examination revealed an extramedullary manifestation of acute promyelocytic leukemia. Remarkably, blood counts and coagulation parameters were normal. Moreover, no clinical signs of hemorrhage were found. PML-RARA fusion was detected in both laryngeal mass and bone marrow. After diagnosis of APL, ATRA-based chemotherapy was initiated resulting in complete remission of all APL manifestations.

Conclusions

This is the first case report of APL initially presenting as laryngeal chloroma. Additionally, we performed a comprehensive literature review of previously published extramedullary APL manifestations. In aggregate, a normal blood count at first presentation constitutes an extremely rare finding in patients initially presenting with extramedullary APL manifestations.

Diagnostic value of FDG PET/CT imaging in patients with surgically managed infective endocarditis: results of a retrospective analysis at a tertiary center

BACKGROUND

We assessed the diagnostic value of FDG PET/CT in a real-world cohort of patients with surgically managed infective endocarditis (IE).

METHODS

We performed a retrospective analysis of all patients hospitalized in a tertiary IE referral medical center from January 2014 to October 2018 fulfilling the following criteria: ICD-10 code for IE and OPS code for both, heart surgery and FDG PET/CT.

RESULTS

Final analysis included 29 patients, whereof 28 patients had surgically proven IE. FDG PET/CT scan was true-positive in 15 patients (sensitivity (SEN) 56%) and false-negative in 12 patients. Combination of Duke criteria (DC) with FDG PET/CT scan resulted in gain of SEN for all patients with confirmed IE (SEN of DC 79% vs SEN of combination DC and FDG PET/CT 89%), driven by a relevant gain in PVE patients only (SEN of DC 78% vs SEN of combination DC and FDG PET/CT 94%). Interestingly, higher prosthesis age was observed in patients with false-negative scans.

CONCLUSIONS

We found a SEN of 56% for FDG PET/CT in a real-world cohort of patients with surgically proven IE which was associated with a 16% gain of IE diagnosis in patients with PVE when combined with DC.

Radiation doses from low-dose CT scans in SPECT/CT and PET/CT examinations: A survey in Germany

AIM

Recently, dose reference levels (DRLs) have been defined in Germany for auxiliary low-dose CT scans in hybrid SPECT/CT and PET/CT examinations, based on data from 2016/17. Here, another survey from 2020 was evaluated and compared with the new DRLs as well as with similar surveys from foreign countries.

METHODS

The survey, which had already been conducted in the Nordic countries, queried for various examinations including the following values: patient weight and height, volume CT dose index (CTDI_vol), dose length product (DLP). For each examination, statistical parameters such as the third quartile (Q3) were determined from all submitted CTDI_vol and DLP values. Additionally, for examinations comprising datasets from at least 10 systems, the third quartile (Q3-Med) of the respective median values of each system was calculated. Q3 and Q3-Med were compared with the newly published DRLs from Germany and values from similar studies from other countries.

RESULTS

Data from 15 SPECT/CT and 13 PET/CT systems from 15 nuclear medicine departments were collected. For the following examinations datasets from more than 10 systems were submitted: SPECT lung VQ, SPECT bone, SPECT&PET cardiac, PET brain, PET oncology. Especially for examinations of the thorax and heart, the new DRLs are very strict compared to this study. The CTDI_vol values for examinations of the head were lower in this study than the DRLs prescribe now.

CONCLUSIONS

For certain examination types, there is a need for dose optimization at some clinics and devices in order to take into account the new DRLs in Germany in the future.

Dose estimates of occupational radiation exposure during radioguided surgery of Tc-99m-PSMA-labeled lymph nodes in recurrent prostate cancer

AIM

 [^99mTc]Tc-PSMA-based radioguided surgery (TPRS) represents a curative approach for localized relapse of prostate cancer. For its simplified regulatory permission, the radiation protection authorities require a ^99mTc- activity below the exemption limit of 10 MBq at the time of surgery. Our aim was to determine the optimal amount of radioactivity (OAR) to comply with that limit and to estimate the maximum number of TPRS procedures per year and surgeon without triggering the full monitoring obligations.

METHODS

 In this retrospective study, a dose rate meter was calibrated using measurements on phantoms and from recently injected (1 min p. i.) patients to determine the activity in the patient from measured dose rates. The effective half-life of ^99mTc-PSMA-I&S in patients was determined from repeated dose rate measurements to estimate dose parameters of relevance for radiation protection. External exposures of the surgeons were measured with personal dosimeters calibrated in H_p(10). The surgeon's finger dose H_p(0.07) is estimated from radioactivity measured in resected lymph nodes. Potenzial incorporations were estimated for an activity of 10 MBq.

RESULTS

 From the first 6 subsequent patients, an effective half-life of 4.15 h was observed. Assuming an operation time 24 h p. i., the OAR was 550 MBq. Operations lasting in average 2 h in a distance of 0.25 m to the patient imply a body dose for surgeons of 4.16 µSv per procedure. Based on these estimates, the surgeon's H_p(10) is less than 1 mSv per year with up to 241 operations per year. H_p(0.07) and potential incorporation of activity do not lead to further limitations.

SUMMARY

 All radiation protection regulations are met with adherence to OAR recommended here without triggering the full monitoring obligations from radiation protection regulations.

FDG PET/CT to detect bone marrow involvement in the initial staging of patients with aggressive non-Hodgkin lymphoma: results from the prospective, multicenter PETAL and OPTIMAL>60 trials

PURPOSE

Fluorine-18 fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG PET/CT) is the standard for staging aggressive non-Hodgkin lymphoma (NHL). Limited data from prospective studies is available to determine whether initial staging by FDG PET/CT provides treatment-relevant information of bone marrow (BM) involvement (BMI) and thus could spare BM biopsy (BMB).

METHODS

Patients from PETAL (NCT00554164) and OPTIMAL>60 (NCT01478542) with aggressive B-cell NHL initially staged by FDG PET/CT and BMB were included in this pooled analysis. The reference standard to confirm BMI included a positive BMB and/or FDG PET/CT confirmed by targeted biopsy, complementary imaging (CT or magnetic resonance imaging), or concurrent disappearance of focal FDG-avid BM lesions with other lymphoma manifestations during immunochemotherapy.

