Showing papers in "European Journal of Nuclear Medicine and Molecular Imaging in 2015"

FDG PET/CT: EANM procedure guidelines for tumour imaging: version 2.0

Abstract: The purpose of these guidelines is to assist physicians in recommending, performing, interpreting and reporting the results of FDG PET/CT for oncological imaging of adult patients. PET is a quantitative imaging technique and therefore requires a common quality control (QC)/quality assurance (QA) procedure to maintain the accuracy and precision of quantitation. Repeatability and reproducibility are two essential requirements for any quantitative measurement and/or imaging biomarker. Repeatability relates to the uncertainty in obtaining the same result in the same patient when he or she is examined more than once on the same system. However, imaging biomarkers should also have adequate reproducibility, i.e. the ability to yield the same result in the same patient when that patient is examined on different systems and at different imaging sites. Adequate repeatability and reproducibility are essential for the clinical management of patients and the use of FDG PET/CT within multicentre trials. A common standardised imaging procedure will help promote the appropriate use of FDG PET/CT imaging and increase the value of publications and, therefore, their contribution to evidence-based medicine. Moreover, consistency in numerical values between platforms and institutes that acquire the data will potentially enhance the role of semiquantitative and quantitative image interpretation. Precision and accuracy are additionally important as FDG PET/CT is used to evaluate tumour response as well as for diagnosis, prognosis and staging. Therefore both the previous and these new guidelines specifically aim to achieve standardised uptake value harmonisation in multicentre settings.

The diagnostic value of PET/CT imaging with the 68Ga-labelled PSMA ligand HBED-CC in the diagnosis of recurrent prostate cancer

Abstract: Purpose Since the introduction of positron emission tomography (PET) imaging with 68Ga-PSMA-HBED-CC (=68Ga-DKFZ-PSMA-11), this method has been regarded as a significant step forward in the diagnosis of recurrent prostate cancer (PCa). However, published data exist for small patient cohorts only. The aim of this evaluation was to analyse the diagnostic value of 68Ga-PSMA-ligand PET/CT in a large cohort and the influence of several possibly interacting variables.

Long-term tolerability of PRRT in 807 patients with neuroendocrine tumours: the value and limitations of clinical factors

Abstract: Peptide receptor radionuclide therapy (PRRT) with 90Y and 177Lu provides objective responses in neuroendocrine tumours, and is well tolerated with moderate toxicity. We aimed to identify clinical parameters predictive of long-term renal and haematological toxicity (myelodysplastic syndrome and acute leukaemia). Of 807 patients studied at IEO-Milan (1997–2013), 793 (98 %) received 177Lu (278, 34.4 %), 90Y (358, 44.4 %) or 177Lu and 90Y combined (157. 19.5 %), and 14 (2 %) received combinations of PRRT and other agents. Follow-up was 30 months (1–180 months). The parameters evaluated included renal risk factors, bone marrow toxicity and PRRT features. Data analysis included multiple regression, random forest feature selection, and recursive partitioning and regression trees. Treatment with 90Y and 90Y + 177Lu was more likely to result in nephrotoxicity than treatment with 177Lu alone (33.6 %, 25.5 % and 13.4 % of patients, respectively; p < 0.0001). Nephrotoxicity (any grade), transient and persistent, occurred in 279 patients (34.6 %) and was severe (grade 3 + 4) in 12 (1.5 %). In only 20–27 % of any nephrotoxicity was the disease modelled by risk factors and codependent associations (p < 0.0001). Hypertension and haemoglobin toxicity were the most relevant factors. Persistent toxicity occurred in 197 patients (24.3 %). In only 22–34 % of affected patients was the disease modelled by the clinical data (p < 0.0001). Hypertension (regression coefficient 0.14, p < 0.0001) and haemoglobin toxicity (regression coefficient 0.21, p < 0.0001) were pertinent factors. Persistent toxicity was associated with shorter PRRT duration from the first to the last cycle (mean 387 vs. 658 days, p < 0.004). Myelodysplastic syndrome occurred in 2.35 % of patients (modelled by the clinical data in 30 %, p < 0.0001). Platelet toxicity grade (2.05 ± 1.2 vs. 0.58 ± 0.8, p < 0.0001) and longer PRRT duration (22.6 ± 24 vs. 15.5 ± 9 months, p = 0.01) were relevant. Acute leukaemia occurred in 1.1 % of patients (modelled by the clinical data in 18 %, p < 0.0001). Identified risk factors provide a limited (<30 %) risk estimate even with target tissue dosimetry. These data strongly suggest the existence of unidentified individual susceptibilities to radiation-associated disease.

EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT: 2015 revision

Abstract: Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: http://eanm.org/publications/guidelines/2015_07_EANM_FINAL_myocardial_perfusion_guideline.pdf .

68 Ga-PSMA PET/CT for restaging recurrent prostate cancer: which factors are associated with PET/CT detection rate?

Abstract: Purpose To assess the association between PSA levels, PSA kinetics and other factors and a pathological 68Ga-PSMA PET/CT scan in patients with recurrent prostate cancer (rPCa) with biochemical relapse (BR) after radical therapy

Diagnosis of pseudoprogression in patients with glioblastoma using O-(2-[18F]fluoroethyl)-l-tyrosine PET

Abstract: The follow-up of glioblastoma patients after radiochemotherapy with conventional MRI can be difficult since reactive alterations to the blood–brain barrier with contrast enhancement may mimic tumour progression (i.e. pseudoprogression, PsP). The aim of this study was to assess the clinical value of O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) PET in the differentiation of PsP and early tumour progression (EP) after radiochemotherapy of glioblastoma. A group of 22 glioblastoma patients with new contrast-enhancing lesions or lesions showing increased enhancement (>25 %) on standard MRI within the first 12 weeks after completion of radiochemotherapy with concomitant temozolomide (median 7 weeks) were additionally examined using amino acid PET with 18F-FET. Maximum and mean tumour-to-brain ratios (TBRmax, TBRmean) were determined. 18F-FET uptake kinetic parameters (i.e. patterns of time–activity curves, TAC) were also evaluated. Classification as PsP or EP was based on the clinical course (no treatment change at least for 6 months), follow-up MR imaging and/or histopathological findings. Imaging results were also related to overall survival (OS). PsP was confirmed in 11 of the 22 patients. In patients with PsP, 18F-FET uptake was significantly lower than in patients with EP (TBRmax 1.9 ± 0.4 vs. 2.8 ± 0.5, TBRmean 1.8 ± 0.2 vs. 2.3 ± 0.3; both P < 0.001) and presence of MGMT promoter methylation was significantly more frequent (P = 0.05). Furthermore, a TAC type II or III was more frequently present in patients with EP (P = 0.04). Receiver operating characteristic analysis showed that the optimal 18F-FET TBRmax cut-off value for identifying PsP was 2.3 (sensitivity 100 %, specificity 91 %, accuracy 96 %, AUC 0.94 ± 0.06; P < 0.001). Univariate survival analysis showed that a TBRmax <2.3 predicted a significantly longer OS (median OS 23 vs. 12 months; P = 0.046). 18F-FET PET may facilitate the diagnosis of PsP following radiochemotherapy of glioblastoma.

Prognostic value of volumetric parameters of (18)F-FDG PET in non-small-cell lung cancer: a meta-analysis.

Abstract: Purpose We conducted a comprehensive systematic review of the literature on volumetric parameters from 18F-FDG PET and a meta-analysis of the prognostic value of metabolic tumour volume (MTV) and total lesion glycolysis (TLG) in patients with lung cancer.

[(68)Ga]PSMA-HBED uptake mimicking lymph node metastasis in coeliac ganglia: an important pitfall in clinical practice.

Abstract: To determine the frequency of seemingly pathological retroperitoneal uptake in the location of the coeliac ganglia in patients undergoing [68Ga]PSMA-HBED PET/CT. The study included 85 men with prostate cancer referred for [68Ga]PSMA-HBED PET/CT. The PET/CT scans were evaluated for the local finding in the prostate and the presence of lymph node metastases, distant metastases and coeliac ganglia. The corresponding standardized uptake values (SUV) were determined. SUVmax to background uptake (gluteal muscle SUVmean) ratios were calculated for the ganglia and lymph node metastases. Immunohistochemistry was performed on the ganglia. In 76 of the 85 patients (89.4 %) at least one ganglion with tracer uptake was found. For the ganglia, SUVmax and SUVmax to background SUVmean ratios were 2.97 ± 0.88 and 7.98 ± 2.84 (range 1.57–6.38 and 2.83–30.6), respectively, and 82.8 % of all ganglia showed an uptake ratio of >5.0. For lymph node metastases, SUVmax and SUVmax to background SUVmean ratios were 8.5 ± 7.0 and 23.31 ± 22.23 (range 2.06–35.9 and 5.25–115.8), respectively. In 35 patients (41.2 %), no lymph node metastases were found but tracer uptake was seen in the ganglia. Immunohistochemistry confirmed strong PSMA expression in the ganglia. Coeliac ganglia show a relevant [68Ga]PSMA-HBED uptake in most patients and may mimic lymph node metastases.

