Impact of cell geometry, cellular uptake region, and tumour morphology on Ac and Lu dose distributions in prostate cancer.

Background: Radiopharmaceutical therapy with Ac- and Lu-PSMA has shown promising results for the treatment of prostate cancer. However, the distinct physical properties of alpha and beta radiation elicit varying cellular responses, which could be influenced by factors such as tumour morphology. In this study, we use simulations to examine how cell geometry, region of pharmaceutical uptake within the cell to model different internalization fractions, and the presence of tumour hypoxia and necrosis impact nucleus absorbed doses and dose heterogeneity with Ac and Lu.

The Elusive Neuroendocrine Tumor: Finding the Ectopic ACTH Source 16 Years After the Diagnosis of Cushing Syndrome.

Ectopic adrenocorticotropin hormone (ACTH) syndrome (EAS) accounts for the minority of cases of Cushing syndrome. Up to 20% of these cases remain occult, despite multiple imaging attempts to localize the ACTH-producing tumor. Here we describe long-term follow-up of a 41-year-old woman, with ectopic Cushing syndrome initially classified as occult due to negative localization studies, who had bilateral adrenalectomy to manage hypercortisolism.

PSMA-Hornet: Fully-automated, multi-target segmentation of healthy organs in PSMA PET/CT images.

Background: Prostate-specific membrane antigen (PSMA) PET imaging represents a valuable source of information reflecting disease stage, response rate, and treatment optimization options, particularly with PSMA radioligand therapy. Quantification of radiopharmaceutical uptake in healthy organs from PSMA images has the potential to minimize toxicity by extrapolation of the radiation dose delivery towards personalization of therapy. However, segmentation and quantification of uptake in organs requires labor-intensive organ delineations that are often not feasible in the clinic nor scalable for large clinical trials.

Comparing digital to analog prostate-specific membrane antigen-targeted piflufolastat 18 F PET/CT in prostate cancer patients in early biochemical failure.

Purpose: Prostate-specific membrane antigen (PSMA) positron emission tomography/computer tomography (PET/CT) in prostate cancer patients with biochemical failure(BCF) showslimited sensitivity when the prostate-specific antigen(PSA) <0.5 ng/mL. The development of digital PET/CT has greatly improved smaller lesion detection.

Blinded Clinical Evaluation for Dementia of Alzheimer's Type Classification Using FDG-PET: A Comparison Between Feature-Engineered and Non-Feature-Engineered Machine Learning Methods.

Background: Advanced machine learning methods can aid in the identification of dementia risk using neuroimaging-derived features including FDG-PET. However, to enable the translation of these methods and test their usefulness in clinical practice, it is crucial to conduct independent validation on real clinical samples, which has yet to be properly delineated in the current literature.

Objective: In this paper, we present our efforts to enable such clinical translational through the evaluation and comparison of two machine-learning methods for discrimination between dementia of Alzheimer's type (DAT) and Non-DAT controls.

Diagnostic performance of F-DCFPyL positron emission tomography/computed tomography for biochemically recurrent prostate cancer and change-of-management analysis.

Introduction: Conventional imaging (CI) performs poorly to identify sites of disease in biochemically recurrent prostate cancer. Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) is most studied but has a very short half-life. This study reports the diagnostic performance of the novel prostate-specific membrane antigen (PSMA) radiotracer F-DCFPyL using real-life data and tumor board simulation to estimate the impact of F-DCFPyL PET on patient management.

Ureteral Metastasis From Prostate Cancer: A PSMA PET Pitfall.

A 72-year-old man with a history of prostate adenocarcinoma initially managed by radical prostatectomy and salvage radiation therapy underwent resection of a left vas deferens recurrence identified on PSMA PET. Despite an initial response, PSA failed to fall below 3.5 ng/L, prompting re-evaluation with PSMA PET/CT: a left distal hydroureter with presumed physiologic urine activity remains despite diuretic administration.

Incidental Hydroxyapatite Ocular Implant Uptake on Bone Scan Done for Prostate Cancer Staging: Case Report and Brief Review.

A 74-year-old man recently diagnosed with high-risk prostate cancer with high serum prostate specific antigen was referred to nuclear medicine for a technetium-99m-methylene diphosphonate (Tc-99m MDP) bone scan. On delayed three-hour anterior planar image, an unexpected round focus of intense uptake was found overlying the right orbit. Single-photon emission computed tomography/computed tomography localized the uptake to an ocular prosthesis.

