Age-dependent thyroid absorbed doses for radiobiologically significant radioisotopes of iodine

In light of the post-Chernobyl increase in pediatric thyroid cancer incidence, among other recent events, there is renewed interest in radioiodine thyroid dosimetry and effects. Among the radioiodines produced in fission of 235U, only 131I [(T1/2)p = 8.04 d], 132I (2.3 h), 133I (20.3 h), and 135I (6.7 h) may undergo significant environmental dispersion. Age-dependent thyroid absorbed dose estimates for these radiobiologically significant radioiodines and for the "medical" radioisotopes 123I (13.2 h) and 125I (60 d) have been derived, incorporating the effect of absorption following inhalation or ingestion. This effect has generally been ignored in previously derived estimates of radioiodine absorbed doses to the thyroid. Based on the latest ICRP lung and gut models, inhaled radioiodine is absorbed at a rate of 0.175 h(-1) and exhaled at 0.101 to 0.118 h(-1) (depending on age) and ingested radioiodine is completely absorbed in the stomach at a rate of 1 h(-1). Whole-body compartmental models (SAAM II) were fit to previously published 24-h thyroid uptakes, thyroid half-times, and 48-h plasma concentration of protein-bound iodine. The resulting fitted models were used to calculate thyroid residence times of radioiodine. The mean thyroid absorbed doses [cGy/37 kBq (rad/microCi) injected intravenously] were then calculated using the age-dependent S(thyroid<--thyroid) factors (MIRDOSE III), with the highest doses (from 0.49 for 123I to 36 for 131I) in newborns and the lowest doses (from 0.014 for 123I to 1.4 for 131I) in adults in inverse relation to the thyroid mass. Although the thyroid absorbed dose for inhalation is substantially (30 to 70%) less than that for injection for all radioiodines and at all ages, it is markedly (25%) less for ingestion only for short-lived 132I.     

Dialysis modality selection among patients attending freestanding dialysis facilities

Persons with end stage renal disease (ESRD) are eligible to receive dialysis services under the Medicare program. An individual-level analysis was performed to determine the factors associated with the modality selected by patients; namely in-center hemodialysis, continuous ambulatory peritoneal dialysis (CAPD), continuous cycling peritoneal dialysis (CCPD), and home hemodialysis. Logistic regression equations were estimated using program data for 73,448 ESRD Medicare patients attending freestanding dialysis facilities. The results showed that CAPD, CCPD, and home hemodialysis were more likely to be selected by patients who were younger, had non-systemic precipitating causes of ESRD, had a shorter duration of ESRD, attended larger facilities, and were not ethnic minorities. There is no consistent evidence demonstrating the superiority of particular modalities. The policy goal should be to enable beneficiaries to use the modality for which they are best suited, which requires that the range of modalities be available to all ESRD beneficiaries.     

Dialysis for end-stage renal disease. Determining a cost-effective approach

OBJECTIVE: Renal replacement therapy (RRT) is essential for maintenance of life for those with end-stage renal disease. However, there remain many areas of uncertainty about which method of RRT should be chosen. This paper reports an economic model based on a systematic review that attempts to determine which method of dialysis, continuous ambulatory peritoneal dialysis (CAPD) or hemodialysis, a patient should have as the initial method of RRT. METHODS: A systematic review and a costing exercise carried out in a Scottish hospital were used to populate a Markov model. Scenario analysis was used to model plausible variations in variables included in the model. RESULTS: In 8 of the 16 scenarios developed hemodialysis dominated CAPD. In a further eight scenarios, the cost per life-year displayed considerable variability, ranging from between 5,000 Pounds to 51,000 Pounds. The higher costs per life-year were associated with minimum estimates of additional survival for a patient starting RRT on hospital hemodialysis. CONCLUSION: It may be more cost-effective to manage patients starting on RRT with hospital hemodialysis than CAPD. This has particular implications for the United Kingdom, given that up to 50% of new patients receive CAPD.     

