Gastroparesis is a disorder characterized by a delay in gastric emptying in the absence of mechanical obstruction. There are previous reported cases of gastroparesis induced by vaccinations, ...including smallpox, tetanus, anthrax, and hepatitis B immunizations (2). A nuclear medicine gastric emptying study showed 15% of gastric contents remaining at 4 hours, consistent with delayed gastric emptying (Figure 1).
A new era of precision diagnostics and therapy for patients with neuroendocrine neoplasms began with the approval of somatostatin receptor (SSTR) radiopharmaceuticals for PET imaging followed by ...peptide receptor radionuclide therapy (PRRT). With the transition from SSTR-based γ-scintigraphy to PET, the higher sensitivity of the latter raised questions regarding the direct application of the planar scintigraphy-based Krenning score for PRRT eligibility. Also, to date, the role of SSTR PET in response assessment and predicting outcome remains under evaluation. In this comprehensive review article, we discuss the current role of SSTR PET in all aspects of neuroendocrine neoplasms, including its relation to conventional imaging, selection of patients for PRRT, and the current understanding of SSTR PET-based response assessment. We also provide a standardized reporting template for SSTR PET with a brief discussion.
Radioligand therapy (RLT) with 177LuLu-DOTA-TATE is a standard of care for adult patients with somatostatin-receptor (SSTR)-positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Taking ...advantage of this precision nuclear medicine approach requires diligent monitoring and surveillance, from the use of diagnostic SSTR-targeted radioligand imaging for the selection of patients through treatment and assessments of response. Published evidence-based guidelines assist the multidisciplinary healthcare team by providing acceptable approaches to care; however, the sheer heterogeneity of GEP-NETs can make these frameworks difficult to apply in individual clinical circumstances. There are also contradictions in the literature regarding the utility of novel approaches in monitoring and surveilling patients with GEP-NETs receiving RLT. This article discusses the emerging evidence on imaging, clinical biochemistry, and tumor assessment criteria in the management of patients receiving RLT for GEP-NETs; additionally, it documents our own best practices. This allows us to offer practical guidance on how to effectively implement monitoring and surveillance measures to aid patient-tailored clinical decision-making.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
PSMA-targeted radiopharmaceutical therapy is an established treatment option for metastatic castration-resistant prostate cancer (mCRPC). However, response rates and duration using
177
Lu-PSMA-617 ...vary considerably between patients. Quantitative
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Lu SPECT imaging is one approach that may be leveraged to more closely monitor inter-cycle response, as well as patient-specific absorbed doses. In this work, we describe our experience implementing quantitative imaging throughout the course of
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Lu-PSMA treatment, including serial SPECT imaging to monitor response and for individualized dosimetry. We also describe our imaging protocols and dose calculation workflows for 3D voxelized patient-specific organ and tumor dosimetry, including a review of the current landscape and efforts towards harmonized dosimetry.
Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogenous group of malignancies originating from neuroendocrine cells of the gastrointestinal tract, the incidence of which has been ...increasing for several decades. While there has been significant progress in the development of therapeutic options for patients with advanced or metastatic disease, these remain limited both in quantity and durability of benefit. This review examines the latest research elucidating the mechanisms of both up-front resistance and the eventual development of resistance to the primary systemic therapeutic options including somatostatin analogues, peptide receptor radionuclide therapy with lutetium Lu 177 dotatate, everolimus, sunitinib, and temozolomide-based chemotherapy. Further, potential strategies for overcoming these mechanisms of resistance are reviewed in addition to a comprehensive review of ongoing and planned clinical trials addressing this important challenge.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract Prostate cancer (PCa) seldom metastasizes to the thyroid gland, and only a limited number of cases are documented in the literature. The application of a relatively recent and highly ...sensitive imaging technique, prostate-specific membrane antigen (PSMA) positron emission tomography—computed tomography (PET/CT), has enhanced the identification of metastatic disease. Nevertheless, as PSMA is expressed in various tissue types, the clinical importance of a PSMA-avid thyroid lesion remains largely uncertain. A minor, yet noteworthy, percentage of these lesions are ultimately determined to be malignant. Here we describe the case of a 70-year-old man with a past medical history of Lynch syndrome who presented to an outpatient oncologic clinic for management of very high risk localized PCa. He developed metastatic recurrence and his disease progressed through several lines of therapy, including immunotherapy and targeted treatments. He was found to have a new, intense PSMA uptake in an existing, previously benign thyroid nodule. Sonographic evaluation revealed changing morphology despite grossly stable size. Repeat biopsy confirmed the unusual finding of PCa metastasis to a known thyroid nodule. The shift in PSMA avidity played a pivotal role in discerning this metastatic deposit. There is a potential risk that such lesions may be inadequately acknowledged. The impact of the patient’s Lynch syndrome on this presentation remains uncertain.
PET/MR Imaging of the Pancreas Mallak, Nadine; Hope, Thomas A; Guimaraes, Alexander R
Magnetic resonance imaging clinics of North America,
08/2018, Volume:
26, Issue:
3
Journal Article
Peer reviewed
PET/MR imaging has the potential to markedly alter pancreatic care in both the malignant, and premalignant states with the ability to perform robust, high-resolution, quantitative molecular imaging. ...The ability of PET/MR imaging to monitor disease processes, potentially correct for motion in the upper abdomen, and provide novel biomarkers that may be a combination of MR imaging and PET biomarkers, offers a unique, precise interrogation of the pancreatic milieu going forward.