F-fluorodeoxyglucose positron emission tomography/computed tomography in extensive bland portal vein thrombosis from retroperitoneal adenocarcinoma.

A 73-year-old woman undergoing hormone therapy for previously treated localized breast cancer presented at oncology follow-up 4 years after mastectomy/radiation therapy with weight loss, night sweats, and abdominal pain. Contrast computed tomography (CT) abdomen revealed a soft-tissue mass posterior to the pancreas, several enlarged retroperitoneal lymph nodes, and a dilated portal vein. On 18F-fluorodeoxyglucose positron emission tomography/CT, metabolic activity extended along the portal vein, outlining most of the liver venous system.

F-fluorocholine positron emission tomography-computed tomography (F-FCH PET/CT) for staging of high-risk prostate cancer patients.

Introduction: We sought to evaluate the diagnostic performance of F-fluorocholine positron emission tomography-computed tomography (F-FCH PET/CT) for initial staging of patients with high-risk prostate cancer. Secondary objectives were to compare the value of F-FCH PET/CT to conventional imaging modalities and to evaluate its clinical impact.

Methods: We conducted a retrospective study of 76 patients who underwent F-FCH PET/CT for initial staging of high-risk prostate cancer.

I-131 Radiation-Induced Myelosuppression in Differentiated Thyroid Cancer Therapy.

Radioactive iodine (RAI) treatment of differentiated thyroid cancer has been used in clinical practice for almost 60 years and is generally accepted to be a safe and efficacious treatment. Severe toxicity in the form of radiation pneumonitis, sometimes progressing to fibrosis, and bone marrow suppression are reported but remain rare. We present a case of severe myelosuppression requiring hospitalization and transfusion support in an otherwise well, young female patient who had received 175 mCi I-131 for low-volume micronodular lung disease one month prior, with a cumulative lifetime administered activity of 575 mCi.

Asthmatic Exacerbation as a Cause of False-Positive Whole-Body Iodine Scan in a Patient With Treated Papillary Thyroid Carcinoma.

A 44-year-old woman was found to have new diffuse lung uptake on a follow-up whole-body I scan 1 year after being treated with surgery and radioactive iodine for papillary thyroid cancer. However, subsequent CT thorax and thyroglobulin levels were both unremarkable. Shortly after, she presented with respiratory symptoms, exhibiting end-expiratory wheezing on auscultation.

Small Lymph Node Metastasis Detected by 68Ga-Prostate-Specific Membrane Antigen But Not 18F-Fluciclovine PET/CT in Low-Prostate-Specific Antigen Biochemical Recurrence of Prostate Cancer.

A 58-year-old man with Gleason 4+3 prostate cancer was initially treated by radical prostatectomy followed by salvage radiotherapy to the prostate bed for postoperative biochemical failure. One year later, F-fluorocholine PET/CT detected a pelvic lymph node recurrence, which was treated with radiation therapy and 6 months of androgen deprivation. PSA started to rise again 18 months later, but F-fluciclovine PET/CT failed to demonstrate the site of recurrence at a PSA of 0.

Erdheim-Chester Disease: The Importance of Information Integration.

Background: Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis disorder that utilizes the RAS-RAF-MEK-ERK pathway. It has a highly variable clinical presentation, where virtually any organ can be involved, thus having the potential of posing a great diagnostic challenge. Over half of the reported cases have the BRAF V600E mutation and have shown a remarkable response to vemurafenib.

Biopsy-Proven Diffuse Mediastinal Prostate Cancer Metastases Negative on 18F-Fluorocholine, Diagnosed on 68Ga-PSMA and 18F-PSMA PET/CT.

A 72-year-old man with prostate cancer (stage T3b, Gleason score 7) treated by radical prostatectomy was found to have biochemical failure (prostate-specific antigen 8.5 ng/mL) and a suspicious growing nodularity at the left prostate bed on MRI. F-fluorocholine PET/CT failed to demonstrate any site of uptake suggestive of malignancy.

Temperament and character personality dimensions in nitrate-tilt-induced vasovagal syncope patients.

Objective: Vasovagal syncope (VVS) is a clinical syndrome that is characterized by a transient loss of consciousness and postural tone that are due to a temporary, spontaneously self-terminating global cerebral hypoperfusion. It is known that personality modulates the individual's sensitivity to stressors and that emotional arousal and psychologic uncertainty are conditions that contribute to vasodepressor syncope. Therefore, it is postulated that the personality characteristics of VVS patients could play a role in the pathophysiology of VVS.