Uncertainties in dose coefficients from ingestion of 131I, 137Cs, and 90Sr

Quantification of uncertainties in doses from intakes of radionuclides is important in risk assessments and epidemiologic studies of individuals exposed to radiation. In this study, the uncertainties in the doses per unit intake (i.e., dose coefficients) for ingestion of 131I, 137Cs, and 90Sr by healthy individuals have been determined. Age-dependent thyroid dose coefficients were derived for 131I. The analysis for 131I uses recent measurements of thyroid volume obtained by ultrasonography, which indicate a thyroid mass lower than that previously obtained using autopsy measurements. The coefficients for 137Cs are determined using the relationship between the biological half-lives and the amount of potassium in the human body. The most recent International Commission on Radiological Protection biokinetic model was employed to determine the uncertainties for 90Sr. For 137Cs and 90Sr, the dose coefficients represent exposure in adulthood and they were determined for all organs of radiological importance. The uncertainty in the estimated dose coefficients represent state of knowledge estimates for a reference individual, and they are described by lognormal distributions with a specified geometric mean (GM) and geometric standard deviation (GSD). The estimated geometric means vary only slightly from the dose coefficients reported by ICRP publications. The largest uncertainty is observed in the dose coefficients for bone surface (GSD = 2.6), and red bone marrow (GSD = 2.4) in the case of ingestion of 90Sr. For most other organs, the uncertainty in the 90Sr dose coefficients is characterized by a GSD of 1.8 (or less for some organs). For 131I, the uncertainty in the thyroid dose coefficients is well represented by a GSD of 1.7 for both sexes and all ages other than infants for whom a GSD of 1.8 is more appropriate. The lowest uncertainties are obtained for the dose coefficients from ingestion of 137Cs (GSD = 1.24 for males; 1.4 for females). A dominant source of uncertainty in the ingestion dose coefficients is the variation of the biokinetic parameters. For 131I, the largest contribution to the uncertainty comes from the variation in the thyroid mass, but the contribution of the biokinetic parameters is comparable. The biokinetic parameters with the largest contribution to the uncertainty are (a) the fractional uptake from blood to thyroid in the case of ingestion of 131I, (b) the absorbed fraction from the gastrointestinal tract (f1) in the case of 90Sr, and (c) the amount of potassium in the body for 137Cs. The contribution to the uncertainty of the absorbed fraction (which accounts for the fraction of energy deposited in the target organ) is the smallest contributor to the uncertainty in the dose coefficients for most organs. To reduce the uncertainty in the dose estimated for a real individual, one should determine the above-mentioned parameters for the specified individual rather than to rely on assumptions for a reference individual.     

Terminal kidney insufficiency in children in the years 1979 through 1986 in The Netherlands

During the period 1979-1986, 167 children with terminal renal failure were treated in 4 dialysis centres for children: 124 of them were treated by haemodialysis, 43 by continuous ambulatory peritoneal dialysis (CAPD). The frequency of CAPD increased during the last few years. This method is suitable for small children. The number of transplantations should be increased. Present facilities cannot deal with the numbers of new patients with terminal renal failure.     

