Quantification of [Tc]Tc-HDP bone SPECT/CT: can we improve the body weight based standardized uptake value with a more robust normalization?

Background: The introduction of quantitative SPECT/CT allows more objective assessments of tracer accumulation in SPECT. However standardized uptake values (SUV) still do not play a big role for orthopedic or oncologic questions. With a more reliable normalization, the use of quantitative measures might also be of use for a more objective assessment of lesions.

Immunohistochemical ERG positivity is associated with decreased PSMA expression and lower visibility in corresponding [Ga]Ga-PSMA-11 PET scans of primary prostate cancer.

Purpose: TMPRSS2:ERG gene fusion negatively regulates PSMA expression in prostate adenocarcinoma (PCa) cell lines. Therefore, immunohistochemical (IHC) ERG expression, a surrogate for an underlying ERG rearrangement, and PSMA expression patterns in radical prostatectomy (RPE) specimens of primary PCa, including corresponding PSMA-PET scans were investigated.

Methods: Two cohorts of RPE samples (total n=148): In cohort #1 (n=62 patients) with available RPE and preoperative [Ga]Ga-PSMA-11 PET, WHO/ISUP grade groups, IHC-ERG (positive vs.

Beyond Prostate Imaging Reporting and Data System: Combining Magnetic Resonance Imaging Prostate Imaging Reporting and Data System and Prostate-Specific Membrane Antigen-Positron Emission Tomography/Computed Tomography PRIMARY Score in a Composite (P) Score for More Accurate Diagnosis of Clinically Significant Prostate Cancer.

Purpose: The Prostate Imaging Reporting and Data System (PI-RADS) score is standard of care for clinically significant prostate cancer (csPCa) diagnosis. The PRIMARY score (prostate-specific membrane antigen [PSMA]-positron emission tomography [PET]/CT) also has high diagnostic accuracy for csPCa. This study aimed to develop an easily calculated combined (P) score for csPCa detection (International Society of Urological Pathology [ISUP] ≥2) incorporating separately read PI-RADS and PRIMARY scores, with external validation.

PSMA-positive prostatic volume prediction with deep learning based on T2-weighted MRI.

Purpose: High PSMA expression might be correlated with structural characteristics such as growth patterns on histopathology, not recognized by the human eye on MRI images. Deep structural image analysis might be able to detect such differences and therefore predict if a lesion would be PSMA positive. Therefore, we aimed to train a neural network based on PSMA PET/MRI scans to predict increased prostatic PSMA uptake based on the axial T2-weighted sequence alone.

Evaluating the biodistribution for [Ga]Ga-PSMA-11 and [F]F-PSMA-1007 PET/CT with an inter- and intrapatient based analysis.

Background: Liver uptake in [Ga]Ga-PSMA-11 PET is used as an internal reference in addition to clinical parameters to select patients for [Lu]Lu-PSMA-617 radioligand therapy (RLT). Due to increased demand, [Ga]Ga-PSMA-11 was replaced by [F]F-PSMA-1007, a more lipophilic tracer with different biodistribution and splenic uptake was suggested as a new internal reference. We compared the intra-patient tracer distribution between [Ga]Ga-PSMA-11 and [F]F-PSMA-1007.

Relaxed fibronectin: a potential novel target for imaging endometriotic lesions.

Background: Endometriosis is characterized by the ectopic occurrence of endometrial tissue. Though considered benign, endometriotic lesions possess tumor-like properties such as tissue invasion and remodeling of the extracellular matrix. One major clinical hurdle concerning endometriosis is its diagnosis.

Reproducibility and Accuracy of the PRIMARY Score on PSMA PET and of PI-RADS on Multiparametric MRI for Prostate Cancer Diagnosis Within a Real-World Database.

The PRIMARY score is a 5-category scale developed to identify clinically significant intraprostate malignancy (csPCa) on Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT (Ga-PSMA PET) using a combination of anatomic site, pattern, and intensity. Developed within the PRIMARY trial, the score requires evaluation in external datasets. This study aimed to assess the reproducibility and diagnostic accuracy of the PRIMARY score in a cohort of patients who underwent multiparametric MRI (mpMRI) and Ga-PSMA PET before prostate biopsy for the diagnosis of prostate cancer.

Can We Predict Skeletal Lesion on Bone Scan Based on Quantitative PSMA PET/CT Features?

Objective: The increasing use of PSMA-PET/CT for restaging prostate cancer (PCa) leads to a patient shift from a non-metastatic situation based on conventional imaging (CI) to a metastatic situation. Since established therapeutic pathways have been designed according to CI, it is unclear how this should be translated to the PSMA-PET/CT results. This study aimed to investigate whether PSMA-PET/CT and clinical parameters could predict the visibility of PSMA-positive lesions on a bone scan (BS).