RESULTS

Among 930 patients, BMI was detected by BMB in 85 (prevalence 9%) and by FDG PET/CT in 185 (20%) cases, for a total of 221 cases (24%). All 185 PET-positive cases were true positive, and 709 of 745 PET-negative cases were true negative. For BMB and FDG PET/CT, sensitivity was 38% (95% confidence interval [CI]: 32-45%) and 84% (CI: 78-88%), specificity 100% (CI: 99-100%) and 100% (CI: 99-100%), positive predictive value 100% (CI: 96-100%) and 100% (CI: 98-100%), and negative predictive value 84% (CI: 81-86%) and 95% (CI: 93-97%), respectively. In all of the 36 PET-negative cases with confirmed BMI patients had other adverse factors according to IPI that precluded a change of standard treatment. Thus, the BMB would not have influenced the patient management.

CONCLUSION

In patients with aggressive B-cell NHL, routine BMB provides no critical staging information compared to FDG PET/CT and could therefore be omitted.

TRIAL REGISTRATION

NCT00554164 and NCT01478542.

Biomodulatory Treatment Regimen, MEPED, Rescues Relapsed and Refractory Classic Hodgkin's Disease

Introduction: Current combined intensive chemotherapy and radiation regimens yield excellent survival rates in advanced classic Hodgkin’s lymphoma (cHL). However, acute toxicity in elderly, comorbid patients can be challenging and long-term survival in refractory patients remains poor.

Patients and Methods: We report on six patients with r/r HL, three patients with long-term follow-up, three newly treated, after biomodulatory therapy. All patients received MEPED (treosulfan 250 mg p.o. daily, everolimus 15 mg p.o. daily to achieve serum trough levels of 15 ng/ml, pioglitazone 45 mg p.o. daily, etoricoxib 60 mg p.o. daily and dexamethasone 0.5 mg p.o. daily). Patients had either received every at that time approved systemic treatment or were ineligible for standard treatment, including immune checkpoint inhibition (ICPi) due to prior demyelinating autoimmune polyneuropathy, myasthenia gravis and previous allogeneic hematopoietic-stem-cell transplant (alloHSCT). Medication was administered continuously from day 1. One patient with relapse after alloHSCT received trofosfamide 50 mg daily instead of treosulfan to avoid risk of increased myelotoxicity. The patients were treated in individual healing attempts outside a clinical trial after institutional review board approval. ¹⁸F-fluoro-2-deoxy-d-glucose positron emission tomography combined with computed tomography scan (FDG-PET/CT) was performed to monitor treatment and follow-up.

Results: In the three newly treated patients, CT scans showed partial remissions after 2–5 months on MEPED treatment. Two patients had achieved PET Deauville score 2 and 3, while the third remained positive at Deauville score 5. One patient achieving PR became eligible for alloHSCT, while the other two patients continued treatment with MEPED. All patients eventually achieved continuous complete remission (cCR), one after consecutive alloHSCT, one after discontinuing MEPED consolidation for >1 year and one on on-going MEPED consolidation, respectively. Only one patient experienced Grade 3 toxicity (bacterial pneumonia) requiring temporary discontinuation of MEPED for 10 days. All three previously published patients received allo HSCT for consolidation and have achieved cCR.

Conclusions: MEPED is well tolerated with low toxicity and highly efficacious in relapsed/refractory cHL, including severely comorbid patients. Due to its immunomodulatory components, MEPED might also have a synergistic potential when combined with ICPi but requires further evaluation within a clinical trial.

Virus-specific memory T cell responses unmasked by immune checkpoint blockade cause hepatitis

Treatment of advanced melanoma with combined PD-1/CTLA-4 blockade commonly causes serious immune-mediated complications. Here, we identify a subset of patients predisposed to immune checkpoint blockade-related hepatitis who are distinguished by chronic expansion of effector memory CD4⁺ T cells (T_EM cells). Pre-therapy CD4⁺ T_EM cell expansion occurs primarily during autumn or winter in patients with metastatic disease and high cytomegalovirus (CMV)-specific serum antibody titres. These clinical features implicate metastasis-dependent, compartmentalised CMV reactivation as the cause of CD4⁺ T_EM expansion. Pre-therapy CD4⁺ T_EM expansion predicts hepatitis in CMV-seropositive patients, opening possibilities for avoidance or prevention. 3 of 4 patients with pre-treatment CD4⁺ T_EM expansion who received αPD-1 monotherapy instead of αPD-1/αCTLA-4 therapy remained hepatitis-free. 4 of 4 patients with baseline CD4⁺ T_EM expansion given prophylactic valganciclovir and αPD-1/αCTLA-4 therapy remained hepatitis-free. Our findings exemplify how pathogen exposure can shape clinical reactions after cancer therapy and how this insight leads to therapeutic innovations.

Total lesion glycolysis in oral squamous cell carcinoma as a biomarker derived from pre-operative FDG PET/CT outperforms established prognostic factors in a newly developed multivariate prediction model

PURPOSE

Retrospective study to investigate the impact of image derived biomarkers from [¹⁸F]FDG PET/CT prior to surgical resection in patients with initial diagnosis of oral squamous cell carcinoma (OSCC), namely SUV_max, SUV_mean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of the primary tumor to predict overall survival (OS).

MATERIALS AND METHODS

127 subsequent patients with biopsy-proven OSCC were included who underwent [¹⁸F]FDG PET/CT before surgery. SUV_max, SUV_mean, MTV and TLG of the primary tumor were measured. OS was estimated according to Kaplan-Meier and compared between median-splitted groups by the log-rank test. Prognostic parameters were analyzed by uni-/multivariate Cox-regression.

RESULTS

During follow-up 52 (41%) of the patients died. Median OS was longer for patients with lower MTV or lower TLG. SUV_max and SUV_mean failed to be significant predictors for OS. Univariate Cox-regression identified MTV, TLG, lymph node status and UICC stage as prognostic factors. By multivariate Cox-regression MTV and TLG turned out to be independent prognostic factors for OS.

CONCLUSIONS

The pre-therapeutic [¹⁸F]FDG PET/CT parameters MTV and TLG in the primary tumor are prognostic for OS of patients with an initial diagnosis of OSCC. TLG is the strongest independent prognostic factor for OS and outperforms established prognostic parameters in OSCC.