大剂量重组人促红细胞生成素治疗慢性肾衰竭贫血的效果及机制

目的：研究和探讨大剂量重组人促红细胞生成素用于慢性肾衰竭（CRF）贫血的临床治疗效果及治疗机制。方法：选取本院2012年3月-2014年3月收治的慢性肾衰竭贫血患者58例,所有患者均予以1.2万IU rHuEPO皮下注射,每周1次,共治疗8周。患者每日服用维铁缓释片1粒,并常规运用维生素B12和叶酸。检测患者的骨髓象、血象、SI、SF及铁粒幼细胞计数。结果：58例患者中显效28例,有效26例,无效4例,总有效率为93.1%。用药2周后患者的Ret、RBC、Hb、Hct开始升高,用药8周后血象红系各指标较用药前有显著升高,差异均有统计学意义（P〈0.01）。患者骨髓红系增生较治疗前而言活跃显著,且早幼红、中幼红、晚幼红和E值较用药前有显著升高,其中晚幼红增生最显著,故G/E值较用药前显著降低,经治疗8周后患者SI、SF及铁粒幼细胞值均显著降低,差异均有统计学意义（P〈0.05）。结论：大剂量重组人促红细胞生成素可有效用于慢性肾衰竭贫血患者的临床治疗,通过刺激骨髓造血的机理恢复机体的正常造血功能,在慢性肾衰竭贫血患者的临床治疗上具有广泛的发展前景。     

A comparison of taste acuity for salt in renal patients vs. normal subjects

In this pilot study, 30 patients with renal disease receiving renal replacement therapy (10 each in the following groups: continuous ambulatory peritoneal dialysis [CAPD] patients, hemodialysis [HD] patients, and renal transplant recipients) and 10 control subjects were given salt solutions of varying concentrations (0 to 600 mmol/L) and asked to rate them subjectively according to their perceived taste intensity. The mean age in each of the four groups ranged from 31.9 to 34.1 years. No significant differences were found in the ratings of perceived salt intensity among patients and control subjects. On the basis of 3-day food records plus recall of seasonings used, mean intake of sodium was estimated to be higher in CAPD patients and control subjects than in HD and transplant patients (p less than 0.02). Patients on CAPD stated a preference for salty items, whereas control subjects preferred the less salty items despite similar estimated sodium intakes. It thus appears that the ability to perceive various salt tastes may not be impaired in patients on renal replacement therapy. In addition, inappropriate salt intake commonly seen in those patients may be due to increased salt appetite, specifically in those patients managed by CAPD.     

Provision of home dialysis by freestanding renal dialysis facilities

This article explores home dialysis provision among freestanding renal facilities by examining whether they provide continuous ambulatory peritoneal dialysis (CAPD), continuous cycling peritoneal dialysis (CCPD), and home hemodialysis. These modalities require fewer visits to a dialysis center, which may be beneficial for patients living long distances from facilities. A negative association was found between the number of facilities per square mile and the probability of provision of the home modalities. Secondly, facilities with a higher percent of black patients were less likely to provide the home modalities. Thirdly, facilities with larger numbers of patients were more likely to provide the home modalities.     

Dose absorbed by mouse red bone marrow after oral administration of tritiated water

Tritiated water (HTO) was given to mice orally. Dose accumulation patterns in various organs and tissues after oral HTO intake were compared with those after intraperitoneal injection. The accumulated dose was 10-20% higher after intraperitoneal injection than after oral administration. A new technique was developed to isolate mouse red bone marrow from tibia. The absorbed beta-ray dose in the red bone marrow after oral tritium intake was lower than the body-averaged dose that was estimated based on the tritium concentration in the urine or the blood and higher than the absorbed dose in the liver and testis.     

Increased resting energy expenditure in patients with end-stage renal disease

BACKGROUND: Protein-calorie malnutrition is a significant problem for patients with end-stage renal disease. Increased resting energy expenditure may be an important contributing factor. We postulate that resting energy expen diture in the different stages of renal disease and treatments may be different. METHODS: Resting energy expenditure was measured using a whole-room indirect calorimeter (metabolic chamber) along with nutritional parameters and body composition after 12-hour fasting in 15 patients with advanced chronic renal failure patients, 15 patients on chronic hemodialysis, and 10 patients on peritoneal dialysis. Patients on hemodialysis were assessed on a non-dialysis day. A 2-day dietary recall was used to assess energy intake. RESULTS: Resting energy expenditure, adjusted for fat-free mass, was similar in patients on hemodialysis and peritoneal dialysis but significantly higher than in patients with chronic renal failure (p < .05). Resting energy expenditure in all patients were generally higher (10% to 20%) than predicted values using standard equations derived in normal and obese populations, whereas daily energy intake was less (26% to 34%) than energy expenditure for all groups, adjusted for light daily activity. CONCLUSIONS: End-stage renal disease patients displayed increases in resting energy expenditure over the predicted values derived using normal populations. Resting energy expenditure was significantly higher in patients receiving dialysis, regardless of the modality, than patients with chronic renal failure. Daily energy intake was substantially less than required in all patient groups studied, suggesting that patients with renal failure could develop protein-calorie malnutrition because of increased resting energy expenditure, which is exacerbated by dialysis.     

