Do radioactive half-lives vary with the Earth-to-Sun distance?

Recently, Jenkins, Fischbach and collaborators have claimed evidence that radionuclide half-lives vary systematically over a ±0.1% range as a function of the oscillating distance between the Earth and the Sun, based on multi-year activity measurements. We have avoided the time-dependent instabilities to which such measurements are susceptible by directly measuring the half-life of (198)Au (t(1/2)=2.695 d) on seven occasions spread out in time to cover the complete range of Earth-Sun distances. We observe no systematic oscillations in half-life and can set an upper limit on their amplitude of ±0.02%.     

Are all urgent nephrostomies that urgent?

Purpose

To investigate if the presence of systemic inflammatory response syndrome (SIRS) in patients with urinary tract obstruction at time of presentation to the emergency department correlates with a subsequent positive urine culture and to determine if it could be used as a tool to predict the urgency of a percutaneous nephrostomy (PCN). The secondary aim of the study was to assess the incidence of in-hour and after-hour emergent PCNs performed in a tertiary center which has both interventional radiological and urological expertise.

Methods and materials

Emergent adult PCN cases referred from the emergency department between 2011 and 2016 were identified retrospectively. Urine culture results, clinical features of SIRS, timing of procedure, and radiological findings were analyzed.

Results

A total of 110 patients met the inclusion criteria. There were a total of 60 male and 50 female patients with a mean age of 62 (age range 18–99 years). Ninety-two (83%) PCN patients were referred and performed on after-hours with the remaining 18 patients performed in-hours. There were 53 (48%) patients that met the criteria for obstruction with SIRS and 57 (52%) patients with obstruction without SIRS. The number of after-hours PCN performed in both groups was equal at 46 patients each. The most common cause of obstruction in the SIRS group was stone related in 31 (58%) patients. Whereas, the most common cause of obstruction in the non-SIRS group was due to malignancy in 26 (45%) cases. An elevated temperature and heart rate were the most common features of SIRS at 96 and 83% respectively in the SIRS group. An organism was isolated in 35 (67%) out of the 52 urine culture results obtained for the SIRS group. No organism was isolated in 42 (95%) out of the 44 urine culture results obtained in the non-SIRS group. Statistical analysis using Fisher’s test revealed that the association between obstruction without SIRS and a negative urine culture result was statistically significant (p <?0.0001).

Conclusion

A large percentage (50%) of PCN cases performed after-hours could have been performed during daytime hours instead due to the absence of infection. This would be in line with the practices of some centers that consider an infected obstructed kidney as the only absolute indication for emergent decompression overnight. The study also demonstrates that the absence of a SIRS in a patient with urinary tract obstruction correlates well with a negative urine culture result from the nephrostomy specimen which has a high negative predictive value for excluding pyonephrosis.

     

Nanoradiopharmaceuticals: is that the future for nuclear medicine?

New advances in nanotechnology has been responsible for the development of a new science called nanomedicine. In the recent years many discoveries as nanotubes and nanoparticles, especially for pharmaceuticals use, has increasing the application of nanotechnology for medical purposes. In this direction the development of nanoradiopharmaceuticals are also promising as novel radiopharmaceuticals. In this study we made an extensive overview of the most recent advantages in this field of nanotechnology and a fully application to radiopharmaceuticals. Despite, we gaive some nanoradiopharmaceuticals already developed and under investigation for clinical use. The results described that is possible to make nanoradiopharmaceuticals of two ways. The first one directly: nanoencapsulating an already radioactive radiopharmaceuticals. And the second way is nanoencapsulating a non-radioactive ligand for posterior labeling with a radioisotope alikes 99mTc. In both cases the nanoradiopharmaceuticals are acquired. We ended that nanoradiopharmaceuticals are feasible and may represent the future of the nuclear medicine.     

Why is Marine combat mortality less than that of the Army?

Data from recent wars indicate that a wounded Marine had a 20% lower risk of dying than an Army soldier. Possible reasons for this difference are (1) Navy care is superior, (2) soldiers sustained more severe wounds, and (3) the services count casualties differently. Injury severity was measured in random samples of Marines and soldiers that were selected from the Wound Data and Munitions Effectiveness Team database. There was no difference in the lethality of injury and the prevalence of lifesaving first aid. Wounded Marines were more likely to wear protective vests, and this decreased Marine mortality in Vietnam. Hospitalized Marines had lower Injury Severity Scores and were less likely to be returned to duty without first being admitted to a medical treatment facility. Lower Marine combat mortality is primarily the result of the fact that a Marine with a minor soft tissue wound was more likely to be hospitalized than was a soldier with a similar injury.     

Should we obtain informed consent for examinations that expose patients to radiation?