Candida Endocarditis in Patients with Candidemia: A Single-Center Experience of 14 Cases

A retrospective, single-center analysis of 14 cases of Candida endocarditis (from 355 candidemia cases during the years 2012–2019) revealed a high in-hospital mortality (57.1%), a high proportion of healthcare-associated infections (13/14) and a high treatment preference for echinocandins. Transthoracic echocardiography and ¹⁸F-FDG PET/CT had a sensitivity of 54.5% and 57.1%, respectively. Patients were older than previously described and most patients with Candida endocarditis had persistent candidemia for ≥ 3 days despite antifungal therapy.

CXCR4-Targeted PET Imaging of Central Nervous System B-Cell Lymphoma

C-X-C chemokine receptor 4 (CXCR4) is a transmembrane chemokine receptor involved in growth, survival, and dissemination of cancer, including aggressive B-cell lymphoma. MRI is the standard imaging technology for central nervous system (CNS) involvement of B-cell lymphoma and provides high sensitivity but moderate specificity. Therefore, novel molecular and functional imaging strategies are urgently required. Methods: In this proof-of-concept study, 11 patients with lymphoma of the CNS (8 primary and 3 secondary involvement) were imaged with the CXCR4-directed PET tracer ⁶⁸Ga-pentixafor. To evaluate the predictive value of this imaging modality, treatment response, as determined by MRI, was correlated with quantification of CXCR4 expression by ⁶⁸Ga-pentixafor PET in vivo before initiation of treatment in 7 of 11 patients. Results: ⁶⁸Ga-pentixafor PET showed excellent contrast with the surrounding brain parenchyma in all patients with active disease. Furthermore, initial CXCR4 uptake determined by PET correlated with subsequent treatment response as assessed by MRI. Conclusion: ⁶⁸Ga-pentixafor PET represents a novel diagnostic tool for CNS lymphoma with potential implications for theranostic approaches as well as response and risk assessment.

FDG-PET Imaging for Hodgkin and Diffuse Large B-Cell Lymphoma-An Updated Overview

Since the mid-1990s, ¹⁸F-fluorodeoxglucose (FDG)-positron emission tomography (PET) in combination with computed tomography has come to play a prominent role in the management of malignant lymphomas. One of the first PET applications in oncology was the detection of lymphoma manifestations at staging, where it has shown high sensitivity. Nowadays, this imaging modality is also used during treatment to evaluate the individual chemosensitivity and adapt further therapy accordingly. If the end-of-treatment PET is negative, irradiation in advanced-stage Hodgkin lymphoma patients can be safely omitted after highly effective chemotherapy. Thus far, lymphoma response assessment has mainly been performed using visual criteria, such as the Deauville five-point scale, which became the international standard in 2014. However, novel measures such as metabolic tumor volume or total lesion glycolysis have recently been recognized by several working groups and may further increase the diagnostic and prognostic value of FDG-PET in the future.

[PET/CT and PET/MRI in Head and Neck Cancer]

Positron emission tomography (PET) with ¹⁸F-fluordeoxyglucose (FDG) in combination with computed tomography (CT) is well established for the diagnostic work-up of patients with head and neck cancer. Possible applications include the detection of an occult primary tumor metastatic to cervical nodes, locoregional staging, assessment of treatment response to external beam irradiation (also in combination with chemotherapy), and surveillance for recurrence. The success of high-precision irradiation techniques such as intensity-modulated radiation therapy (IMRT) appears to be improved by delineating the tumor volume using PET/CT. Combined PET/Magnetic Resonance Imaging (MRI) offers advantages in staging with regard to increased anatomical details and radiation dose reduction but is inferior to PET/CT in the detection of pulmonary metastases and secondary tumors. As shown by a randomized trial in patients with advanced head and neck cancer, neck dissection can be omitted if FDG PET/CT is negative after radiochemotherapy and survival is not compromised. With this high level of evidence PET/CT in head and neck cancer currently found its way into the catalog of diagnostic procedures for patients in the statutory health insurances.

[Evaluation of intratherapeutic 177Lu-HA-DOTATATE treatment in neuroendocrine tumors: dosimetry with SPECT, whole-body imaging and gamma probe]

AIM

 Peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-HA-DOTATATE has evolved as a new path in the treatment of somatostatin-receptor-expressing neuroendocrine tumors. The kidneys are proven as organs at risk and should be evaluated dosimetrically. Overlap with other organs will make dosimetry based on planar scintigraphy inaccurate. Aim of this study was to approximate the contribution of the kidneys to conjugated planar views without the use of a SPECT/CT.

MATERIAL AND METHOD

 An algorithm was developed to determine the kidney dose using an EXCEL (Microsoft) based program. Dosimetric data were drawn and merged from three modalities: an individually calibrated gamma probe, a whole-body scintigraphy (WBS) and SPECT-acquisitions. The method was evaluated for 85 kidneys. Kidney masses were obtained via CT volumetry.

RESULTS

 The developed algorithm combines data from the three modalities. The ratio of the events within a kidney-VOI and the events from the summed coronary SPECT views (kidney ROI) represents the contribution of the kidney to the whole-body kidney ROI. This fraction was calculated to 49 % (17 % - 78 %) and 45 % (18 % - 75 %) for the left and the right kidney, respectively. Quantification of activity was deduced from equalizing the WBS count with the concurrent gamma probe measurement. Monoexponential curves were fitted to the obtained kidney activities, with resulting doses of 0,13 to 0,77 Gy/GBq (average 0,36 and 0,39 Gy/GBq for the left and the right kidney).

CONCLUSION

 The presented method is suitable to perform kidney dosimetry by using a gamma probe and a gamma camera, without using SPECT/CT.

In vivo confirmation of altered hepatic glucose metabolism in patients with liver fibrosis/cirrhosis by 18F-FDG PET/CT

OBJECTIVE

The aim of this study was to assess the value of ¹⁸F-FDG PET/CT for quantitative assessment of hepatic metabolism in patients with different stages of liver fibrosis/cirrhosis.

