沉痛悼念我国著名辐射防护专家潘自强院士(1936—2022)

中国工程院院士、中国核工业功勋奖章获得者、辐射防护和环境保护著名专家、中国辐射防护学会荣誉理事长、《中华放射医学与防护杂志》第八至十届编辑委员会顾问、 Radiation Medicine and Protection共同荣誉主编潘自强研究员因病医治无效,于2022年1月19日13时18分在北京逝世,享年85...     

体表覆盖干燥棉织物对放疗剂量的影响

放射治疗时,由于体位固定及体表标注摆位中心三维坐标的需要,患者通常需要裸露身体某一部位进行治疗,而直线加速器对治疗室温度有要求(一般25℃左右),肿瘤患者大多年老体弱免疫力低下,在此温度条件下常感觉体凉,严重者出现发热、咳嗽等症状而影响治疗的正常进行。最简便的方法就是在患者身上盖薄毯或棉被等干燥棉织物,然而,体表覆盖干...     

《中华放射医学与防护杂志》创办者之一姚家祥(1922—2021)

《中华放射医学与防护杂志》的创办者之一、中国疾控中心辐射安全所姚家祥研究员因病医治无效,于2021年12月23日上午7点40分逝世,享年100岁。     

The effects of 72 h of dynamic ankle immobilization on neural excitability and lower extremity kinematics

BackgroundAnkle injuries can foster maladaptive changes in nervous system function that predisposes patients to subsequent injury. Patients are often placed in a dynamic boot immobilizer (BI) following injury; however, little is known about the effects of this treatment on neuromechanical function.Research questionWe aimed to determine the effect of 72 h of BI-use on neural excitability and lower extremity joint motion in a healthy cohort.MethodsTwelve uninjured individuals (20.8 ± 1.4 yrs, 1.7 ± 0.1 m, 75.2 ± 9.9 kg) participated in this crossover study. Neural excitability and lower extremity kinematics were assessed before and after 72 h of BI or compression sock (CS) use. Neural excitability was assessed via the Hoffmann (H) reflex and transcranial magnetic stimulation of the motor cortex by measuring muscle activation at the tibialis anterior, peroneus longus, and soleus of the immobilized extremity. Three-dimensional lower extremity joint angles were assessed while participants walked on a treadmill. Repeated-measures analyses of variance detected changes in neural excitability and peak joint angles across time-points and testing conditions, while statistical parametric mapping (SPM) was implemented to determine continuous joint angle changes (α = 0.05).ResultsPre-BI to post-BI, H_Max:M_Max ratio (F = 6.496; p = 0.031) significantly decreased. The BI did not alter resting motor threshold (F = 0.601; p = 0.468), or motor evoked potential amplitudes (F > 2.82; p > 0.608). Significant changes in peak knee and hip angles in the frontal and transverse planes were observed (p < 0.05), with no changes at the ankle. SPM analyses revealed significant hip and knee changes in range of motion (p < 0.05).SignificanceDecreased measures of reflex but not corticospinal excitability suggest that BI-use for 72 h unloaded the joint enough to generate peripheral changes, but not the CNS, as has been described in casting models. Further, kinematic changes were observed in proximal lower extremity joints, likely due to swing-phase adaptations while wearing the BI.     

Discontinuation of metformin to prevent metformin-induced high colonic FDG uptake: is 48 h sufficient?

Annals of Nuclear Medicine - In this retrospective, single-center observational study, we investigated whether discontinuing metformin for at least 48&nbsp;h prevents metformin-induced...     

A pilot study to investigate the effect of a hydration regime upon immediate and 24 h delayed MRI contrast agent reactions

PurposeAdverse reaction rates to gadolinium based magnetic resonance imaging (MRI) contrast agents which occur immediately post-injection are well documented. However little research has investigated delayed reaction rates (i.e. 30 min–24 h). This study evaluated the rate of immediate and delayed adverse reaction rates to a gadolinium based MRI contrast agent (Dotarem^®) and investigated the effect of a hydration regime on the rate of adverse events.MethodFifty-eight patients received no preparation, prior to administration of the contrast agent, whilst another 58 underwent a hydration protocol. The patients had their answers to a questionnaire recorded immediately after the scanning procedure and also via a follow-up telephone call 24 h later.ResultsIn the unprepared group 9 patients (15.5%) experienced immediate adverse events, i.e. within 0–30 min, whereas 24 (41.4%) experienced delayed reactions (30 min–24 h) after administration of the contrast agent. In the hydrated patient group 6 (10.3%) experienced an immediate adverse event, whilst 8 (13.7%) experienced delayed events post-injection. The difference in the total reaction rates for the unprepared and hydrated groups was statistically significant for immediate and delayed reactions. The difference in the rates of delayed headache, nausea, dizziness and problems with the injection site, for the unprepared and hydrated groups was statistically significant.ConclusionAn oral hydration regime administered to patients, both before and after MRI contrast agent administration significantly reduced the total number of immediate and delayed reactions. It also significantly reduced delayed headache, nausea, dizziness and problems at the injection site. Whilst this pilot study had methodological shortcomings, the strength of the relationship demonstrated are worthy of further investigation.     

