The presence of prostate MRI-visible lesions at follow-up biopsy as a risk factor for histopathological upgrading during active surveillance.

Objective: To prospectively determine the ability of visible lesions on multiparametric MRI (PI-RADS 4-5) and commonly used biomarkers to predict disease upgrading on rebiopsy in men with low-risk prostate cancer (PCa) enrolled in active surveillance (AS).

Materials And Methods: For this prospective study, approved by the Institutional Review Board (IRB), we selected consecutive patients with low-risk, low-grade, and localized prostate cancer (PCa) from our active surveillance (AS) program, who were enrolled between March 2014 and December 2020. Patients who had undergone previous prostate surgery, hormonal treatment, had contraindications for mpMRI, or transrectal ultrasound-guided (TRUS) biopsy were excluded from this study.

Exacerbated Renal and Hematologic Toxicities to Ifosfamide and Doxorubicin-Based Chemotherapy in a Patient with Retroperitoneal Liposarcoma Harboring a Germline Mutation in the WRN Gene.

Werner's syndrome is caused by the inactivation of both WRN alleles and is characterized by premature aging and increased risk of neoplasms, especially those of mesenchymal origins, such as sarcomas. Given the characteristic genomic instability, patients with this syndrome are more susceptible to develop toxicities when exposed to cytotoxic agents, such as alkylators and anthracyclines. The impact of the monoallelic WRN mutation on treatment-associated toxicities is poorly understood.

Value of Primary Rectal Tumor PET/MRI in the Prediction of Synchronic Metastatic Disease.

Purpose: To analyze the associations between positron emission tomography (PET)/magnetic resonance imaging (MRI) features for primary rectal tumors and metastases.

Procedures: Between November 2016 and April 2018, 101 patients with rectal adenocarcinoma were included in this prospective study (NCT02537340) for whole-body PET/MRI for baseline staging. Two readers analyzed the PET/MRI; they assessed the semiquantitative PET features of the primary tumor and the N- and M-stages.

PET/MRI Characterization of Mucinous Versus Nonmucinous Components of Rectal Adenocarcinoma: A Comparison of Tumor Metabolism and Cellularity.

The purpose of this study was to evaluate whether FDG PET/MRI can be used to differentiate the mucinous from the nonmucinous components of primary rectal tumors and to compare the glycolytic metabolism on PET with tumor cellularity on DWI in both components. Ninety-nine patients who underwent FDG PET/MRI for staging of primary rectal cancer were included in this prospective analysis. MRI depicted the mucin component through the tumor volume.

Reassessing Patterns of Response to Immunotherapy with PET: From Morphology to Metabolism.

Cancer demands precise evaluation and accurate and timely assessment of response to treatment. Imaging must be performed early during therapy to allow adjustments to the course of treatment. For decades, cross-sectional imaging provided these answers, showing responses to the treatment through changes in tumor size.

Theranostics in Nuclear Medicine: Emerging and Re-emerging Integrated Imaging and Therapies in the Era of Precision Oncology.

Theranostics refers to the pairing of diagnostic biomarkers with therapeutic agents that share a specific target in diseased cells or tissues. Nuclear medicine, particularly with regard to applications in oncology, is currently one of the greatest components of the theranostic concept in clinical and research scenarios. Theranostics in nuclear medicine, or nuclear theranostics, refers to the use of radioactive compounds to image biologic phenomena by means of expression of specific disease targets such as cell surface receptors or membrane transporters, and then to use specifically designed agents to deliver ionizing radiation to the tissues that express these targets.

Prostate-specific Membrane Antigen PET: Therapy Response Assessment in Metastatic Prostate Cancer.

Therapy response assessment is a critical step in cancer management, leading clinicians to optimize the use of therapeutic options during the course of the disease. Imaging is a pivotal biomarker for therapy response evaluation in oncology and has gained wider use through the development of reproducible data-based guidelines, of which the Response Evaluation Criteria in Solid Tumors is the most successful example. Disease-specific criteria have also been proposed, and the Prostate Cancer Working Group 3 criteria are the mainstay for prostate cancer (PC).

