Background
The rapidly expanding clinical adaptation of prostate-specific membrane antigen (PSMA)-targeted PET imaging in the evaluation of patients with prostate cancer has placed an increasing onus ...on understanding both the potential pearls of interpretation as well as limitations of this new technique. As with any new molecular imaging modality, accurate characterization of abnormalities on PSMA-targeted PET imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants of radiotracer uptake, and potential sources of false-positive and false-negative imaging findings. In recent years, a growing number of reports have come to light describing incidental non-prostatic benign or malignant pathologies with high uptake on PSMA-targeted PET imaging. In this review, we have summarized the published literature regarding the potential pearls and technical and interpretive pitfalls of this imaging modality. Knowledge of these limitations can increase the confidence of interpreting physicians and thus improve patient care.
Conclusions
As PSMA-targeted PET is expected to be evaluated in larger prospective trials, the dissemination of potential diagnostic pitfalls and the biologic underpinning of those findings will be of increased importance.
The purpose of this article is to summarize the evidence regarding the role of FDG PET/CT in treatment response assessment and surveillance of lung cancer and to provide suggested best practices.
FDG ...PET/CT is a valuable imaging tool for assessing treatment response for patients with lung cancer, though evidence for its comparative effectiveness with chest CT is still evolving. FDG PET/CT is most useful when there is clinical suspicion or other evidence for disease recurrence or metastases. The sequencing, cost analysis, and comparative effectiveness of FDG PET/CT and conventional imaging modalities in the follow-up setting need to be investigated.
Prostate-specific membrane antigen (PSMA) is a type II transmembrane glycoprotein that is highly overexpressed on prostate cancer epithelial cells and for which there is a growing body of literature ...examining the role of small-molecule and antibody radiotracers targeted against this protein for prostate cancer detection and therapy. Despite its name, PSMA is also expressed, to varying degrees, in the neovasculature of a wide variety of nonprostate cancers; indeed, the pathology literature is replete with promising immunohistochemistry findings. Several groups have begun to correlate those pathology-level results with in vivo imaging and therapy in nonprostate cancers using the same PSMA-targeted agents that have been so successful in prostate cancer. The potential to leverage radiotracers targeted to PSMA beyond prostate cancer is a promising approach for many cancers, and PSMA-targeted agents may be able to supplement or fill gaps left by other agents. However, to date, most of the reported findings with PSMA-targeted radiotracers in nonprostate malignancies have been in case reports and small case series, and the field must adopt a more thorough approach to the design and execution of larger prospective trials to realize the potential of these promising agents outside prostate cancer.
Nuclear medicine is experiencing a renaissance, with U.S. Food and Drug Administration approval recently being obtained for theranostic agents and a wide variety of such agents soon to impact patient ...care significantly in the era of precision medicine. The NETTER-1 trial demonstrated the therapeutic effect of a theranostic agent in markedly improving progression-free survival in patients with metastatic gastroenteropancreatic neuroendocrine tumors. Predominantly retrospective studies have demonstrated a significant response to
Lu-labeled agents targeting prostate-specific membrane antigen (PSMA) in patients with prostate cancer. At least 2 prospective clinical trials involving
Lu-PSMA agents are under way that will likely pave the way for Food and Drug Administration approval in the United States. A significant upside to theranostics is that patients tend to tolerate these agents better than chemotherapy. Theranostic compounds are likely to impact many cancers in the near future, not only through improvements in quality of life but also in terms of survival. This article provides an overview of already approved agents as well as those on the horizon. It is important that as these agents are clinically onboarded, nuclear medicine physicians have the expertise to deploy theranostics safely and efficiently, ensuring that these agents attain and maintain their position as leading lines of therapy in managing patients with cancer as well as becoming an important aspect of nuclear medicine practice in the future.
Purpose
This meta-analysis aims to establish the diagnostic performance of
18
F-NaF-PET/CT for the detection of bone metastases in prostate cancer patients. The performance of
18
F-NaF-PET/CT was ...compared with other imaging techniques in the same cohort of patients.