Evaluation of MR safety of a set of canine ear defenders (MuttMuffs®) at 1 T

Previous studies have indicated that loud noise produced during MR scanning is hazardous for human patients. Although loud noise can also be harmful to canine patients in MRI, ear protection is not routinely provided. The purpose of this study was to test the safety of a set of commercially available canine ear defenders (MuttMuffs^®) during MRI scanning at 1 T. A metal fastening ring was removed and replaced with a plastic washer prior to testing. Torque, translation, heating and artifact production were tested. No torque, translation, or excessive heating were detected. No artifacts were observed. Clinical use demonstrated additional benefits of improved immobilisation of the dog, with no effect on signal-to-noise ratio. Results from this study indicate that following replacement of the metal ring with one made of plastic, these canine ear defenders are suitable for use at 1 T. The author recommends the use of ear defenders during canine MRI scans in order to reduce the risk of hearing damage, reduce the dose needed for anaesthetic maintenance and reduce the need for repeated MRI sequences due to movement of the dog.     

Endorectal magnetic resonance imaging for predicting pathologic T3 disease in Gleason score 7 prostate cancer: Implications for prostate brachytherapy

PurposeTo determine the ability of endorectal magnetic resonance imaging (erMRI) and other pretreatment factors to predict the presence and extent of extraprostatic extension (EPE) in men with Gleason score (GS) 7 prostate cancer.Methods and MaterialsWe included patients with clinical stage T1c–T2c, GS = 7 (3 + 4 or 4 + 3), and prostate-specific antigen (PSA) <10 ng/mL who underwent pre-prostatectomy erMRI. We compared pathologic EPE findings with pretreatment factors.ResultsOne hundred seventy-one men were eligible for inclusion. Pretreatment characteristics were: median age = 60 years (42–76); median PSA 4.9 ng/mL (0.4–9.9); GS 3 + 4 = 61%; T1c = 51%; T2a = 25%; T2b = 21%; T2c = 3%; ≥50% positive cores = 46%; EPE-positive (EPE+) erMRI = 28%. Thirty-three percent had pathologic EPE. Increasing T-stage (p < 0.0001) and EPE+ erMRI (p < 0.0001) were significant predictors of pathologic EPE, whereas GS (4 + 3 vs. 3 + 4) (p = 0.14), percentage of positive core biopsies (p = 0.15), and pretreatment PSA (p = 0.41) were not. Median EPE distance was 1.75 mm (range, <1–15 mm). The rates of EPE >5 mm and EPE >3 mm were 11% and 15%, respectively. The odds ratios for erMRI detection of any EPE and of EPE >5 mm were 3.06 and 3.75, respectively.ConclusionsT-stage and EPE+ erMRI predict pathologic EPE in men with GS 7 prostate cancer. The ability of erMRI to detect EPE increases with increasing EPE distance. These findings may be useful in patient selection for prostate brachytherapy monotherapy.     

Cardiorespiratory fitness in 16 025 adults aged 18–91 years and associations with physical activity and sitting time

Our aim was to provide up‐to‐date cardiorespiratory fitness reference data for adults of all ages and to investigate associations between cardiores‐piratory fitness and leisure time physical activity as well as sitting time. In the Danish Health Examination Survey 2007–2008, cardiorespiratory fitness was estimated in 16 025 individuals aged 18–91 years from validated cycle ergometer exercise tests. Level of leisure time physical activity (sedentary, light, moderate, and vigorous) and daily sitting time in hours was obtained from a self‐administered questionnaire. Men had 20–33% higher cardiorespiratory fitness than women, depending on age, and cardiorespiratory fitness decreased by 0.26 and 0.23 mL/min/kg per year in men and women, respectively. Cardiorespiratory fitness was higher among participants who reported a high level of physical activity in leisure time compared with participants who were sedentary. Among sedentary or lightly physically active participants, inverse associations between total daily sitting time and cardiorespiratory fitness were found, while there was no association between sitting time and cardiorespiratory fitness among moderately or vigorously physically active participants. These data on cardiorespiratory fitness can serve as useful reference material. Although reluctant to conclude on causality, sitting time might impact cardiorespiratory fitness among individuals with low levels of leisure time physical activity.     

Le passage de la posture classique à la posture en danseuse par le cycliste répond-il à une recherche de minimisation de l'effort musculaire ?

The subject of this study was to examine if the cyclist chose their propulsion position to minimise their muscular activity. The muscular efforts have been estimated by the calculation of the joints moments using the inverse dynamics. Eight adult subjects have participated in this study. Each subject has to pedal using classical position and dancer position at five different powers. The results show that at low power (around 100 W) the joints moments are sensibly the same between classic and dancer position. But when their output power increases, joints moments using dancer position were significantly inferior in dancer as opposed to classic position. The Discussion suggests that when cyclists pedal at high power, using dancer position make the cyclist able to minimize his muscular efforts.