Diagnostic accuracy of FDG-PET/MRI versus pelvic MRI and thoracic and abdominal CT for detecting synchronous distant metastases in rectal cancer patients.

Purpose: We compared the diagnostic accuracy of detecting distant metastases for baseline rectal cancer staging between PET/MRI and conventional staging (CS).

Materials And Methods: This prospective study from November 2016 to April 2018 included 101 rectal adenocarcinoma patients for primary staging. These patients underwent whole-body PET/MRI in addition to CS (pelvic MRI and thoracic and abdominal contrast-enhanced CT).

Nonprostatic diseases on PSMA PET imaging: a spectrum of benign and malignant findings.

PSMA PET imaging was originally used to assess biochemical recurrence of prostate cancer (PCa), but its clinical use was promptly extended to detection, staging and therapy response assessment. The expanding use of PSMA PET worldwide has also revealed PSMA ligand uptake in diverse nonprostatic diseases, which raised questions about the specificity of this imaging modality. Although not very common initially, a growing number of pathologies presenting PSMA uptake on PET have been reported in the last few years, and a proper interpretation of PSMA PET imaging findings suddenly became challenging and, to some extent, confusing.

Regorafenib in Patients with Antiangiogenic-Naïve and Chemotherapy-Refractory Advanced Colorectal Cancer: Results from a Phase IIb Trial.

Background: Regorafenib is a multikinase inhibitor with antiangiogenic effects that improves overall survival (OS) in metastatic colorectal cancer (mCRC) after failure of standard therapies. We investigated the efficacy and safety of regorafenib in antiangiogenic therapy-naïve chemotherapy-refractory advanced colorectal cancer.

Patients And Methods: This single-center, single-arm, phase IIb study (NCT02465502) enrolled adults with mCRC whose disease had progressed on, or who were intolerant to, standard therapy, but who were antiangiogenic therapy-naïve.

Aberrant Hypermetabolism of Benign Uterine Leiomyoma on 18F-FDG PET/CT.

Leiomyomas are prevalent benign smooth muscle tumors in the uterus, displaying variable degrees of FDG uptake on PET/CT. The glucose metabolism intensity of those lesions relies on biologic features and markedly increased FDG accumulation is more typically related to malignant diseases, as in the case of leiomyosarcomas. Notwithstanding that uterine fibroids typically exhibit mild to moderate FDG uptake, in this article we report a case of unexpectedly intense hypermetabolism of a benign uterine leiomyoma on a PET/CT scan performed for initial staging of a breast cancer patient.

Revisiting Prostate Cancer Recurrence with PSMA PET: Atlas of Typical and Atypical Patterns of Spread.

The introduction of prostate-specific membrane antigen (PSMA) in clinical practice has revolutionized evaluation of biochemical recurrence of prostate cancer after curative-intent treatment. The high expression of this glycoprotein in prostate cancer cells makes PSMA imaging superior to the current conventional staging methods, namely bone scanning and CT. The high capability of PSMA imaging for identifying very small previously undetected lesions has been widely demonstrated in the literature, leading to a rethinking of patient management by oncologists, urologists, and radiation oncologists.

Positron emission tomography/magnetic resonance imaging (PET/MRI): An update and initial experience at HC-FMUSP.

The new technology of PET/MRI is a prototype of hybrid imaging, allowing for the combination of molecular data from PET scanning and morphofunctional information derived from MRI scanning. Recent advances regarding the technical aspects of this device, especially after the development of MRI-compatible silicon photomultipliers of PET, permitted an increase in the diagnostic performance of PET/MRI translated into dose reduction and higher imaging quality. Among several clinical applications, PET/MRI gains ground initially in oncology, where MRI per se plays an essential role in the assessment of primary tumors (which is limited in the case of PET/CT), including prostate, rectal and gynecological tumors.

Clinical evaluation of a block sequential regularized expectation maximization reconstruction algorithm in 18F-FDG PET/CT studies.

Purpose: To investigate the clinical performance of a block sequential regularized expectation maximization (BSREM) penalized likelihood reconstruction algorithm in oncologic PET/computed tomography (CT) studies.