慢性肾功能衰竭患者的凝血纤溶功能紊乱

目的 :观察尿毒症未透析组 (CRF)、血透 (HD)、腹透 (CAPD)治疗组凝血、纤溶功能的变化。方法 :采用ELISA方法检测 12例HD、CRF、CAPD各 10例患者的凝血、纤溶参数TAT(凝血酶 -抗凝血酶Ⅲ复合物 )、PAP(纤溶酶 -α2 抗纤溶酶复合物 )、D -二聚体的水平 ,并与 10例健康者对照。结果 :所有尿毒症患者TAT、D -二聚体均显著升高 ,CAPD组升高最为显著 ,HD与CRF组无显著差异。PAP各组也高于正常对照组 ,但CRF、HD组值基本在正常范围内 ,CAPD组显著升高。结论 :慢性肾功能衰竭普遍存在高凝状态 ,腹膜透析引起的高凝状态最为明显 ,同时患者也存在继发的纤溶功能紊乱。     

Cost-effectiveness of interventions for end-stage renal disease]

OBJECTIVE: The study reports the cost-effectiveness results of end-stage renal disease (ESDR) patients in Mexico in terms of years of life gained and quality of life and the economic cost with regards to three treatment alternatives that could be considered mutually exclusive: continuous peritoneal ambulatory dialysis (CAPD), hemodialysis (HD) and renal transplant (RT). METHOD: The economic costs were calculated by using the average cost case-management methodology and further, the probable of life expectancy and the quality of life were cross-sectionally assessed by means of the Quality Adjusted Life Years (QALY) measured by the Rosser Index. RESULTS: The results show that economic costs in US$ of the three treatment alternatives were: CAPD $5,643.07, HD $9,631.60, and RT $3,021.63. The probability of life expectancy for CAPD and RT for the first and third year were: 86.2% and 66.9%, and 89.9% and 79.6%, respectively. The QALY scores for patients were: CAPD 0.8794, HD 0.8640, and RT 0.9783. CONCLUSION: The intervention with the highest cost-effectiveness coefficient was the renal transplant (3,088.69), followed by the CAPD (6,416.95) and HD (11,147.68). A significant difference was found between the transplanted patients and patients undergoing dialysis. Finally, this study concluded that the RT offers the least expensive alternative and the greatest number of years of life gained as well as providing significant changes in the quality of life of ESRD patients.     

Serum levels of vitamin A and retinol binding protein in chronic renal patients treated by continuous ambulatorial peritoneal dialysis.

The possible causes and consequences of hypervitaminosis A and retinol binding protein (RBP) levels were investigated in patients with chronic renal disease submitted or not to dialysis treatment. The study was conducted on 20 patients divided into two groups: 10 patients with chronic renal failure (CRF) treated by continuous ambulatorial peritoneal dialysis (CAPD), and 10 CRF patients with no dialysis treatment. Ten normal subjects formed the control group. Retinol levels were determined by HPLC, and RBP levels by immunoassay in plasma and in post-dialysis fluid at different periods of time. Laboratory tests were carried out on all subjects, and dietary history was taken. Patients on dialysis had higher retinol levels than untreated patients. Retinol levels were found to be correlated with RBP levels. Serum retinol and RBP levels did not vary with diet, age or time of disease, dialysis group or time of dialysis, nor were they correlated with the levels measured in the dialysis fluid (CAPD). There was no significant correlation in retinol levels between chronic patients and controls. It is suggested that vitamin A and RBP clearances during dialysis do not accompany urea or creatinine clearance. Hypervitaminosis A did not show any toxic effect.     