Objectives: CZT cameras provide high quality myocardial perfusion scans (MPS), however, the image quality and accuracy of CZT MPS using a stress-first protocol is less well validated in obese patient ...population. The purpose of our study is to evaluate the image quality and accuracy of CZT MPS in patients with BMI above 35. Methods: A retrospective analysis of all patients with BMI above 35 who underwent stress-first (rest images obtained only if stress is abnormal) CZT MPS between January 1st 2015 and October 30 2015. All stress myocardial perfusion scans including supine and prone images were interpreted independently by two reviewers blinded to history and prior imaging with a final consensus reading. The quality of the MPS was graded on a scale from 1 to 4 (1: Poor/Non-diagnostic; 2: Borderline; 3: Good; 4: Excellent). The interpretation of MPS followed a 5-point scale (1: Abnormal, 2: Probably Abnormal, 3: Equivocal, 4: Probably Normal and 5: Normal). Patient follow-up data was obtained from electronic charts. Coronary events were defined as cardiac death, nonfatal myocardial infarction and revascularization. Results: 105 patients, 65 males and 40 females, age range 37-87, were evaluated. The BMI of the patients ranged from 35.1 to 42.7 (median = 36.9). The image quality score was assessed as 3 or 4 in 83 patients (79.1 %), 2 in 18 patients (17.1%) and 1 in 4 patients (3.8%). 70 patients (66.7%) had normal or probably normal scans, 17 (16.2%) patients had abnormal or probably abnormal stress scans and 18 (17.1 %) patients had equivocal stress scans. 8 patients had no follow-up visit; in the remaining 97 patients, the median follow-up was 16.1 months (range: 0.7 to 23.1 months). There were a total of 6 cardiac events in the entire patient population. In 70 patients with normal/probably normal scans, there was 1 coronary event (1.4%) over a follow-up period of a median of 16.3 months (range: 3.1 to 23.1 months; at least 12 months in 51 patients). In 18 patients with equivocal scans there was 1 coronary event (5.55%) over a follow-up period of a median of 15.1 months (range: 0.7 to 20.6 months). There were 4 cardiac events In 17 patients with abnormal scans (23.5%, P<0.01 compared to normal group). Conclusion: CZT MPS stress-first myocardial perfusion imaging provides high-quality images in the vast majority of obese patients and identifies patients at high-risk for coronary events.
e18077 Background: To investigate the incidence, features, and clinical characteristics of unexpected prostate-specific membrane antigen (PSMA) uptake within the thyroid gland of patients with ...prostate cancer (PCa) who underwent F-18 DCFPyL PSMA PET/CT. Methods: We retrospectively reviewed a cohort of 1148 PCa patients who underwent PSMA PET/CT at our institution between 11/2021 - 09/2023. Scans with abnormal thyroid uptake were identified. Clinical data included patient demographics, PCa history, Gleason score, prostate specific antigen (PSA), ultrasonography (US), fine needle aspirate (FNA) / thyroidectomy, histopathology, and history of neck radiation or prior malignancy. Each scan was further analyzed with lesion-specific iso-contour method (42% cutoff) to obtain PET parameters (most prominent nodule SUVmax, SUVmean, PSMA volume, tumor lesion PSMA, contralateral gland SUVmax, SUVmax-nodule / SUVmax-contralateral gland ratio, most prominent PCa lesion SUVmax), PCa tumor distribution, and tumor volume. CT-related variables (nodule number, dominant nodule size, short/long axis ratio, CT-HU, integral total value) were also collected. Pearson's chi-square testing and Kruskal-Wallis testing was performed for categorical and nonparametric data respectively. Receiver operating characteristic (ROC) curves with area under curve (AUC) value were determined using IBM SPSS (version 29.0). Results: Of the 1148 PSMA PET/CTs, 60 (5.2%) had abnormal thyroid uptake (nodular: 58, diffuse: 2). Diffuse uptake was found to represent thyroiditis in both patients. 43 (56.7%) had an US, 20 (33%) were biopsied (11 benign, 5 indeterminate, 4 malignant), and 5 (8.3%) pursued thyroidectomy (3 malignant, 2 benign). 22 patients (36.7%) had histopathology data and 5 malignancies (2 PCa, 1 CLL, 2 primary thyroid) were identified. Nodule size was larger in those who had an US relative to those who did not. Among those with US data, no significant differences in clinical or histopathological parameters were seen. SUVmax (p: 0.01; AUC: 0.876, 95%CI: 0.731-1.0) and SUVmean (p:0.01; AUC: 0.871, 95%CI: 0.722-1.0) were higher in the malignant group. Nodule SUVmax/contralateral gland SUVmax ratio showed borderline significance (p = 0.05). Conclusions: Incidental PSMA PET uptake in the thyroid gland is seen in approximately 5% of patients. Focal uptake should prompt consideration of US and FNA due to the possibility of prostate cancer metastasis and thyroid cancer. SUVmax/mean is higher in malignant lesions.
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