MATERIALS AND METHODS

¹⁸F-FDG PET/CT scans of 37 patients either with or without liver fibrosis/cirrhosis, classified according to the METAVIR score (F0-F4) obtained from histopathological analysis of liver specimen, were analyzed retrospectively and classified as follows: no liver fibrosis (F0, n = 6), mild liver fibrosis (F1, n = 11), advanced liver fibrosis (F2, n = 6), severe liver fibrosis (F3, n = 5), and liver cirrhosis (F4, n = 11). The liver-to-blood ratio (LBR, scan time corrected for a reference time of 75 min) was compared between patient groups.

RESULTS

Patients with liver fibrosis or cirrhosis (≥ F1; LBR 1.53 ± 0.35) showed a significant higher LBR than patients with normal liver parenchyma (F0, 1.08 ± 0.23; P = 0.004). In direct comparison, LBR increased up to the advanced stage of liver fibrosis (F2; 2.00 ± 0.40) and decreased until liver cirrhosis is reached (F4, 1.32 ± 0.14).

CONCLUSION

Functional changes in liver parenchyma during liver fibrosis/cirrhosis affect hepatic glucose metabolism and significantly differ between stages of liver fibrosis/cirrhosis, classified according to the METAVIR scoring system, as demonstrated by LBR quantification by ¹⁸F-FDG PET/CT.

Fluorescence-guidance in non-Gadolinium enhancing, but FET-PET positive gliomas

OBJECTIVES

We report on five patients with gadolinium-negative (non-enhancing magnetic resonance imaging-MRI) but ¹⁸F-fluoroethyl tyrosine positron-emission tomography (FET-PET) positive glioma (NEG) undergoing surgery under fluorescence-guidance with fluorescein sodium 10% (FL, Alkon, Germany) in combination with a dedicated light filter (YELLOW 560 nm, Carl Zeiss Meditec, Germany).

PATIENTS AND METHOD

Since 2017, five patients (3 female, 2 male; mean age 45.4 years) underwent fluorescence-guided surgery for supratentorial, intracerebral lesions which showed no contrast-enhancement in the preoperative MRI but were, however, strongly suspicious for gliomas. Accordingly, all patients received a preoperative FET-PET scan and detailed histopathological workup was performed. After giving written informed consent, all patients received 5 mg/kg of FL at the induction of anesthesia. Surgery was conducted under white light and under the YELLOW 560 nm filter. We reviewed the surgical protocols, navigational storage and the image databases of our surgical microscopes for evidence of intraoperative fluorescence that corresponded to the FET-PET positive area.

RESULTS

In all patients we found distinct accordances between the FET-PET positive areas and the fluorescing regions within the targeted lesions. Histopathological workup of the fluorescent tissue revealed anaplastic oligodendroglioma, IDH-mutant and 1p/19-codeleted (WHO grade III) (n = 2), anaplastic astrocytoma, IDH-mutant (WHO grade III) (n = 1), oligodendroglioma, IDH-mutant and 1p/19q-codeleted (WHO grade II) (n = 1) and pilocytic astrocytoma (WHO grade I) (n = 1). No adverse events were noted.

DISCUSSION AND CONCLUSION

Despite the lack of gadolinium-enhancement in the preoperative MRI, all patients intravenously received FL to guide resection. Irrespective of the final grading, FL was extremely helpful in detecting the lesions and in identifying their border zones. In selected patients with NEG, but strong metabolic activity according to the FET-PET, FL may significantly increase the accuracy of surgery.

[Development of a national competency-based learning objective catalogue for undergraduate medical education in Germany]

AIMS

Implementation of the guidelines on the Competency-based Learning Objective Catalogue for Undergraduate Medical Education for a Nuclear Medicine curriculum on behalf of the committee on professional training and continuing education of the German Association of Nuclear Medicine (DGN) METHODS:: In 7 domains 100 learning objectives (LOs) were subject to a prioritization in 3 categories (A, B and C) by means of a questionnaire as part of a Delphi method, in collaboration with all members of the DGN holding a "venia legendi" as experts. Category A defined the essential LOs for each medical practitioner. The prioritization was made by ranking the frequency of the A-classifications. In the 2nd step of the Delphi method, a list of LOs with the ranking positions 1-5 in each domain was presented to the first round's experts as a core curriculum, asking either for acceptance or modifications.

RESULTS

The results of the 1st step of the Delphi method deliver a return rate of 29% of the questionnaires (55 out of 184). The 2nd round shows a return rate of 30.9% (57 out of 184) and full approval of the proposed LOs in all LO domains by in median 72 % of the experts consulted (61%-81%). The present final version contains 37 competency-based LOs in the LO domains "legal basis and radiation protection", "basic science", indications and contra-indications for "PET/CT", "scintigraphy and SPECT", "patient preparation", "image interpretation" as well as "therapy".

CONCLUSION

The Competency-based Learning Objective Catalogue for Nuclear Medicine describes the knowledge and competencies, every physician should have at the end of his medical studies. The LO catalogue is a living document, which needs to be adapted continuously to the progress of the medical and technological development.

Fluorescence-guidance in non-Gadolinium enhancing, but FET-PET positive gliomas

OBJECTIVES

We report on five patients with gadolinium-negative (non-enhancing magnetic resonance imaging-MRI) but ¹⁸F-fluoroethyl tyrosine positron-emission tomography (FET-PET) positive glioma (NEG) undergoing surgery under fluorescence-guidance with fluorescein sodium 10% (FL, Alkon, Germany) in combination with a dedicated light filter (YELLOW 560 nm, Carl Zeiss Meditec, Germany).

PATIENTS AND METHOD

Since 2017, five patients (3 female, 2 male; mean age 45.4 years) underwent fluorescence-guided surgery for supratentorial, intracerebral lesions which showed no contrast-enhancement in the preoperative MRI but were, however, strongly suspicious for gliomas. Accordingly, all patients received a preoperative FET-PET scan and detailed histopathological workup was performed. After giving written informed consent, all patients received 5 mg/kg of FL at the induction of anesthesia. Surgery was conducted under white light and under the YELLOW 560 nm filter. We reviewed the surgical protocols, navigational storage and the image databases of our surgical microscopes for evidence of intraoperative fluorescence that corresponded to the FET-PET positive area.