223Ra使用过程中的辐射安全评估

²²³Ra（氯化镭[²²³Ra]注射液,多菲戈^®）是全球首个α粒子靶向治疗药物,用于治疗伴症状性骨转移且无已知内脏转移的去势抵抗前列腺癌患者。本文综述了氯化镭[²²³Ra]注射液使用过程中的辐射安全评估,包括医护人员操作²²³Ra过程中的辐射安全、患者注射²²³Ra后的辐射安全以及患者注射²²³Ra后对家庭成员和公众人员的辐射影响。医护人员手部每次注射接受的有效剂量约为41 μSv,²¹⁹Rn引起的有效剂量约为3.5 μSv;患者注射²²³Ra后骨内膜和红骨髓是吸收剂量最高的组织,α粒子引起的吸收剂量分别为7.5×10⁻⁷ Gy/Bq和7.2×10⁻⁸ Gy/Bq;完成药物注射时,直接接触患者的平均辐射剂量率小于2 μSv h⁻¹ MBq⁻¹,距患者1 m处的平均辐射剂量率约为0.02 μSv h⁻¹ MBq⁻¹。患者注射药物后无需因放射性在医院特殊停留。     

Electron absorbed fractions and dose conversion factors for marrow and bone by skeletal regions

The possible inductions of bone cancer and leukemia are the two health effects of primary concern in the irradiation of the skeleton. The relevant target tissues to consider in the dosimetric evaluation have been the cells on or near endosteal surfaces of bone, from which osteosarcomas are thought to arise, and hematopoietic bone marrow, which is associated with leukemia. The complex geometry of the soft tissue-bone intermixture makes calculations of absorbed doses to these target regions a difficult problem. In the case of photon or neutron radiations, charged particle equilibrium may not exist in the vicinity of a soft tissue-bone mineral interface. In this paper, absorbed fraction data are developed for calculations of the dose in the target tissues from electron emitters deposited within the volume or on the surfaces of trabecular bone. The skeletal average absorbed fractions presented are consistent with usage of this quantity in the contemporary dosimetric formulations of the International Commission on Radiological Protection (ICRP). Implementation of the new bone and marrow model is then developed within the context of the calculational schema of the Medical Internal Radiation Dose (MIRD) Committee. Model parameters relevant to the calculation of dose conversion factors (S values) for different regions of the skeleton of individuals of various age are described, and an example calculation is performed for a monoclonal antibody which localizes in the marrow. The utility of these calculations for radiation dose calculations in nuclear medicine is discussed.     

服用不同剂量的~(131)I治疗甲状腺癌后辐射剂量率的测定

目的了解甲状腺癌患者服用不同剂量的131I治疗后辐射剂量率的变化及意义。方法对32例服用131I〔剂量3.7～7.4Bq(100～200mCi)〕治疗的甲状腺癌患者进行1和2m距离不同时间的辐射剂量率的测定,连测6d。结果不同剂量的辐射剂量率在服药后1h均达到高峰,随后下降,剂量越大下降越快。2m距离的辐射剂量率较1m距离明显偏低(P0.01),下降曲线相似。1m距离第6天、2m距离第5天不同剂量的辐射剂量率与本底相比,差异无统计学意义(P0.05)。结论甲状腺癌患者服用不同剂量的131I后,辐射剂量率的升高和下降与剂量有明显关系,但随时间延长辐射剂量率均逐渐减少,至第五六天与本底值已无差异。     

Retarded motor and cognitive development of young children with severe kidney disorders]