[177Lu]Lutetium-labelled PSMA ligand-induced remission in a patient with metastatic prostate cancer

Abstract: The prostate-specific membrane antigen (PSMA) shows intense overexpression in the majority of prostate cancers (PCa) [1]. A Glu-urea-Lys motif has been found to bind with high affinity to the catalytic domain of PSMA [2]. Following conjugation to the chelator HBED-CC, a Ga-labelled PSMA ligand (Ga-DKFZ-11) has been derived as a novel PET tracer [3]. Since PSMA is internalized after binding of a ligand [4], it is also an excellent target for systemic radionuclide therapy. Consequently, a I-labelled PSMA ligand (I-MIP-1095) demonstrated favourable tumour-targeting properties and promising antitumour efficacy [5]. However, clinical application of I causes a high radiation burden and is hampered by complex regulations in most countries. Therefore, Lu is considered to be preferable for targeted radionuclide therapy. The novel theranostic drug Lu-DKFZ-617 is a DOTA derivative of the Glu-urea-Lys motif. The chelator is conjugated via an aromatic linker that further improves tumour accumulation while simultaneously reducing kidney uptake. The image presented here shows a patient with metastatic PCa. PSMA PET/CT (a) demonstrates a tumour phenotype with strong PSMA expression. The patient was treated with a cumulative activity of 7.4 GBq Lu-DKFZ-617 (b, c). Restaging with PSMA PET/CT (d) reveals a striking radiological response. In addition the PSA level decreased from 38.0 to 4.6 ng/ml. Patient stratification by means of PSMA imaging and subsequent treatment with a therapeutic PSMA-targeted

Pre-therapeutic dosimetry of normal organs and tissues of (177)Lu-PSMA-617 prostate-specific membrane antigen (PSMA) inhibitor in patients with castration-resistant prostate cancer.

Abstract: 177Lu-617-prostate-specific membrane antigen (PSMA) ligand seems to be a promising tracer for radionuclide therapy of progressive prostate cancer. However, there are no published data regarding the radiation dose given to the normal tissues. The aim of the present study was to estimate the pretreatment radiation doses in patients who will undergo radiometabolic therapy using a tracer amount of 177Lu-labeled PSMA ligand. The study included seven patients with progressive prostate cancer with a mean age of 63.9 ± 3.9 years. All patients had prior PSMA positron emission tomography (PET) imaging and had intense tracer uptake at the lesions. The injected 177Lu-PSMA-617 activity ranged from 185 to 210 MBq with a mean of 192.6 ± 11.0 MBq. To evaluate bone marrow absorbed dose 2-cc blood samples were withdrawn in short variable times (3, 15, 30, 60, and 180 min and 24, 48, and 120 h) after injection. Whole-body images were obtained at 4, 24, 48, and 120 h post-injection (p.i.). The geometric mean of anterior and posterior counts was determined through region of interest (ROI) analysis. Attenuation correction was applied using PSMA PET/CT images. The OLINDA/EXM dosimetry program was used for curve fitting, residence time calculation, and absorbed dose calculations. The calculated radiation-absorbed doses for each organ showed substantial variation. The highest radiation estimated doses were calculated for parotid glands and kidneys. Calculated radiation-absorbed doses per megabecquerel were 1.17 ± 0.31 mGy for parotid glands and 0.88 ± 0.40 mGy for kidneys. The radiation dose given to the bone marrow was significantly lower than those of kidney and parotid glands (p < 0.05). The calculated radiation dose to bone marrow was 0.03 ± 0.01 mGy/MBq. Our first results suggested that 177Lu-PSMA-617 therapy seems to be a safe method. The dose-limiting organ seems to be the parotid glands rather than kidneys and bone marrow. The lesion radiation doses are within acceptable ranges; however, there is a substantial individual variance so patient dosimetry seems to be mandatory.