RESULTS

In all patients we found distinct accordances between the FET-PET positive areas and the fluorescing regions within the targeted lesions. Histopathological workup of the fluorescent tissue revealed anaplastic oligodendroglioma, IDH-mutant and 1p/19-codeleted (WHO grade III) (n = 2), anaplastic astrocytoma, IDH-mutant (WHO grade III) (n = 1), oligodendroglioma, IDH-mutant and 1p/19q-codeleted (WHO grade II) (n = 1) and pilocytic astrocytoma (WHO grade I) (n = 1). No adverse events were noted.

DISCUSSION AND CONCLUSION

Despite the lack of gadolinium-enhancement in the preoperative MRI, all patients intravenously received FL to guide resection. Irrespective of the final grading, FL was extremely helpful in detecting the lesions and in identifying their border zones. In selected patients with NEG, but strong metabolic activity according to the FET-PET, FL may significantly increase the accuracy of surgery.

Isolated metastasis of an EGFR-L858R-mutated NSCLC of the meninges: the potential impact of CXCL12/CXCR4 axis in EGFRmut NSCLC in diagnosis, follow-up and treatment

Brain and leptomeningeal metastasis (LMM) of non-small cell lung cancer is still associated with poor prognosis. Moreover, the current diagnostic standard for LMM often yields false negative results and the scientific progress in this field is still unsatisfying. We present a case of a 71-year old patient with an isolated LMM. While standard diagnostics could only diagnose a cancer of unknown primary, the use of [⁶⁸Ga]-Pentixafor-PET/CT (CXCR4-PET/CT, a radiotracer targeting CXCR4) and a liquid biopsy of the cerebrospinal fluid revealed the primary NSCLC. The detection of L858R-EGFR, a common driver mutation in NSCLC, enabled us to treat the patient with Afatinib and monitor treatment using [⁶⁸Ga]-Pentixafor PET/CT. To estimate the impact of CXCR4 signaling and its ligands in NSCLC brain metastasis we looked at their expression and correlation with EGFR mutations in a primary and brain metastasis data set and investigated the previously described binding of extracellular ubiquitin to CXCR4. In conclusion, we describe a novel approach to improve diagnostics towards LMM and underline the impact of the CXCL12/CXCR4 axis in brain metastasis in a subset of NSCLC patients. We cannot confirm a correlation of CXCR4 expression with EGFR mutations or the binding of extracellular ubiquitin as previously reported.

Einfluß morphologischer Veränderungen auf Durchblutung und Stoffwechsel bei zerebraler Mikroangiopathie

51 Patienten mit zerebraler Mikroangiopathie wurden mittels Kernspintomographie, 18FDG-PET und 99mTc-HMPAO-SPECT untersucht. Die genaue Zuordnung funktioneller zu den morphologischen Befunden wurde durch ein spezielles Kopf-halterungssystem für PET, SPECT- und KST-Untersuchungen hergestellt. Patienten mit weniger als vier lakunären Infarkten (LI) und ohne bis geringfügigen Deep White Matter Lesions (DWML) im KST wiesen keine signifikant veränderten Werte für rMRGIu und rCBF in grauer oder weißer Substanz auf im Vergleich zu Patienten mit vier oder mehr LI und ausgedehnten DWML. Eine semiquantitative Einteilung der Atrophie (A: keine bis geringfügige; B: mäßige bis schwere) erbrachte für B) im Vergleich zu A) signifikant erniedrigte rCBF- und rMRGIu-Werte in grauer und weißer Substanz. Somit sind bei Patienten mit ZMA nur die Hirnatrophie, jedoch nicht die charakteristischen LI und DWML mit einer meßbaren Erniedrigung von rCBF und rMRGIu korreliert.

A Method of Correlating and Merging Cerebral Morphology and Function by a Special Head Holder

Ein spezielles Kopfhalterungssystem wird als Voraussetzung zur Erzeugung und korrelativen Verarbeitung topographisch identischer morphologischer und funktioneller Bilddaten vorgestellt. Es ist an die verschiedenen Modalitäten (MRI, PET, SPECT) adaptierbar und basiert auf einer kommerziellen thermoplastischen Kopfmaske. Eine erwärmte flexible Form dieses Thermoplasts wird dazu verwendet, eine individuelle Kopfmaske für alle Modalitäten zu formen. Damit wird eine Fixierung des Patienten während der Messungen gewährleistet. Diese Methode garantiert auch eine exakte Repositionierung und damit gleiche Schnittorientierung der rekonstruierten Bilder. Durch Fusion der Hirnaußenkonturen oder der korrespondierenden Tomogramme MRI vs. PET oder MRI vs. SPECT wurde die Genauigkeit getestet: Sie betrug transaxial: <2,0 mm und axial: <3,0 mm bei Patientenstudien mit MRI-Schichtdicke von 6,0 mm.

Vergleich der Befunde von 18-FDG- PET und CT beim prätherapeutischen Staging maligner Lymphome

Ziel: Vergleich der diagnostischen Aussagekraft von FDG-PET und CT zum Staging vor Therapie unter Berücksichtigung von Lokalisation, Durchmesser und Histologie der Läsion sowie Erfassung des FDG-Uptakes. Methoden: CT- und FDG-PET-Untersuchungen bei 27 Patienten mit histologisch gesichertem malignen Lymphom als Erstmanifestation oder Rezidiv wurden retrospektiv und unabhängig voneinander ausgewertet. CT-positive nodale Läsionen waren im Querdurchmesser (DCT) >15 mm. Bei visueller Auswertung in iterativ rekonstruierten PET-Studien gefundene fokale, unphysiologische FDG-Speicherungen wurden positiv gewertet und hinsichtlich Läsionsgröße (DPET) und partial-volumenkorrigierten standardisierten Uptake-Werten (SUV) quantifiziert. Eine Unterteilung der Läsionen erfolgte nach Histologie und Qualität (abgrenzbarer Lymphknoten, Konglomerattumor, extranodale Läsion). Ergebnis: CT beschrieb bei 26 Patienten 78 Läsionen, alle auch durch PET bestätigt. PET lokalisierte darüber hinaus weitere 18 Läsionen (+23%), bei hochmalignen Non-Hodgkin-Lymphomen (NHL) sogar +25%. Im Bereich des Halses sowie bei Lungenläsionen waren die Verfahren gleichwertig, bei der Beurteilung der übrigen Lymphknotenregionen sowie von Leber und Milz wies PET mehr Läsionen nach. Der SUV war bei hochmalignen NHL (19,0) signifikant höher als bei niedrigmalignen NHL und M. Hodgkin (10,6 bzw. 11,1). DCT und DPET korrelierten bei abgrenzbaren Lymphknoten signifikant (r = 0,75). Schlußfolgerung: FDG-PET ist der CT im Staging maligner Lymphome vor Therapie ebenbürtig bis überlegen. Hierzu ist eine qualitative Befundung ausreichend. Die zusätzliche quantitative Auswertung kann bei NHL einen Hinweis auf den Malignitätsgrad geben.