Methods
A systematic search was performed in PubMed/Medline and EMBASE (last Updated, September 28, 2018). Studies with histopathology confirmation and/or clinical/imaging follow-up as reference standard were eligible for inclusion.
Results
A total of 14 studies were included. Twelve studies including 507 patients provided per-patient basis information. The pooled sensitivity, specificity, diagnostic odds ratio (DOR) and the area under the summary receiver operating characteristics curve (AUC) of
18
F-NaF-PET/CT for the detection of bone metastases were 0.98 (95% CI 0.95–0.99), 0.90 (95% CI 0.86–0.93), 123.2 and 0.97, respectively. Seven studies provided the lesion-based accuracy information of 1812 lesions identified on
18
F-NaF-PET/CT with the pooled sensitivity, specificity, DOR and AUC of 0.97 (95% CI 0.95–0.98), 0.84 (95% CI 0.81–0.87), 206.8 and 0.97, respectively. The overall diagnostic performance of
18
F-NaF-PET/CT is superior to
99m
Tc-bone scintigraphy (AUC 0.842;
P
< 0.001; four studies) and
99m
Tc-SPECT (AUC 0.896;
P
< 0.001, four studies). Compared to
18
F NaF-PET/CT, whole-body MRI with diffusion-weighted imaging (DWI) was shown to have lower sensitivity (0.83, 95% CI 0.68–0.93), with no significant difference in the overall performance (AUC 0.947;
P
= 0.18, four studies).
Conclusion
18
F-NaF-PET/CT has excellent diagnostic performance in the detection of bone metastases in staging and restaging of high-risk prostate cancer patients. The performance of
18
F-NaF-PET/CT is superior to
99m
Tc bone scintigraphy and SPECT, and comparable to DWI–MRI.
Reliable standards and criteria for somatostatin receptor (SSTR) PET are still lacking. We herein propose a structured reporting system on a 5-point scale for SSTR PET imaging, titled SSTR-RADS ...version 1.0, which might serve as a standardized assessment for both diagnosis and treatment planning in neuroendocrine tumors. SSTR-RADS could guide the imaging specialist in interpreting SSTR PET scans, facilitate communication with the referring clinician so that appropriate workup for equivocal findings is pursued, and serve as a reliable tool for patient selection for planned peptide receptor radionuclide therapy.
The continuing adoption of prostate specific membrane antigen (PSMA)-targeted PET for prostate cancer molecular imaging requires imagers and clinicians alike to be aware of the increasing number of ...potential interpretive pitfalls that have been reported. This review summarizes and illustrates the spectrum of benign and malignant nonprostatic conditions with high PSMA-radiotracer uptake that may be mistaken for sites of prostate cancer and also discusses potential false negatives. We discuss the recent literature on the effect of androgen deprivation therapy on lesion detection. Furthermore, we briefly review the recently proposed structured reporting systems for the standardized interpretation of PSMA-targeted PET that can guide both imaging specialists and referring clinicians in the appropriate interpretation and work-up of pitfalls.
The purpose of this article is to describe the clinical utility of state-of-theart gastrointestinal transit scintigraphy, including the standardized esophageal transit, solid and liquid gastric ...emptying, small-bowel transit, colon transit, and whole-gut transit scintigraphy, with an emphasis on procedure performance.
Radionuclide gastrointestinal motility studies are noninvasive, quantitative, and physiologic diagnostic tools for evaluating patients with gastrointestinal complaints.
Castration-resistant prostate cancer (CRPC) treatment is an evolving challenge. Prostate-specific membrane antigen (PSMA)-targeted endoradiotherapy/radioligand therapy (PRLT) with small-molecule, ...urea-based agents labeled with the β-particle–emitting radionuclide lutetium-177 (177Lu) is a promising new approach.
In this systematic review and meta-analysis, we evaluated the efficacy and toxicity of PRLT.