A multicentre comparison of quantitative 90Y PET/CT for dosimetric purposes after radioembolization with resin microspheres: the QUEST Phantom Study

Abstract: Purpose To investigate and compare the quantitative accuracy of 90Y imaging across different generation PET/CT scanners, for the purpose of dosimetry after radioembolization with resin microspheres.

Accuracy of F-DOPA PET and perfusion-MRI for differentiating radionecrotic from progressive brain metastases after radiosurgery

Abstract: We assessed the performance of 6-[18F]-fluoro-l-3,4-dihydroxyphenylalanine (F-DOPA) PET for differentiating radionecrosis (RN) from tumour progression (PD) in a population of patients with brain metastases, treated with stereotactic radiosurgery. The accuracy of F-DOPA PET was compared with that of perfusion-weighted magnetic resonance (perfusion-MR). In 42 patients with a total of 50 brain metastases from various primaries F-DOPA PET/CT was performed because of suspected radiological progression at the site of previously irradiated brain metastasis. Several semiquantitative PET parameters were recorded, and their diagnostic accuracy was compared by receiver operating characteristic curve analyses. The diagnosis was established by either surgery or follow-up. A comparison was made between F-DOPA PET and perfusion-MR sequences acquired no more than 3 weeks apart. Definitive outcome was available in 46 of the 50 lesions (20 PD, 26 RN). Of the 46 lesions, 11 were surgically excised while in the remaining 35 lesions the diagnosis was established by radiological and clinical criteria. The best diagnostic performance was obtained using the semiquantitative PET parameter maximum lesion to maximum background uptake ratio (SUVLmax/Bkgrmax). With a cut-off value of 1.59, a sensitivity of 90 % and a specificity of 92.3 % were achieved in differentiating RN from PD lesions (accuracy 91.3 %). Relative cerebral blood volume (rCBV) derived from perfusion-MR was available for comparison in 37 of the 46 metastases. Overall accuracy of rCBV was lower than that of all semiquantitative PET parameters under study. The best differentiating rCBV cut-off value was 2.14; this yielded a sensitivity of 86.7 % and a specificity of 68.2 % (accuracy 75.6 %). F-DOPA PET is a highly accurate tool for differentiating RN from PD brain metastases after stereotactic radiosurgery. In this specific setting, F-DOPA PET seems to perform better than perfusion-MR.

Radioembolization of hepatocarcinoma with 90 Y glass microspheres: development of an individualized treatment planning strategy based on dosimetry and radiobiology

Abstract: The aim of this study was to optimize the dosimetric approach and to review the absorbed doses delivered, taking into account radiobiology, in order to identify the optimal methodology for an individualized treatment planning strategy based on 99mTc-macroaggregated albumin (MAA) single photon emission computed tomography (SPECT) images. We performed retrospective dosimetry of the standard TheraSphere® treatment on 52 intermediate (n = 17) and advanced (i.e. portal vein thrombosis, n = 35) hepatocarcinoma patients with tumour burden 10 cc). Apparent radiosensitivity values from TCP were around 0.003/Gy, a factor of 3–5 lower than in EBRT, as found by other authors. The dose-rate effect was negligible: a purely linear model can be applied. Toxicity incidence was significantly larger for Child B7 patients (89 vs 14 %, p < 0.0001), who were therefore excluded from dose-toxicity analysis. Child A toxic vs non-toxic treatments were significantly separated in terms of dose averaged on whole non-tumoural parenchyma (including non-irradiated regions) with AUC from 0.73 to 0.94. TD50 was ≈ 100 Gy. No methodology was superior to parenchyma mean dose, which therefore can be used for planning, with a limit of TD15 ≈ 75 Gy. A dosimetric treatment planning criterion for Child A patients without complete obstruction of the portal vein was developed.

Predictive value of early 18F-FDG PET/CT studies for treatment response evaluation to ipilimumab in metastatic melanoma: preliminary results of an ongoing study

Abstract: Purpose Ipilimumab is a newly approved immunotherapeutic agent that has been shown to provide a survival benefit in patients with metastatic melanoma. 18F-FDG PET/CT has demonstrated very satisfying results in detecting melanoma metastases in general. Using 18F-FDG PET/CT we monitored patients with metastatic melanoma undergoing ipilimumab therapy during the course of treatment. The aim of our study was to evaluate the role of 18F-FDG PET/CT performed after two cycles of ipilimumab in predicting the final response to therapy.