One-year Follow-up of Neuropsychology, MRI, rCBF and Glucose Metabolism (rMRGlu) in Cerebral Microangiopathy

Background: MRI shows lacunar infarctions (LI), deep white matter lesions (DWML) and atrophy in cerebral microangiopathy, which is said to lead to vascular dementia. In a first trial series on 57 patients with confirmed pure cerebral microangiopathy (without concomitant macroangiopathy), neuropsychological impairment and (where present) brain atrophy correlated with decreased rCBF and rMRGlu. LI and DWML did not correlate with either neuropsychological impairment or decreased rCBF/rMRGIu. This study was done one year later to detect changes in any of the study parameters. Methods: 26 patients were re-examined for rCBF, rMRGlu, LI, DWML, atrophy and neuropsychological performance (7 cognitive, 3 mnestic, 4 attentiveness tests). Using a special head holder for exact repositioning, rCBF (SPECT) and rMRGlu (PET) were measured and imaged slice by slice. White matter/cortex were quantified using MRI-defined ROIs. Results: After one year the patients did not show significant decreases in rCBF or rMRGlu either in cortex or in white matter (p >0.05), nor did any patient show LI, DWML or atrophy changes on MRI. There were no significant neuropsychological decreases (p >0.05). Conclusions: Cerebral microangiopathy ought to show progressive neuropsychological, functional (rCBF, rMRGlu) and morphological deterioration over periods >1 year. It is unlikely that direct cortical damage (e.g., incomplete infarction) is responsible for neuropsychological impairment since one-year follow-up of our patients revealed no progression of brain atrophy or any other cortical damage.

Skelettdiagnostik mittels 18F-Natriumfluorid-PET und -PET/CT

In nuclear medicine, bone scanning is based on the principle of scintigraphy using boneseeking radiopharmaceuticals which accumulate in sites of increased bone formation. From a historical point of view, 18F-fluoride was one of the first osteotropic tracers which was replaced by 99mTc-labelled polyphosphonates. With the development of modern PET equipment the superior diagnostic performance of 18F-fluoride PET for the detection and characterization of osseous lesions was proven in comparison to conventional bone scanning. Recently, its importance as a substitute of conventional skeletal scintigraphy increased in a time with limited availability of 99Mo/ 99mTc. To ensure health care during this period, 18F-fluoride PET currently became part of common outpatient care.

This guideline comprehends recommendations on indications, protocols, interpretation and reporting of 18F-fluoride PET and PET/CT.

FDG-PET, PET/CT and conventional nuclear medicine procedures in the evaluation of lung cancer

Aim: Currently, the German and Austrian S3 guidelines on the evaluation and treatment of lung cancer are about to be published whereas the American Colleague of Chest Physicians (ACCP) guidelines were already presented in 2007. An important part of the diagnostic workup of lung cancer will be the evaluation of indeterminate lung lesions and the mediastinal and extrathoracic staging using FDG-PET or PET/CT. The results from the literature on FDG-PET and PET/ CT as well as on conventional nuclear medicine staging procedures and the clinical implications are presented. Methods: The literature data was amassed in analogy to the metaanalyses drawn for the current ACCP guidelines. In addition, relevant more recent publications were also considered. To answer the important question for the extent of pathological confirmation needed, the residual risk of mediastinal metastases was calculated for certain constellations of FDG-PET and CT findings. Suggested recommendations were characterized with the level of evidence. Results: FDG-PET (PET/CT) allows the differentiation of indeterminate lung lesions with high accuracy. FDG-PET (PET/ CT) is the most accurate non-invasive procedure to assess the mediastinal nodal stage, for non-small cell as well as for small cell lung cancer. It is justified to omit invasive evaluation of enlarged but FDG-PET negative lymph nodes under certain circumstances. Unexpected extrathoracic metastases detected by FDG-PET imply important changes in therapeutic management. Conclusion: The upcoming S3 guideline on lung cancer will recommend FDG-PET in several indications due to its clinical efficacy well proven by data from literature (high level of evidence). The selected use of conventional nuclear medicine procedures remains beyond doubt. FDG-PET (PET/CT) belongs to the standard of care in lung cancer.

PET with 18F-fluorodeoxyglucose for staging of non-small cell lung cancer

Aims: To evaluate studies on the use of positron emission tomography with the glucose analog 18F-fluorodeoxyglucose (FDG-PET) for the preoperative staging of patients with non-small cell lung cancer (NSCLC) according to the criteria of evidence based medicine and to discuss the cost-effectiveness of the technique. Methods: Clinical studies published between 1995 and 2002 on the preoperative staging of non-small cell lung cancer were used for this analysis. Studies that did not meet the criteria published by the European Agency for the Evaluation of Medicinal Products (EMEA) were excluded. The validity of the studies was evaluated by a standardized rating system developed by the Agency for Health Care Policy and Research (AHCPR). Results: For the detection of mediastinal lymph node metastases the mean sensitivity and specificity of FDG-PET on a patient basis is 85% and 87% (16 studies, 1355 patients). In studies that compared FDG-PET and computed tomography (CT) the mean sensitivity of CT was 66% at a specificity of 71%. In the detection of distant metastases FDG-PET correctly changed the tumor stage in 18% of the patients when compared to CT based staging (10 studies, 1073 patients). Five cost effectiveness analyses from the USA, Japan, and Germany concluded that FDG-PET improves the outcome of treatment at reduced or only slightly increased overall costs. Improvement of patient outcome was also demonstrated in a randomized trial, which found that the risk of a futile thoracotomy was reduced by 51% (p = 0.003) when FDG-PET was added to the preoperative staging. Conclusion: According to the criteria of the AHCPR the use of FDG-PET for detection of mediastinal lymph node and distant metastases is documented at a level of evidence Ia and Ib, respectively. Since systematic analyses also indicate a favorable cost-effectiveness ratio FDG-PET has to be considered as ”strictly indicated“ for the preoperative staging of non-small cell lung cancer.