OBJECTIVE: Concern about the radiation-related risks associated with medical imaging is currently a hot topic in both the scientific and lay press as well as gaining a growing awareness from regulatory and legislative organizations. As a result, there is a growing debate about whether or not we should obtain informed consent from patients-in particular, children and their parents-for examinations that expose patients to radiation. In this article, we will discuss the difficulties and challenges of informed decision making and obtaining consent for radiologic examinations. CONCLUSION: We provide our perspectives about the issue of whether informed consent should be required for diagnostic imaging procedures in children, although many of the points also apply to the adult population, and we discuss the dilemmas related to the process of designing and obtaining informed consent for radiologic procedures.     

Are fibroids that become endocavitary after uterine artery embolization necessarily a complication?

OBJECTIVE: This commentary deals with the study by Verma et al. discussing submucosal and endocavitary fibroids after uterine artery embolization (UAE). CONCLUSION: UAE can infarct fibroids. Fibroids spontaneously infarct after childbirth. Because the postpartum cervix is patulous, infarcted fibroids that fall into the uterine cavity easily exit the uterus. Each patient contemplating UAE should anticipate that infarcted fibroids bordering on or inside the uterine cavity may require cervical dilatation or hysteroscopic resection for removal. The addition of either of these two gynecology procedures should not necessarily be regarded as a UAE complication or treatment failure.     

Cirrhotic liver: What's that nodule? The LI‐RADS approach

The Liver Imaging Reporting and Data System (LI‐RADS) is an American College of Radiology (ACR)‐endorsed diagnostic system of standardized terminology, interpretation, and reporting for imaging examinations of the liver in patients at high risk for hepatocellular carcinoma (HCC). LI‐RADS assigns a category to observations in the liver indicating the likelihood of benignity or HCC. LI‐RADS categories include LR‐1: Definitely Benign, LR‐2: Probably Benign, LR‐3: Intermediate Probability for HCC, LR‐4: Probably HCC, LR‐5: Definite HCC, LR‐5V: Definite HCC with Tumor in Vein, LR‐Treated: Treated HCC, LR‐M Probable Malignancy, not specific for HCC. This article reviews the types of nodules seen in the cirrhotic liver, examines core LI‐RADS concepts and definitions, and utilizes the LI‐RADS v2014 algorithm to categorize representative observations depicted at magnetic resonance imaging in a case‐based approach. J. Magn. Reson. Imaging 2016;43:281–294.     

Dentate nucleus T1 hyperintensity: is it always gadolinium all that glitters?

In the last few years, several scientific papers and reports have demonstrated magnetic resonance (MR) signal intensity (SI) changes on pre-contrast T1-weighted images following multiple gadolinium-based contrast agents (GBCA) administrations, particularly following the exposure to linear GBCAs. Pathological animal and human post-mortem studies have confirmed the relationship between this radiological finding and the presence of gadolinium accumulation in vulnerable brain regions in patients with normal renal function. In this short communication, we report the case of a 15-year-old patient affected by b-cell acute lymphoblastic leukemia (bALL) who developed a hyperintense signal in the dentate nuclei following multiple administrations of a macrocyclic GBCA. The purpose of this report is to discuss possible differential diagnoses of this radiological finding with special focus on the differentiation between iron or manganese accumulation, post-irradiation changes and GBCA-related Gd deposition, highlighting the importance of the acquisition of accurate clinical data to improve our scientific knowledge.     

Radiation hormesis,or, could all that radiation be good for us?

OBJECTIVE: Nuclear medicine technologists work under significant radiation protection constraints. These constraints are based on the linear no-threshold (LNT) radiation paradigm, which was developed in the 1960s and was based largely on the deleterious effects of radiation as they were understood at the time. More recently, the theory of radiation hormesis, or a beneficial effect of low-level exposure to radiation, has gained recognition. This article reviews the history of attitudes toward radiation, describes the radiation hormesis hypothesis, examines some of the evidence that supports it, and suggests ways that radiation protection regulations might change if the hypothesis were to become accepted.     

Precision of bone densitometry measurements: when is change true change and does it vary across bone density values?

The precision error of the bone densitometer is used to interpret significant change in bone mineral density (BMD) in serial studies. The precision error can be expressed as standard deviation (SD) or coefficient of variation (CV). The aims of this study are to determine the precision error over a range of BMD values and to demonstrate the application of the precision error in clinical practice. A bone phantom was used consisting of a perspex block with eight compartments containing varying amounts of hydroxyapatite powder to simulate a range of bone densities. The block was scanned 21 times and manual regions placed over each compartment to measure the BMD in each compartment. There were no significant differences in the variances or SD for all eight compartments, that is, over the range of BMD normally encountered in clinical practice. However, the calculated CV show a progressive fall in values as the BMD rises. Therefore, the SD should be used to calculate significant BMD change. In a practise with quality control procedures in place to detect calibration drift and with appropriately trained personnel, a change of approximately 0.05 g/cm2 is generally regarded as being a significant change at a 95% confidence level.