(18)F-NaF PET/CT: EANM procedure guidelines for bone imaging

Abstract: The aim of this guideline is to provide minimum standards for the performance and interpretation of (18)F-NaF PET/CT scans. Standard acquisition and interpretation of nuclear imaging modalities will help to provide consistent data acquisition and numeric values between different platforms and institutes and to promote the use of PET/CT modality as an established diagnostic modality in routine clinical practice. This will also improve the value of scientific work and its contribution to evidence-based medicine.

Diagnostic accuracy and impact on management of 18 F-FDG PET and PET/CT in colorectal liver metastasis: a meta-analysis and systematic review

Abstract: The first aim of the review (aim 1) was to obtain the diagnostic performance values of 18F-FDG PET for the detection and staging of liver metastases in patients with colorectal cancer (CRC), the second aim (aim 2) was to compare PET and conventional imaging modalities, and the third aim (aim 3) was to evaluate the impact of PET on patient management. The incidence of extrahepatic disease (EHD) detected by PET is also reviewed. A comprehensive search was performed on PubMed/MEDLINE for studies evaluating PET and PET/CT in CRC patients with liver metastases up to June 2014. For inclusion PET had to have been performed prior to surgery, there had to be at least 18 patients in the study, and the reported data had to allow calculation of 2 × 2 contingency tables (for aim 1). A total of 18 studies were eligible for at least one of the three intended subanalyses including a total of 1,059 patients. Pooled sensitivity, specificity and accuracy and the corresponding 95 % confidence intervals were derived from the contingency tables on a patient basis (patient-based analysis, PBA) and a lesion basis (lesion-based analysis, LBA) for eight studies. Pooled sensitivity and specificity of PET on PBA were both 93 %. Corresponding values for LBA were 60 % and 79 %, respectively. Areas under the summary ROC were 0.97 for PBA and 0.67 for LBA. Regarding aim 2, PET had a slightly lower sensitivity than MRI and CT on PBA (93 %, 100 % and 98 %, respectively) and LBA (66 %, 89 % and 79 %, respectively) but appeared to be more specific than MRI and CT (86 %, 81 % and 67 %, respectively). PET findings resulted in changes in the management of a mean of 24 % of patients. The mean incidence of PET-based EHD was 32 %. This meta-analysis suggests that FDG PET/CT is highly accurate for the detection of liver metastases on a patient basis but less accurate on a lesion basis. Compared to MRI, PET is less sensitive but more specific and affects the management of about one-quarter of patients.

[18F]THK-5117 PET for assessing neurofibrillary pathology in Alzheimer’s disease

Abstract: Visualization of the spatial distribution of neurofibrillary tangles would help in the diagnosis, prevention and treatment of dementia. The purpose of the study was to evaluate the clinical utility of [18F]THK-5117 as a highly selective tau imaging radiotracer. We initially evaluated in vitro binding of [3H]THK-5117 in post-mortem brain tissues from patients with Alzheimer’s disease (AD). In clinical PET studies, [18F]THK-5117 retention in eight patients with AD was compared with that in six healthy elderly controls. Ten subjects underwent an additional [11C]PiB PET scan within 2 weeks. In post-mortem brain samples, THK-5117 bound selectively to neurofibrillary deposits, which differed from the binding target of PiB. In clinical PET studies, [18F]THK-5117 binding in the temporal lobe clearly distinguished patients with AD from healthy elderly subjects. Compared with [11C]PiB, [18F]THK-5117 retention was higher in the medial temporal cortex. These findings suggest that [18F]THK-5117 provides regional information on neurofibrillary pathology in living subjects.