Para-[123I]iodo-L-phenylalanine in patients with pancreatic adenocarcinoma

Recently, p-[123I]iodo-L-phenylalanine (IPA) was clinically validated for brain tumour imaging. Preclinical studies demonstrated uptake of IPA into pancreatic adenocarcinoma suggesting its diagnostic application in patients with pancreatic tumours. The aim was to study the tumour uptake of IPA in patients with pancreatic adenocarcinoma and to analyse its biodistribution and dosimetry to assess the radiation dose resulting from its diagnostic use. Patients, methods: Seven patients with pancreatic adenocarcinoma underwent whole-body scintigraphies and SPECT up to 24 h after administration of 250 MBq of IPA. Tumour uptake of IPA was assessed visually. Time activity curves and the corresponding residence times were determined for whole-body, kidneys, liver, spleen, lung, heart content, brain, and testes. Mean absorbed doses for various organs and the effective dose were assessed based on the MIRD formalism using OLINDA/EXM. Results: IPA exhibited no accumulation in proven manifestations of pancreatic adenocarcinomas. IPA was exclusively eliminated by the urine and showed a delayed clearance from blood. Residence times were 0.26 ± 0.09 h for kidneys, 0.38 ± 0.19 h for liver, 0.15 ± 0.07 h for spleen, 0.51 ± 0.20 h for lungs, 0.22 ± 0.07 h for heart content, 0.11 ± 0.05 h for brain, 0.014 ± 0.005 h for testes and 6.4 ± 2.2 h for the remainder. The highest absorbed doses were determined in the urinary bladder wall and in the kidneys. According to the ICRP 60 the effective dose resulting from 250 MBq IPA was 3.6 ± 0.7 mSv. Conclusion: Para-[123I]iodo-L-phenylalanine can be used in diagnostic nuclear medicine with acceptable radiation doses. Besides its proven validity for brain tumour imaging, IPA does not appear to be suitable as tracer for pancreatic cancer.

Nuklearmedizin in Deutschland

Aim: To explain the spectrum and number of in-vivo nuclear medicine examinations and therapies based on official statistics about out-patient and in-patient care. Trends in time of the frequency and spectrum of procedures as well as data on the health care structure for nuclear medicine in Germany should be collected. Methods: Data from the Gesundheitsberichterstattung des Bundes, from the frequency statistics of the statutory health insurance for out-patients and from the Bundes - ärztekammer were used. Customized queries were performed to analyse temporal changes. Results: Nuclear medicine physicians are more frequently consulted by out-patients over the last years (2008: 2 024 498; 2009: 2 164 664) and the number of colleagues in private practice increased. For in-patients, the frequency of conventional nuclear medicine procedures (mainly for brain, lymphatic system, lung and heart) increased since 2008 after a decline in previous years (2009: 323 515; +4.6%) and the number of PET(/CT) examinations continued to rise (2009: 25 123; +18%), even if changes in OPS keys may hamper comparisons. Nearly 600 gamma cameras and 76 PET(/CT) scanners were installed in hospitals in 2008. Nuclear medicine procedures are increasingly performed as cross sectional imaging like SPECT(/CT) and PET(/CT). With the supply shortfall with 99Mo, the frequency of thyroid scans with 123I iodine increased as well as the use of 18F PET as a substitute for conventional bone scans. The number of radionuclide therapies, in particular non-thyroid treatments, increased since the mid-nineties and stabilized at nearly 50 000 cases per year with shorter lengths of stay. Conclusion: The details of the present analysis may help to understand the positive evolution of key numbers for nuclear medicine.

Effect of lifelong antibiotic treatment for aortic arch prosthesis infection

A patient who underwent multiple aortic operations suffered persistent infection of the ascending aorta and arch prosthesis and was finally treated with lifelong antibiotics. An 8-year follow-up with positron emission computed tomography is reported.

Radiotherapy to bulky disease PET-negative after immunochemotherapy in elderly DLBCL patients: Results of a planned interim analysis of the first 187 patients with bulky disease treated in the OPTIMAL>60 study of the DSHNHL

7506

Background: RT to bulky sites improves outcome of elderly DLBCL patients [Lancet Oncol 2008; 9: 105-116; J Clin Oncol 2014; 32:112-1118]. Whether RT can be spared in PET-negative pts. after R-CHOP was prospectively addressed in OPTIMAL >60. Methods: 61 to 80 y-old pts. were randomized in a 2x2 factorial design to 6xCHOP-14 or 6xCHLIP-14 (liposomal instead of conventional vincristine) plus 8 x rituximab 375 mg/m2(R) q 2 wks. or 12xR (days -4,-1,1,4,14,28,42,56,91,126,175, 238). Pts. with bulk (>=7.5 cm) PET-positive after 6 cycles chemotherapy were assigned to RT (39.6 Gy), while PET-negative bulks were observed. Results: 187/505 (37%) had bulky disease and were compared to 117/306 (38%) RICOVER-60 pts. (38%) who had received 6xCHOP-14+8R. OPTIMAL>60 pts. were older (70 vs. 68 years) and had more IPI=3 (33% vs. 29%) and IPI=4,5 (34% vs. 23%) compared to RICOVER-60. PET was performed in 166/187 OPTIMAL>60 bulk pts. (reasons for no PET: early death: 5; excessive toxicity: 3; protocol violation: 1, non-compliance: 4, change of diagnosis: 6, others: 2). 80/166 (48%) bulks remained PET-positive after 6 cycles of chemotherapy and 62/80 (78%) were irradiated (reasons for no RT: progression: 8; medical reasons: 9; negative biopsy: 1), reducing RT from 67/117 (57%) in RICOVER-60 by 42% to 62/187 (33%) in OPTIMAL>60. Despite the unfavorable demographics, outcome of the 187 bulk pts. in OPTIMAL>60 was non-inferior to RICOVER-60, not even in the least intensive of the 4 OPTIMAL>60 treatment arms consisting of 47 pts. who received 6xCHOP-14+8R as in RICOVER-60. 2-year PFS and OS in OPTIMAL>60 was 79% and 88%, respectively, compared to 75% and 78% of the 117 RICOVER-60 pts. In a multivariable analysis adjusting for the IPI risk factors, the hazard ratio of the OPTIMAL>60 compared to the RICOVER-60 bulk pts. was 0.7 (95% CI: 03.; 1.5; p=0.345) for PFS and 0.5 (95% CI: 02.; 1.3; p=0.154) for OS. Conclusions: RT can be spared in bulky disease PET-negative after chemotherapy. This strategy results in a 42% reduction of RT without compromising the outcome of these patients. Supported by Amgen, Roche, Spectrum. Clinical trial information: NCT01478542.