OBJECTIVE. Medical and technical advances make it possible to treat young children with end-stage renal disease with far-reaching methods such as continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis (HD). We investigated whether chronic renal failure has deleterious effects on motor function and cognitive development. SETTING. The pediatric dialysis centres of the university hospitals of Nijmegen, Utrecht and Rotterdam. DESIGN. Prospective study. METHODS. 18 patients (mean age 37 months) with chronic renal failure since infancy and 18 healthy children (mean age 35 months) as controls were assessed on cognitive and behavioural parameters. Nine patients and 17 control subjects were tested on their motor function. RESULTS. A significant delay (more than one SD) was found in the motor as well as in the cognitive development of the patient group. Within this group a large difference was noticed between patients under conservative treatment (n = 8; mean dev. index 92.0) and those under CAPD or HD treatment (n = 10; mean dev. index 72.4). CONCLUSION. Young dialysis patients are evidently at risk for developmental retardation. Monitoring this vulnerable group by developmental screening and intensive counselling of the parents is strongly recommended.     

Cost-effectiveness analysis of the treatment of end-stage renal disease in Brazil

Cost-effectiveness analysis compared four treatments of end-stage renal disease in Brazil: continuous ambulatory peritoneal dialysis (CAPD), in-center hemodialysis (HD), cadaver donor transplantation (CD-Tx), and living related donor transplantation (LR-Tx). After 2 years, the costs per year of survival were CAPD, $12,134; HD, $10,065; CD-Tx, $6,978; and LR-Tx, $3,022. The HD cost was lower than CAPD partially because of the reuse of hemodialyzers in Brazil. Although less cost-effective, both dialysis treatments yielded more years of survival after 2 years. This analysis reveals a trade-off between cost per year of survival and years of survival.     

Segmental bioelectrical impedance in patients with chronic renal failure

We studied changes in hydration by whole body and segmental (arm, leg and trunk)bioelectrical impedance analysis (BIN in patients with chronic renal failure (CRF) undergoing haemodialysis and continuous ambulatory peritoneal dialysis (CAPD). Mean (SD) fluid removal by haemodialysis of 1.38 (0.81) kg was overestimated by whole body BIA at 1.83 (1.13) I, P < 0.005. Peritoneal fluid drained from the CAPD patients of 1.88 (0.36) kg was underestimated by whole body BIA at 0.59 (0.35) I, P < 0.0001. Resistance and reactance significantly increased for the whole body and all segments (except trunk reactance) after haemodialysis. Drainage of CAPD fluid resulted in smaller increases in trunk resistance and whole body resistance. The increase in trunk resistance was less in CAPD than haemodialysis patients, even though the volume of fluid drained from the peritoneum in CAPD patients exceeded that removed from the whole body during haemodialysis. We conclude that whole body BIA does not estimate changes in body fluid with sufficient accuracy to be of use in clinical practice. Segmental impedance may be a potentially useful method for investigation of regional changes in body fluid, though is insensitive to changes within the peritoneal cavity.     

糖尿病肾病患者使用血液透析机透析的时机观察

目的:探究糖尿病肾病患者使用血液透析机透析的时机。方法:回顾性分析本院2012年1月~2017年12月收治的42例行血液透析的糖尿病肾病患者的临床资料。其中,有24例患者在血肌酐达到707μmol/L时开始行长期血液透析(正常组),剩余18例患者透析前患者血肌酐在224~675uomL/L间,均因不同病情提前开始进行血液透析治疗(提前组)。结果:正常组中有13例患者死亡,剩余11例患者均已出现程度不一的血管病变情况,且均须通过血液透析机行长期透析。提前组中有2例死亡,4例须每周行2次长期透析,2例须每7~10d内行1次透析,有1例患者在出院1年后每周行1次血液透析,1例患者行肾移植,8例患者未再行透析治疗。结论:提前进行血液透析能够减缓糖尿病肾病进展至终末期肾功能衰竭的速度,并有效延长透析间隔时间,降低并发症发生率。