An analytic model to calculate Voxel S-Values for 177^{177}Lu

Objective: $^{177}$Lu is one of the most employed isotopes in targeted radionuclide therapies and theranostics, and 3D internal dosimetry for such procedures has great importance. Voxel S-Values (VSVs) approach is widely used for this purpose, but VSVs are available for a limited number of voxel dimensions. The aim of this work is to develop an analytic model for the calculation of $^{177}$Lu-VSVs in any cubic voxelized geometry of practical interest. Approach: Monte Carlo (MC) simulations were implemented with the toolkit GAMOS to evaluate VSVs in voxelized geometries of soft tissue from a source of $^{177}$Lu homogeneously distributed in the central voxel. Nine geometric setups, containing 15x15x15 cubic voxels of sides l ranging from 2 mm to 6 mm, in steps of 0.5 mm, were considered. For each l, the VSVs computed as a function of the "normalized radius", Rn = R/l (with R = distance from the center of the source voxel), were fitted with a parametric function. The dependencies of the parameters as a function of l were then fitted with appropriate functions, in order to implement the model for deducing $^{177}$Lu-VSVs for any l within the aforementioned range. Main results: The MC-derived VSVs were satisfactorily compared with literature data for validation, and the VSVs computed with the analytic model agree with the MC ones within 2\% for Rn $\leq$ 2 and within 6\% for Rn > 2. Significance: The proposed model enables the easy and fast calculation, with a simple spreadsheet, of $^{177}$Lu-VSVs in any cubic voxelized geometry of practical interest, avoiding the necessity of implementing ad-hoc MC simulations to estimate VSVs for specific voxel dimensions not available in literature data.Comment: 16 pages, 7 figures, first round review in "Biomedical Physics & Engineering Express

What is New on Thyroid Cancer Biomarkers

Thyroid cancer harbours in about 5% of thyroid nodules. The majority of them are well-differentiated cancers originating from the follicular epithelium, and are subdivided into papillary and follicular carcinomas. Undifferentiated carcinomas and medullary thyroid carcinomas arising from C cells are less common

PET-based artificial intelligence applications in cardiac nuclear medicine.

In the recent years, artificial intelligence (AI) applications have gained interest in the field of cardiovascular medical imaging, including positron emission tomography (PET). The use of AI in cardiac PET imaging is to date limited, although first, important results have been shown, overcoming technical issues, improving diagnostic accuracy and providing prognostic information. In this review we aimed to summarize the state-of-the-art regarding AI applications in cardiovascular PET

Gliomas with intratumoral abscess formation: Description of new cases, review of the literature, and the role of 99mTC-Leukoscan

Abstract Abscess formation within a brain tumor is uncommon. Intrasellar or parasellar tumors are the most common neoplasms that develop such complications. Cerebral gliomas with abscesses are extremely rare. In this paper three rare cases of glioma associated with abscess formation are described. The diagnosis of brain tumor associated with abscess is particularly difficult by conventional neuroradiological studies. 99m Tc-labeled sulesomab can be useful in the diagnosis of brain tumors with intratumoral abscesses. There are no precise guidelines for the diagnosis and treatment of cerebral gliomas associated with abscesses formation for the low number of cases reported to date. Appropriate treatment, aimed at radical surgery, and a suitable antibiotic-protocol, deferring adjuvant postoperative therapy, is associated with a more favorable outcome. A review of the pertinent literature is also performed

An uncommon case of Marine-Lenhart syndrome

The term Marine-Lenhart syndrome describes the association between Graves' disease and autonomously functioning thyroid nodules (AFTN), such as toxic adenoma or toxic multinodular goiter. The two diseases may coexist or may be present at different moments in the same patient. In the literature, there are many reports on the development of Graves' disease after radioiodine treatment for AFTN, but very little information may be found on the occurrence of AFTN after radioiodine therapy for Graves' disease. We describe here the case of a female patient with Graves' disease who was successfully treated with radioiodine for Graves' disease, returning to normal thyroid function. Three years later, biochemical analysis and ultrasound examination identified a thyroid nodule that progressively increased in size. The 99mTc-pertechnetate scintigraphy showed avid uptake in the right lobule, which corresponded to a nodular lesion consistent with AFTN

Cross-Sectional Evaluation of Kidney Function in Hospitalized Patients: Estimated GFR Versus Renal Scintigraphy

Background/Aims: Accurate staging of chronic kidney disease (CKD) is very important. We tried to identify difference in GFR evaluation between CKD-EPI and Gates method with renal scintigraphy and which variables are associated with these differences. Methods: We retrospectively reviewed the records of 341 patients who underwent dynamic renal scintigraphy in the last 5 years. Patients were categorized according to KDIGO staging I to V, using the eGFR calculated with the CKD-EPI equation. Secondarily, we stratified patients according to treatment with renin-angiotensin system (RAS) inhibitors. Results: Gates method tends to underestimate GFR especially in CKD stage I (mean -22.2 ml/min) and II (mean -12.5 ml/min). The division in quartiles of ages showed an underestimation of GFR only in the first quartile of age (< 50 years old). Gates method underestimation of GFR was more pronounced in stage I patients treated with RAS inhibitors (mean -34.6 ml/min). The same occurs in stage II, even though to a lesser extent. Conclusion: The assessment of GFR by the Gates method must be carefully considered in the early stages of CKD, especially in younger patients. Moreover, the difference is more pronounced in patients treated with RAS inhibitors. Longitudinal studies will prove which method better predicts cardiovascular or renal events