A systematic search was performed in PubMed/Medline (last updated February 18, 2019). A total of 250 studies were reviewed, and 24 studies with 1192 patients were included in the analysis. Proportions of patients with ≥50% serum prostate-specific antigen (PSA) decrease, any PSA decrease, and any PSA increase were extracted. Proportions of patients showing any grade toxicity and those with grade 3/4 toxicities based on Common Terminology Criteria for Adverse Events (CTCAE) grading were extracted from manuscripts. Overall survival and progression-free survival were evaluated. A meta-analysis of single proportions was carried out. Furthermore, we compared the two most common PRLT agents, 177Lu-PSMA with 177Lu-PSMA-I&T, for effectiveness and toxicity.
Among the 24 included studies, 20 included data on 177Lu-PSMA-617, three included data on 177Lu-PSMA-I&T, and one study had aggregated data for 177Lu-PSMA-617 and 177Lu-PSMA-I&T. The estimated proportion of 177Lu-PSMA-617–treated patients who showed a serum PSA decrease of ≥50% with at least an 8-wk interval between therapy and PSA measurement was 0.44 (0.39; 0.50). Therapy with 177Lu-PSMA-I&T demonstrated an estimated proportion of patients with ≥50% PSA reduction to be 0.36 (0.26; 0.47). The aggregate results for men treated with more than one cycle of any kind of PRLT showed an estimated proportion of 0.46 (0.41; 0.51) for PSA response ≥50%. Regarding aggregate data from all of the PRLT agents, we found that grade 3 and 4 toxicities were uncommon, with estimated proportions from 0.01 (0.00;0.04) for nausea, fatigue, diarrhea, and elevated aspartate transaminase up to 0.08 (0.05; 0.12) for anemia. There was considerable heterogeneity among the studies in the “any-grade toxicity” groups. Meta-regression showed that more than one cycle of PRLT is associated with a greater proportion of patients with ≥50% PSA reduction. Overall survival according to pooled hazard ratios (HRs) for any PSA decline was 0.29 (0.18; 0.46), and for >50% PSA reduction was 0.67 (0.43; 1.07). Progression-free survival according to a pooled HR of >50% PSA reduction was 0.53 (0.32; 0.86).
The relatively high number of PSA responders alongside the low rate of severe toxicity reflects the potentially promising role of PRLT in treating CRPC. The ultimate utility of this treatment modality will become clearer as multiple prospective studies continue to accrue. In the interim, this systematic review and meta-analysis can serve as a compendium of effectiveness and adverse events associated with PRLT for treating clinicians.
Prostate-specific membrane antigen–targeted endoradiotherapy/radioligand therapy (PRLT) is associated with ≥50% reduction in prostate-specific antigen level in a large number of patients and a low rate of toxicity, reflecting its potential in treating castration-resistant prostate cancer. This systematic review and meta-analysis presents as a compendium of the effectiveness and adverse events related to PRLT for treating clinicians.
Prostate-specific membrane antigen–targeted endoradiotherapy/radioligand therapy appears to provide effective treatment with low toxicity rates in patients with castration-resistant prostate cancer.
Abstract
Evaluation of patients that may be infected is challenging. Imaging to identify or localize a site of infection is often limited because of the nonspecific nature of the findings on ...conventional imaging modalities. Available imaging methods lack the ability to determine if antibiotics are reaching the site of infection and are not optimized to follow response to therapy. Positron emission tomography (PET) is a method by which radiolabeled molecules can be used to detect metabolic perturbations or levels of expression of specific targets. The most common PET agent is the glucose analog 2-deoxy-2-18Ffluoro-D-glucose (18F-FDG). 18F-FDG has some applicability to localizing a site of infection, but its lack of specificity limits its usefulness. There is a need for the development of pathogen-specific PET radiotracers to address the imaging shortcomings noted above. Preclinical and clinical progress has been made, but significant challenges remain.
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