Methods: A total of 410 reconstructions of 41 fluorine-18 fluorodeoxyglucose-PET/CT studies of 41 patients with a total of 2010 lesions were analyzed by two experienced nuclear medicine physicians. Images were reconstructed with BSREM (with four different β values) or ordered subset expectation maximization (OSEM) algorithm with/without time-of-flight (TOF/non-TOF) corrections.

Estimating (131)I biokinetics and radiation doses to the red marrow and whole body in thyroid cancer patients: probe detection versus image quantification.

Objective: To compare the probe detection method with the image quantification method when estimating (131)I biokinetics and radiation doses to the red marrow and whole body in the treatment of thyroid cancer patients.

Materials And Methods: Fourteen patients with metastatic thyroid cancer, without metastatic bone involvement, were submitted to therapy planning in order to tailor the therapeutic amount of (131)I to each individual. Whole-body scans and probe measurements were performed at 4, 24, 48, 72, and 96 h after (131)I administration in order to estimate the effective half-life (Teff) and residence time of (131)I in the body.

18F-FDG PET/CT Osteometabolic Activity in Metastatic Parathyroid Carcinoma.

Parathyroid cancer is an uncommon type of malignancy, which is frequently associated with poor prognosis. Clinical manifestations are caused by elevated serum calcium and parathyroid hormone (PTH). Diagnostic imaging studies as neck ultrasonography, technetium Tc Tc-sestamibi whole body scintigraphy, CT, and MR are already established tools for this malignancy.

Clinical Impact of 68Ga-PSMA PET/CT in a Patient With Biochemical Recurrence of Prostate Cancer.

A 64-year-old man with history of prostate adenocarcinoma underwent radical prostatectomy in 2003. He remained with undetectable prostate-specific antigen (PSA) levels until 2014, when he then presented rising serum PSA levels and performed a Tc-MDP bone scan that was negative for metastases. In August 2015, his PSA was 4.

Clinical image quality perception and its relation to NECR measurements in PET.

Background: The purpose of this study is to describe a clinical relation of noise equivalent count rate (NECR) - an objective measurement of positron emission tomography (PET) systems - measured in a large number of patients, to clinical image quality of PET and their relation to 18F-fluoro-2-deoxyglucose (FDG) activity and patient's weight.

Methods: A total of 71 consecutive patients were evaluated in this retrospective study. All data was automatically analysed using Matlab to estimate the noise equivalent count rate.

18F-FDG-PET/MR increases diagnostic confidence in detection of bone metastases compared with 18F-FDG-PET/CT.

Purpose: The aim of this study was to compare detection, lesion conspicuity and reader confidence of F-fluorodeoxyglucose (F-FDG)-PET/MR and F-FDG-PET/computed tomography (CT) in patients with F-FDG avid bone metastases.

Materials And Methods: In this prospective study, a total of 30 PET/CT and PET/MRI data sets were performed in 24 patients. Each examination was evaluated for the presence of PET-positive bone lesions consistent with metastatic involvement.

Dose Optimization in TOF-PET/MR Compared to TOF-PET/CT.

Purpose: To evaluate the possible activity reduction in FDG-imaging in a Time-of-Flight (TOF) PET/MR, based on cross-evaluation of patient-based NECR (noise equivalent count rate) measurements in PET/CT, cross referencing with phantom-based NECR curves as well as initial evaluation of TOF-PET/MR with reduced activity.

Materials And Methods: A total of 75 consecutive patients were evaluated in this study. PET/CT imaging was performed on a PET/CT (time-of-flight (TOF) Discovery D 690 PET/CT).

PET/MRI and PET/CT in advanced gynaecological tumours: initial experience and comparison.

Purpose: To compare the diagnostic accuracy of PET/MRI and PET/CT for staging and re-staging advanced gynaecological cancer patients as well as identify the potential benefits of each method in such a population.

Material And Methods: Twenty-six patients with suspicious or proven advanced gynaecological cancer (12 ovarian, seven cervical, one vulvar and four endometrial tumours, one uterine metastasis, and one primary peritoneal cancer) underwent whole-body imaging with a sequential trimodality PET/CT/MR system. Images were analysed regarding primary tumour detection and delineation, loco-regional lymph node staging, and abdominal/extra-abdominal distant metastasis detection (last only by PET/CT).