18F-GE-180: a novel TSPO radiotracer compared to 11C-R-PK11195 in a preclinical model of stroke

Abstract: Neuroinflammation plays a critical role in various neuropathological conditions, and hence there is renewed interest in the translocator protein (TSPO) as a biomarker of microglial activation and macrophage infiltration in the brain. This is reflected in the large amount of research conducted seeking to replace the prototypical PET radiotracer 11C-R-PK11195 with a TSPO ligand with higher performance. Here we report the in vivo preclinical investigation of the novel TSPO tracer 18F-GE-180 in a rat model of stroke. Focal cerebral ischaemia was induced in Wistar rats by 60-min occlusion of the middle cerebral artery (MCAO). Brain damage was assessed 24 h after MCAO by T2 MRI. Rats were scanned with 11C-R-PK11195 and 18F-GE-180 5 or 6 days after MCAO. Specificity of binding was confirmed by injection of unlabelled R-PK11195 or GE-180 20 min after injection of 18F-GE-180. In vivo data were confirmed by ex vivo immunohistochemistry for microglial (CD11b) and astrocytic biomarkers (GFAP). 18F-GE-180 uptake was 24 % higher in the core of the ischaemic lesion and 18 % lower in the contralateral healthy tissue than that of 11C-R-PK11195 uptake (1.5 ± 0.2-fold higher signal to noise ratio). We confirmed this finding using the simplified reference tissue model (BPND = 3.5 ± 0.4 and 2.4 ± 0.5 for 18F-GE-180 and 11C-R-PK11195, respectively, with R 1 = 1). Injection of unlabelled R-PK11195 or GE-180 20 min after injection of 18F-GE-180 significantly displaced 18F-GE-180 (69 ± 5 % and 63 ± 4 %, respectively). Specificity of the binding was also confirmed by in vitro autoradiography, and the location and presence of activated microglia and infiltrated macrophages were confirmed by immunohistochemistry. The in vivo binding characteristics of 18F-GE-180 demonstrate a better signal to noise ratio than 11C-R-PK11195 due to both a better signal in the lesion and lower nonspecific binding in healthy tissue. These results provide evidence that 18F-GE-180 is a strong candidate to replace 11C-R-PK11195.

First evidence of PSMA expression in differentiated thyroid cancer using [⁶⁸Ga]PSMA-HBED-CC PET/CT.

Abstract: The prostate-specific membrane antigen (PSMA) has recently emerged as a target for radionuclide imaging and therapy of prostate cancer [1, 2]. However, PSMA expression was also shown on the cell membrane of endothelial cells of tumour neovasculature in a number of other cancers such as renal cell carcinoma [3, 4], colon carcinoma, neuroendocrine tumours, melanoma or breast cancer [3]. However, to our knowledge no study has yet investigated

PSMA PET/CT with Glu-urea-Lys-(Ahx)-[68Ga(HBED-CC)] versus 3D CT volumetric lymph node assessment in recurrent prostate cancer

Abstract: Purpose PET/CT with the PSMA ligand is a powerful new method for the early detection of nodal metastases in patients with biochemical relapse. The purpose of this retrospective investigation was to evaluate the volume and dimensions of nodes identified by Glu-urea-Lys-(Ahx)-[68Ga(HBED-CC)] (68Ga-PSMA-11) in the setting of recurrent prostate cancer.

Astrocytosis precedes amyloid plaque deposition in Alzheimer APPswe transgenic mouse brain: a correlative positron emission tomography and in vitro imaging study

Abstract: Purpose Pathological studies suggest that neuroinflammation is exacerbated by increased beta-amyloid (Aβ) levels in the brain early in Alzheimer’s disease (AD). The time course and relationships between astrocytosis and Aβ deposition were examined using multitracer in vivo positron emission tomography (PET) imaging in an AD transgenic mouse model, followed by postmortem autoradiography and immunohistochemistry analysis.

Zone-size nonuniformity of 18F-FDG PET regional textural features predicts survival in patients with oropharyngeal cancer

Abstract: Purpose The question as to whether the regional textural features extracted from PET images predict prognosis in oropharyngeal squamous cell carcinoma (OPSCC) remains open. In this study, we investigated the prognostic impact of regional heterogeneity in patients with T3/T4 OPSCC.