A third of the radiotracer dose: two decades of progress in pediatric [F]fluorodeoxyglucose PET/CT and PET/MR imaging.

Objectives: To assess the evolution of administered radiotracer activity for F-18-fluorodeoxyglucose (18F-FDG) PET/CT or PET/MR in pediatric patients (0-16 years) between years 2000 and 2021.

Methods: Pediatric patients (≤ 16 years) referred for 18F-FDG PET/CT or PET/MR imaging of the body during 2000 and 2021 were retrospectively included. The amount of administered radiotracer activity in megabecquerel (MBq) was recorded, and signal-to-noise ratio (SNR) was measured in the right liver lobe with a 4 cm volume of interest as an indicator for objective image quality.

Whole-Body 18 F-FDG PET/CT Patlak Parametric Imaging of Hepatic Alveolar Echinococcosis.

We present dynamic 18 F-FDG PET/CT acquisition in a 52-year-old old woman with histologically proven hepatic alveolar echinococcosis (AE). Metabolic rate of FDG images generated with traditional and relative Patlak analysis show the AE manifestation in the liver significantly better the static SUV images. Dynamic PET may thus have the potential to increase sensitivity in the assessment of hepatic AE manifestations.

Can PSMA PET/CT help in dose-tailoring in post-prostatectomy radiotherapy?

There are few randomized trials to evaluate the use of PSMA-PET in the planning of post-prostatectomy radiotherapy. There are two unresolved questions 1) should we increase the dose to lesions visible on PSMA-PET 2) can we reduce dose in the case of a negative PSMA-PET. In this review, we summarize and discuss the available evidence in the literature.

European Association of Nuclear Medicine Focus 5: Consensus on Molecular Imaging and Theranostics in Prostate Cancer.

Background: In prostate cancer (PCa), questions remain on indications for prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging and PSMA radioligand therapy, integration of advanced imaging in nomogram-based decision-making, dosimetry, and development of new theranostic applications.

Objective: We aimed to critically review developments in molecular hybrid imaging and systemic radioligand therapy, to reach a multidisciplinary consensus on the current state of the art in PCa.

Design, Setting, And Participants: The results of a systematic literature search informed a two-round Delphi process with a panel of 28 PCa experts in medical or radiation oncology, urology, radiology, medical physics, and nuclear medicine.

Fully automated computational measurement of noise in positron emission tomography.

Objectives: To introduce an automated computational algorithm that estimates the global noise level across the whole imaging volume of PET datasets.

Methods: [F]FDG PET images of 38 patients were reconstructed with simulated decreasing acquisition times (15-120 s) resulting in increasing noise levels, and with block sequential regularized expectation maximization with beta values of 450 and 600 (Q.Clear 450 and 600).

Is There a Role of Interim PSMA PET in Chemotherapy of Prostate Cancer?

While RECIST 1.1 is well established in radiological response assessment, it is of limited use in prostate cancer (PCa) considering that the disease is often seen only as sclerotic bone changes on conventional imaging. Therefore, a molecular imaging-based response assessment including bone scans has been proposed and used in clinical trials, however, due to the flare phenomenon on bone scans this assessment leads to substantial delays in the detection of progression.

Interdisciplinary Swiss consensus recommendations on staging and treatment of advanced prostate cancer.

The management of prostate cancer is undergoing rapid changes in all disease settings. Novel imaging tools for diagnosis have been introduced, and the treatment of high-risk localized, locally advanced and metastatic disease has changed considerably in recent years. From clinical and health-economic perspectives, a rational and optimal use of the available options is of the utmost importance.

Improved Prostate-Specific Membrane Antigen (PSMA) Stimulation Using a Super Additive Effect of Dutasteride and Lovastatin In Vitro.

Prostate-specific membrane antigen (PSMA)-based imaging improved the detection of primary, recurrent and metastatic prostate cancer. However, in certain patients, a low PSMA surface expression can be a limitation for this promising diagnostic tool. Pharmacological induction of PSMA might be useful to further improve the detection rate of PSMA-based imaging.

Development and external validation of a multivariable [Ga]Ga-PSMA-11 PET-based prediction model for lymph node involvement in men with intermediate or high-risk prostate cancer.

Purpose: To develop and evaluate a lymph node invasion (LNI) prediction model for men staged with [Ga]Ga-PSMA-11 PET.

Methods: A consecutive sample of intermediate to high-risk prostate cancer (PCa) patients undergoing [Ga]Ga-PSMA-11 PET, extended pelvic lymph node dissection (ePLND), and radical prostatectomy (RP) at two tertiary referral centers were retrospectively identified. The training cohort comprised 173 patients (treated between 2013 and 2017), the validation cohort 90 patients (treated between 2016 and 2019).