Clinical-Forensic Autopsy Findings to Defeat COVID-19 Disease: A Literature Review

The severe acute respiratory syndrome (SARS)-CoV-2 was identified for the first time in China, in December 2019. Confirmed cases of COVID-19 have been reported around the world; indeed, this infection has been declared a pandemic. Consequently, the scientific community is working hard to gain useful information about the history of this virus, its transmission, diagnosis, clinical features, radiological findings, research and development of candidate therapeutics as well as vaccines. This review aims to analyze the diagnostic techniques used to ascertain the COVID-19 infection, critically reviewing positive points and criticism for forensic implications, obviously including autopsy. Finally, this review proposes a practical workflow to be applied in the management of corpses during this outbreak of the COVID-19 infection, which could be useful in cases of future infectious disease emergencies. Analyzing the diagnostic methods, to date, virus nucleic acid RT-PCR represents the standard method used to ascertain the COVID-19 infection in living subjects and corpses, even if this technique has several criticisms: mainly, the staff should be highly specialized, working in high-throughput settings, able to handle high workloads and aware of health risks and the importance of the results. Thus, IgG/IgM serological tests have been developed, overcoming RT-qPCR duration, costs, and management, not requiring highly trained personnel. Nevertheless, serological tests present problems; the WHO recommends the use of these new point-of-care immunodiagnostic tests only in research settings. Furthermore, nothing has yet been published regarding the possibility of applying these methods during post-mortem investigations. In light of this scenario, in this review, we suggest a flow chart for the pathologist called on to ascertain the cause of death of a subject with historical and clinical findings of COVID-19 status or without any anamnestic, diagnostic, or exposure information. Indeed, the literature data confirmed the analytical vulnerabilities of the kits used for laboratory diagnosis of COVID-19, particularly during postmortem examinations. For these reasons, autopsy remains the gold standard method to ascertain the exact cause of death (from or with COVID-19 infection, or other causes), to consequently provide real data for statistical evaluations and to take necessary measures to contain the risks of the infection. Moreover, performing autopsies could provide information on the pathogenesis of the COVID-19 infection with obvious therapeutic implications

Quantitative comparison between amyloid deposition detected by (99m)Tc-Diphosphonate imaging and myocardial deformation evaluated by strain echocardiography in transthyretin-related cardiac amyloidosis.

Methods and results 28 patients with transthyretin mutation and a group of 14 controls underwent echocardiography to quantify left ventricular (LV) dimensions and function, and global (G) longitudinal (L), radial (R) and circumferential (C) strain (S). 99mTc-3, 3-diphosphono-1, 2-propanodicarboxylic-acid-scintigraphy (99mTc-DPD) was used to quantify cardiac amyloidosis (CA). 99mTc-DPD revealed accumulation in 14 of 28 patients (CA-group) and no accumulation (no CA-group) in 14 patients. Cardiac accumulation was mild-moderate in 5 (Mild-Moderate CA-group) and severe in 9 patients (Severe CA-group). Severe CA-group showed higher values of LV septal thickness (LVST), posterior wall thickness and E/E' ratio than the no CA-group and the control group (adj. p<0.05). Ejection fraction was similar among groups (p=0.65). GLS was lower (p=<0.001) in severe CA-group (-12.2 ± 4.5) respect to no CA-group (-19.3 ± 3.0) and to the control group (-20.9 ± 2.5). On the contrary, GCS and GRS were lower (p=<0.05) in mild-moderate CA-group (-10.8 ± 4.1 and 9.5 ± 5.7, respectively) respect to the severe CA-group (-18.9 ± 5.1 and 23.9 ± 6.3 respectively), no CA-group (-19.2 ± 4.1 and 28.4 ± 10.2 respectively) and the control group (-23.9 ± 4.4 and 29.9 ± 8.7 respectively). A correlation was found between the scintigraphic heart retention (HR) index and LVST (r=0.72; p<0.001) and E/E' (r=0.46; p=0.03). An inverse tendency was observed between HR and GLS (r=−0.40; p=0.06)

Gastroparesis in Adolescent Patient with Type 1 Diabetes: Severe Presentation of a Rare Pediatric Complication

Gastroparesis is a long-term complication of diabetes related to autonomic neuropathy. It is characterized clinically by delayed gastric emptying and upper gastrointestinal symptoms, including early satiety, postprandial fullness, nausea, vomiting, and abdominal pain. Gastric emptying scintigraphy is the gold standard for diagnosis as it reveals delayed gastric emptying. Therapeutic strategies include dietary modifications, improvement of glycemic control, and prokinetic drugs. Case descriptions of diabetic gastroparesis in pediatric ages are very scarce. We report the case of a 16-year-old adolescent with severe presentation of diabetic gastroparesis. She presented with recurrent episodes of nausea, vomiting and abdominal pain which led progressively to reduced oral intake and weight loss. Her past glycemic control had been quite brittle, as demonstrated by several hospitalizations due to diabetic ketoacidosis and recurrent episodes of severe hypoglycemia. After the exclusion of infectious, mechanical, metabolic, and neurological causes of vomiting, a gastric emptying scintigraphy was performed, leading to the diagnosis of gastroparesis. Treatment with metoclopramide was started with progressive relief of symptoms. To improve glycemic control, insulin therapy with an advanced hybrid, closed loop system was successfully started. Pediatricians should consider diabetic gastroparesis in children and adolescents with long-standing, poorly controlled diabetes and appropriate symptomology