[Nuclear Medicine in Germany. Updated key data and trends from official statistics]

AIM

Updated presentation of the spectrum of nuclear medicine in-vivo examinations and therapies from officially available statistics on out-patient and in-patient care as well as trends of structural data on nuclear medicine in Germany.

METHODS

Data from the German Federal Health Monitoring, from the frequency statistics of the statutory health insurance for out-patients and from the German Medical Association were used and supplemented by data from selective literature searches.

RESULTS

In descending order, thyroid, bone and cardiac scans continue to be the most frequent nuclear medicine procedures. With a marked increase of PET/CT and SPECT/CT, the number of basic scintigraphies is declining. Cardiac, lung and brain scans as well as lymph scintigraphies are increasingly requested, bone and thyroid scan decrease. The consultation of nuclear medicine physicians in private practices is increasing by 4 % per year (2009: 2 164 664; 2015: 2 687 359). The number of nuclear medicine physicians in the out-patient sector rose significantly (2009: 756, 2015: 939, growth 24 %) and has remained constant due to restrictions since 2013. The specialist recognitions of women in nuclear medicine increased (proportion currently 46 %). In hospitals, more PET(/CT) scanners (2009: 97; 2015: 125) and fewer gamma cameras (2009: 594; 2015: 550) are operated. The number of non-thyroid (and also out-patient) radionuclide therapies continued to increase.

CONCLUSION

With increased use of hybrid technologies, the nuclear medicine spectrum shows positive trends especially in nuclear cardiology and extra-thyroid therapy. These developments must be taken into account when amending regulations of specialist training and medical student teaching.

Epileptic Activity Increases Cerebral Amino Acid Transport Assessed by 18F-Fluoroethyl-l-Tyrosine Amino Acid PET: A Potential Brain Tumor Mimic

O-(2-¹⁸F-fluoroethyl)-l-tyrosine (¹⁸F-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect ¹⁸F-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by ¹⁸F-FET PET and to elucidate the pathophysiologic background.

METHODS

Ten patients with 11 episodes of serial seizures or status epilepticus, who underwent MRI and ¹⁸F-FET PET, were studied. The main diagnosis was glioma World Health Organization grade II-IV (n = 8); 2 patients suffered from nonneoplastic diseases. Immunohistochemical assessment of LAT1/LAT2/CD98 amino acid transporters was performed in seizure-affected cortex (n = 2) and compared with glioma tissues (n = 3).

RESULTS

All patients exhibited increased seizure-associated strict gyral ¹⁸F-FET uptake, which was reversible in follow-up studies or negative shortly before and without any histologic or clinical signs of tumor recurrence. ¹⁸F-FET uptake corresponded to structural MRI changes, compatible with cortical vasogenic and cytotoxic edema, partial contrast enhancement, and hyperperfusion. Patients with prolonged postictal symptoms lasting up to 8 wk displayed intensive and widespread (≥ 1 lobe) cortical ¹⁸F-FET uptake. LAT1/LAT2/CD98 was strongly expressed in neurons and endothelium of seizure-affected brains and less in reactive astrocytosis.

CONCLUSION

Seizure activity, in particular status epilepticus, increases cerebral amino acid transport with a strict gyral ¹⁸F-FET uptake pattern. Such periictal pseudoprogression represents a potential pitfall of ¹⁸F-FET PET and may mimic brain tumor. Our data also indicate a seizure-induced upregulation of neuronal, endothelial, and less astroglial LAT1/LAT2/CD98 amino acid transporter expression.

Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19)  GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100  TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.

Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube: IceCube Collaboration

We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.

[Positron emission tomography 2013 in Germany. Results of the query and current status]

AIM

Five years after the first survey the positron emission tomography (PET) council of the German Society of Nuclear Medicine (DGN) repeated a survey to re-evaluate the status of PET diagnostics in Germany based on the data of the year 2013.

METHODS

A web-based questionnaire was used for gathering information retrospectively. Details regarding the physicians involved in PET operations, PET systems, and radiopharmaceuticals were also part of the survey as well as indications and number of studies. Furthermore, the role of PET and PET/CT within the diagnostic process was evaluated. In addition, official statistical hospital reports were analysed.

RESULTS

Responses from 52 sites were analysed. They reported a total of 38,350 PET studies in 2013. In the majority of cases PET was used in oncologic indications (87%). Further main applications were: neurology 6%, cardiology 1%, and inflammation 5%. University or other hospitals performed 85% of the studies. The portion of in-patients was 26%. Hybrid systems (56 PET/CT, 5 PET/MRT, and 2 stand-alone PET) were most frequently used for imaging. The radiotracers were labelled with F-18 in 90% of the studies, whereas Ga-68 was used in 9% and C-11 in 1%. Lung tumours were the most investigated tumour entity (40%), followed by malignant lymphoma (8%), tumours of the gastrointestinal tract (5%), and NET (5%). 20% of the 333 physicians hold a PET certificate awarded by the DGN. More than 50% of the facilities were certified according ISO9001, KTQ or QEP standard. The findings of nearly 60% of the oncological studies were discussed interdisciplinary in a tumour board. In federal statistical reports a 56% increase of in-patient PET operations during 5 years was found.

CONCLUSION

In Germany, a moderate increase (9% per year) of PET studies is observed, but compared with other industrialised countries PET is still less established.