EANM practice guidelines for lymphoscintigraphy and sentinel lymph node biopsy in melanoma

Abstract: Sentinel lymph node biopsy is an essential staging tool in patients with clinically localized melanoma. The harvesting of a sentinel lymph node entails a sequence of procedures with participation of specialists in nuclear medicine, radiology, surgery and pathology. The aim of this document is to provide guidelines for nuclear medicine physicians performing lymphoscintigraphy for sentinel lymph node detection in patients with melanoma. These practice guidelines were written and have been approved by the European Association of Nuclear Medicine (EANM) to promote high-quality lymphoscintigraphy. The final result has been discussed by distinguished experts from the EANM Oncology Committee, national nuclear medicine societies, the European Society of Surgical Oncology (ESSO) and the European Association for Research and Treatment of Cancer (EORTC) melanoma group. The document has been endorsed by the Society of Nuclear Medicine and Molecular Imaging (SNMMI). The present practice guidelines will help nuclear medicine practitioners play their essential role in providing high-quality lymphatic mapping for the care of melanoma patients.

[(18)F]FDG PET/MRI vs. PET/CT for whole-body staging in patients with recurrent malignancies of the female pelvis: initial results.

Abstract: To evaluate the diagnostic potential of PET/MRI with [18F]FDG in recurrent ovarian and cervical cancer in comparison to PET/CT. A group of 19 patients with suspected recurrence of pelvic malignancies (ovarian cancer, 11 patients; cervical cancer, 8 patients) scheduled for an [18F]FDG PET/CT were subsequently enrolled for a PET/MRI. The scan protocol comprised: (1) a T1-W axial VIBE after contrast agent adminstration, (2) an axial T2-W HASTE, (3) a coronal TIRM, (4) an axial DWI, and dedicated MR sequences of the female pelvis including (5) a T1-W VIBE before contrast agent adminstration, (6) a sagittal T2-W TSE, and (7) a sagittal T1-W dynamic VIBE. The datasets (PET/CT, PET/MRI) were rated separately by two readers regarding lesion count, lesion localization, lesion conspicuity (four-point scale), lesion characterization (benign/malignant/indeterminate) and diagnostic confidence (three-point scale). All available data (histology, prior examinations, PET/CT, PET/MRI, follow-up examinations) served as standard of reference. Median values were compared using the Wilcoxon rank sum test. Metastatic lesions were present in 16 of the 19 patients. A total of 78 lesions (malignant, 58; benign, 20) were described. Both PET/CT and PET/MRI allowed correct identification of all malignant lesions and provided equivalent conspicuity (3.86 ± 0.35 for PET/CT, 3.91 ± 0.28 for PET/MRI; p > 0.05). Diagnostic confidence was significantly higher for PET/MRI in malignant (p < 0.01) and benign lesions (p < 0.05). Both PET/CT and PET/MRI offer an equivalently high diagnostic value for recurrent pelvic malignancies. PET/MRI offers higher diagnostic confidence in the discrimination of benign and malignant lesions. Considering the reduced radiation dose and superior lesion discrimination, PET/MRI may serve as a powerful alternative to PET/CT in the future.

Cortical hypermetabolism in MCI subjects: a compensatory mechanism?

Abstract: Purpose Alzheimer’s disease (AD) is associated with amyloid accumulation that takes place decades before symptoms appear. Cognitive impairment in AD is associated with reduced glucose metabolism. However, neuronal plasticity/compensatory mechanisms might come into play before the onset of dementia. The aim of this study was to determine whether there is evidence of cortical hypermetabolism as a compensatory mechanism before amyloid deposition takes place in subjects with amnestic mild cognitive impairment (aMCI).

[89Zr]Oxinate4 for long-term in vivo cell tracking by positron emission tomography

Abstract: Purpose 111In (typically as [111In]oxinate3) is a gold standard radiolabel for cell tracking in humans by scintigraphy. A long half-life positron-emitting radiolabel to serve the same purpose using positron emission tomography (PET) has long been sought. We aimed to develop an 89Zr PET tracer for cell labelling and compare it with [111In]oxinate3 single photon emission computed tomography (SPECT).

