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Quantification in Emission Tomography
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Brian F. Hutton, Kjell Erlandsson, Kris Thielemans
Sometimes lean body weight is used instead of body weight to account for the fact that there is not normally significant tracer uptake in fatty tissue. The result is a unit-less quantity. The activity Ainj is measured in a dose-calibrator, typically an ionization chamber. Therefore, a cross-calibration is needed between the scanner and the dose-calibrator. Despite this use of cross-calibration, SUV is still only a semi-quantitative parameter indicative of regional uptake, reliant on several biological assumptions, and therefore subject to several sources of error. As a result, SUV is useful to illustrate change in an individual’s tracer uptake for multiple scans, but it has more limited value in comparing across individuals where the assumptions may not be valid. A further parameter commonly used in neurological analysis is the ratio of SUV values for a tissue of interest and a reference tissue. This is normally referred to as the SUV ratio (SUVR), but this in effect is simply the ratio of reconstructed tissue values and requires no cross-calibration (injected dose and patient weight cancel in the ratio). It is therefore identical to the semi-quantitative indices mentioned earlier. To call it SUVR is misleading as it implies that it is somehow related to SUV, when it is not.
Control of Movement and Posture
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The energy expended in walking along a horizontal path (level walking) varies quadratically with speed, up to about 100 m/min (6.6 km/hr) (Ralston, 1976) (see Problem 13.3). This energy seems to be essentially gender-independent when expressed per kg of body weight, particularly if based on lean body weight. Interestingly, humans seem to adjust step length and stepping rate for minimal energy expenditure per unit distance (Problem 13.4).
Lifestyle Approaches Targeting Obesity to Reduce Cancer Risk, Progression, and Recurrence
Published in James M. Rippe, Lifestyle Medicine, 2019
Debora S. Bruno, Nathan A. Berger
A body mass index between 18.5 and 24.9 is considered healthy as it is associated with decreased risk for developing many diseases, such as type 2 diabetes mellitus, hypertension, coronary artery disease, strokes, and, of course, many cancers.4–6 As previously noted, individuals should strive to achieve and keep a lean body weight throughout life, including throughout childhood and old age, since increased weight at any time of life may result in obesity at later stages and may also have long-lasting epigenetic effects. In a recent meta-analysis of 50 prospective studies, adult weight gain was significantly associated with increased risk for post-menopausal breast cancer, endometrial and ovarian cancers, as well as colon cancer in men.92 In adolescents, overweight and obesity have been associated with increased risk for colon cancer93 and colon cancer-related death.94 And even though the incidence of colon cancer has decreased overall since the late 1990s, colon and rectal cancer rates have actually increased by 90% and 124% respectively for patients ages 20 to 34.95
An update on the safety of prescribing opioids in pediatrics
Published in Expert Opinion on Drug Safety, 2019
Jagroop M. Parikh, Patricia Amolenda, Joseph Rutledge, Alexandra Szabova, Vidya Chidambaran
The prevalence of OSA in children is 1–4% [54], with a higher prevalence of severe obesity [55]. In severe OSA, there is an upregulation of μ-opioid receptors due to recurrent hypoxemia [56]. Thus, administration of opioids and concomitant sedatives increases the risk for respiratory depression, increased pharyngeal collapse, and exacerbation of obstructive symptoms in these situations. Dosing considerations for opioids in obese children require consideration of opioid pharmacokinetics and dosing weights. Lean body weight (LBW) is the most appropriate dosing scale to use especially that their cardiac output is significantly correlated to LBW. Multimodal analgesia with non-opioid analgesics and regional techniques is preferred to reduce the opioid use in these patients [57]. ‘PK mass,’ which is correlated to lean body mass, has also been proposed as a scalar for dosing patients spanning weights of 40–210 kg, as it correlated linearly with fentanyl doses needed to maintain analgesia [58]. It is especially prudent to cautiously titrate opioids in these patients. Similarly, special precautions are also given to patients with known difficult airway or at risk of upper airway obstruction (e.g. facial and neck edema). Opioids and other sedating medications should be cautiously given due to risk of apnea and desaturation. Vigilant monitoring is critical. A multimodal approach to pain control is preferred to decrease opioid use. Whenever possible, local infiltration and peripheral nerve blocks be considered in these patients.
Association between sarcopenia and erectile dysfunction in males with type II diabetes mellitus
Published in The Aging Male, 2019
Sema Uçak, Rıdvan Sivritepe, Oğuzhan Kara, Ecem Sevim, Damla Ortaboz, Eyüp Veli Küçük, Sabri Atay, Arzu Çalışgan Baygül
Weight, muscle mass (%), body fat percentage (%), metabolism/body fat, and lean body weight were measured using bioelectrical impedance analysis (BIA). BIA was performed using a bioelectrical impedance analyzer which is a single frequency BIA system (50 kHz) with eight-point contact electrodes and two stainless-steel rectangular foot pad electrodes, which are fastened to a metal platform set on force transducers for measurement of weight (BC-418MA, Tanita Corp.). Four separate foot-pad electrodes are mounted onto the base and two electrodes are mounted in each of the hand grips. This BIA system can estimate body composition in either “standard” or “athlete” mode. In the present study, body composition assessment was conducted in “standard mode”. Full body skeletal muscle mass (SMM) and SMM index (SMMI) were used as indicators of sarcopenia.
Development and Prospective Federal State-Wide Evaluation of a Device for Height-Based Dose Recommendations in Prehospital Pediatric Emergencies: A Simple Tool to Prevent Most Severe Drug Errors
Published in Prehospital Emergency Care, 2018
Jost Kaufmann, Bernhard Roth, Thomas Engelhardt, Alex Lechleuthner, Michael Laschat, Christoph Hadamitzky, Frank Wappler, Martin Hellmich
The beneficial impact of simple measures on life-threatening errors was repeatedly shown in simulated scenarios. These include simple weight based tables that provide dose recommendations. This prevented 90% of tenfold errors when compared to not using this tabular aid.24 Nevertheless, length-based devices are superior to other dose recommendation sources due to their greater abilities. First of all, they offer a better weight estimation method than age-related estimation12 and provide the average weight for a certain height, which is correlating closely to the lean body weight25 and the extracellular fluid compartment for the volume of distribution for hydrophilic drugs.26 The reliability and feasibility of this weight-estimation method was proven for the preclinical setting.27 The knowledge of age-related physiological values is also essential to guide resuscitation28 and was included in the PaedER. It was grouped together with all other length-based recommendations negating the need to look them up in emergency situations.