Imaging large vessel vasculitis with fully integrated PET/MRI: a pilot study

Abstract: The aim of this study was to evaluate the feasibility of hybrid [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/MRI in patients with large vessel vasculitis (LVV) by comparing visual and quantitative parameters to that of PET/CT. Furthermore, the value of PET/MRI in disease activity and extent of LVV was assessed. A total of 16 [18F]FDG PET/MRI and 12 [18F]-FDG PET/CT examinations were performed in 12 patients with LVV. MRI of the vessel wall by T1-weighted and T2-weighted sequences was used for anatomical localization of FDG uptake and identification of morphological changes associated with LVV. In addition, contrast-enhanced (CE) magnetic resonance angiography (MRA) was performed. The vascular FDG uptake in the vasculitis group was compared to a reference group of 16 patients using a four-point visual score. Visual scores and quantitative parameters [maximum standardized uptake value (SUVmax) and target to background ratio (TBR)] were compared between PET/MRI and PET/CT. Furthermore, correlations between C-reactive protein (CRP) and quantitative PET results, as well the extent of vasculitis in PET, MRI/CE-MRA and combined PET/MRI, were analysed. TBRs, SUVmax values and visual scores correlated well between PET/MRI and PET/CT (r = 0.92, r = 0.91; r = 0.84, p < 0.05). There was no significant difference between both modalities concerning SUVmax measurements and visual scores. In PET/MRI, PET alone revealed abnormal FDG uptake in 86 vascular regions. MRI/CE-MRA indicated 49 vessel segments with morphological changes related to vasculitis, leading to a total number of 95 vasculitis regions in combination with PET. Strong and significant correlations between CRP and disease extent in PET alone (r = 0.75, p = 0.0067) and PET/MRI (r = 0.92, p < 0.0001) in contrast to MRI/CE-MRA only were observed. Regarding disease activity, no significant correlations were seen between quantitative PET results and CRP, although there was a trend towards significance (r = 0.55, p = 0.0651). PET/MRI also showed active LVV in 15/16 examinations. Hybrid PET/MRI is feasible in LVV and holds promise for precisely determining disease extent and disease activity.

Harmonizing FDG PET quantification while maintaining optimal lesion detection: prospective multicentre validation in 517 oncology patients.

Abstract: Purpose Point-spread function (PSF) or PSF + time-of-flight (TOF) reconstruction may improve lesion detection in oncologic PET, but can alter quantitation resulting in variable standardized uptake values (SUVs) between different PET systems. This study aims to validate a proprietary software tool (EQ.PET) to harmonize SUVs across different PET systems independent of the reconstruction algorithm used.

Renal function affects absorbed dose to the kidneys and haematological toxicity during 177Lu-DOTATATE treatment

Abstract: Purpose Peptide receptor radionuclide therapy (PRRT) has become an important treatment option in the management of advanced neuroendocrine tumours. Long-lasting responses are reported for a majority of treated patients, with good tolerability and a favourable impact on quality of life. The treatment is usually limited by the cumulative absorbed dose to the kidneys, where the radiopharmaceutical is reabsorbed and retained, or by evident haematological toxicity. The aim of this study was to evaluate how renal function affects (1) absorbed dose to the kidneys, and (2) the development of haematological toxicity during PRRT treatment.

Favourable outcomes of (177)Lu-octreotate peptide receptor chemoradionuclide therapy in patients with FDG-avid neuroendocrine tumours.

Abstract: Increased glycolytic activity on FDG PET/CT defines a subgroup of patients with metastatic gastroenteropancreatic neuroendocrine tumour (NET) with a poor prognosis. A limited range of systemic treatment options exist for more aggressive NET. The role of peptide receptor chemoradionuclide therapy (PRCRT) in such patients is, however, unclear. This retrospective study assessed the outcomes of patients with FDG-avid NET treated with PRCRT. Clinical, biochemical and imaging response was assessed after completion of induction treatment of PRCRT with 5-fluorouracil in 52 patients selected for treatment on the basis of somatostatin-receptor imaging without spatially discordant FDG-avid disease. Of the cohort, 67 % had received prior chemotherapy. Overall survival (OS) and progression-free survival (PFS) were also analysed. PRCRT was well tolerated with negligible grade 3/4 toxicities. After a median follow-up period of 36 months, the median OS was not achieved with a median PFS of 48 months. At 3 months after completion of PRCRT 2 % of patients showed a complete anatomical response, 28 % a partial response, 68 % stable disease, and only 2 % progression. On FDG PET/CT, 27 % achieved a complete metabolic response during the follow-up period. A biochemical response (>25 % fall in chromogranin-A levels) was seen in 45 %. PRCRT is an effective treatment in patients with FDG-avid NET, even in patients who have failed conventional therapies. Given apparently higher response rates than with alternative therapeutic options and low toxicity, further research is needed to establish whether PRCRT should be used as a first-line treatment modality in this patient population.