直线加速器全身照射技术

本文介绍了在直线加速器上实行全身照射的方法,包括治疗床的设计、测量装置的制作、实验参数的测定和照射方法。SSD＝450cm,机架角为270度,患者取侧卧位,前后野和后前野对穿照射,采用分段肺屏蔽办法控制肺的吸收剂量。用多通道半导体剂量仪进行剂量全程监测作为质量控制手段进行质量控制和实现质量保证,用入射表面剂量Din与出射表面剂量Daut之和的一半即（Din Dout)/2作为对应入射方向上体中层面的吸收剂量。     

肺屏蔽块对全身照射剂量分布的影响

目的：探讨全身照射（ＴＢＩ）中为控制肺剂量所采用肺屏蔽挡块对剂量分布的影响。方法：利用三维自动扫描水箱按实际ＴＢＩ照射条件测量三种厚度不同的肺铅挡块下，水模体中剂量分布情况。结果：加肺档块使纵膈区剂量减少，肺挡因子与测量的深度有关。结论：肺挡因子应在照射条件下测量。在全身照射总剂量与肺部限受剂量相差较大时，应注意纵膈剂量的修正。     

Oocyte donation in women cured of cancer with bone marrow transplantation including total body irradiation in adolescence

Female survivors of cancer in childhood and adolescence who have been treated with bone marrow transplantation including total body irradiation (TBI) are at high risk of developing ovarian follicular depletion and infertility. The lack of oocytes may be compensated for by oocyte donation but these patients also seem to have a uterine factor. Even though oestrogen replacement therapy is given, the growth of the uterus during adolescence is impaired. To our knowledge there have been no earlier reports of live births after oocyte donation in such patients. We report three cases of oocyte donation in women who, at a young age, were cured of haematological malignancies with bone marrow transplantation including TBI. In adolescence they developed ovarian failure and uterine volumes were assessed by ultrasonography. One woman with a uterus of almost normal size delivered a healthy child in the 37th week of gestation. Another woman with severely diminished uterine volume miscarried in the 17th week of gestation. The third woman has not yet conceived. Pregnancy achieved by oocyte donation is possible despite TBI in adolescence. However, the uterine factor is a concern and complications during pregnancy and preterm birth may be expected in these patients.     

Measurements of total body water with a foot-to-foot impedancemeter

The objective was to set-up a method for measuring total body water volumes (TBW) using a Tefal foot-to-foot impedancemeter (FFI) by comparison with a multifrequency medical impedancemeter and to validate this method against deuterium dilution data. The investigation was carried out in 57 Caucasian adult subjects. Impedancemeters were a Tefal Bodymaster Vision^® (foot-to-foot) featuring a square wave signal and a Xitron Hydra 4200^® (5–1000 kHz) using BIS method. TBW was measured by the Xitron using a new method that we have developed which applies the BIS method directly to extra and intracellular fluids combined. Although the high frequency impedance of the FFI (R_hf) was higher than the Xitron infinite frequency resistance and corresponded to a frequency around 100 kHz, TBW differences between the FFI and Xitron were not significant, 0.17 ± 2.17 L for men (P = 0.694) and 0.04 ± 1.88 L for women (P = 0.902). Then, our method was tested on another Caucasian population in which R_hf had been measured with the same FFI, together with TBW measurements by deuterium dilution. TBW differences between the FFI and dilution were −0.38 ± 2.27 L for men (P = 0.237) and −0.72 ± 2.37 L for women (P = 0.06).

Our method permits, at least in a Caucasian healthy population, to measure TBW using this FFI with the same accuracy as a whole body multifrequency medical impedancemeter, and the measurement, made in upright position, is much quicker.     

Determination of total body water by multifrequency bio-electric impedance: development of several models

Multifrequency bio-electronic impedance analysis (MF BIA) measurements are taken from a heterogeneous group of patients, varying in size between obese and slim. The measuring system uses four electrodes: two current and two potential electrodes. Three new models are developed to calculate total body water (TBW) from the BIA data, and the resulting TBW values are compared with TBW determined by D₂O dilution. The results demonstrate that the most simple model provides the best TBW values. For individual patients, TBW can be determined by means of bioimpedance measurement with an accuracy of 3 litres. In the most simple model (model 1), the body is electrically represented by a cylinder, and corrections are made for the amount of fat. This is an extension of the model used by Xitron. In the more advanced models (2 and 3), the body is represented by a cylinder for the trunk, and truncated cones represent the arms and legs. In model 2, ΔTBW amounts to 3 litres. It is shown that the resistance of the trunk is proportional to the square root of the length. In model 3, it is assumed that subcutaneous fat is a poor conductor if electric current. An equation is developed that describes the partition of subcutaneous fat, and the fat layer is then removed from the cones representing arms and legs and from the cylinder that models the trunk.     

Feasibility study of helical tomotherapy for total body or total marrow irradiation

Total body radiation (TBI) has been used for many years as a preconditioning agent before bone marrow transplantation. Many side effects still plague its use. We investigated the planning and delivery of total body irradiation (TBI) and selective total marrow irradiation (TMI) and a reduced radiation dose to sensitive structures using image-guided helical tomotherapy. To assess the feasibility of using helical tomotherapy, (A) we studied variations in pitch, field width, and modulation factor on total body and total marrow helical tomotherapy treatments. We varied these parameters to provide a uniform dose along with a treatment times similar to conventional TBI (15-30 min). (B) We also investigated limited (head, chest, and pelvis) megavoltage CT (MVCT) scanning for the dimensional pretreatment setup verification rather than total body MVCT scanning to shorten the overall treatment time per treatment fraction. (C) We placed thermoluminescent detectors (TLDs) inside a Rando phantom to measure the dose at seven anatomical sites, including the lungs. A simulated TBI treatment showed homogeneous dose coverage (+/-10%) to the whole body. Doses to the sensitive organs were reduced by 35%-70% of the target dose. TLD measurements on Rando showed an accurate dose delivery (+/-7%) to the target and critical organs. In the TMI study, the dose was delivered conformally to the bone marrow only. The TBI and TMI treatment delivery time was reduced (by 50%) by increasing the field width from 2.5 to 5.0 cm in the inferior-superior direction. A limited MVCT reduced the target localization time 60% compared to whole body MVCT. MVCT image-guided helical tomotherapy offers a novel method to deliver a precise, homogeneous radiation dose to the whole body target while reducing the dose significantly to all critical organs. A judicious selection of pitch, modulation factor, and field size is required to produce a homogeneous dose distribution along with an acceptable treatment time. In addition, conformal radiation to the bone marrow appears feasible in an external radiation treatment using image-guided helical tomotherapy.     

A comparison between total body thermosensitivity and local thermosensitivity in mammals and birds

We have investigated how total body thermosensitivity in various mammalian and avian species (mouse, rat, golden hamster, guinea pig, rabbit, dog, goat, pigeon, duck, goose) is related to their respective local thermosensitivities in the hypothalamus, spinal cord and skin. Local and total thermosensitivities were determined by measuring the relationship between the response of one thermoregulatory effector, metabolic heat production, and the appropriate temperature. Local cooling was performed with chronically implanted, water perfused thermodes, and local thermosensitivities were estimated by relating the maximum activation of metabolic heat production to the induced decreases in local temperature. Total body cooling was achieved by means of chronically implanted intravascular heat exchangers or with thermodes inserted into the lower intestinal tract, and total body thermosensitivity was assessed by relating the rise in metabolic heat production to the induced fall in core temperature. These analyses plus previous estimations derived from the literature show total body thermosensitivity in the different species to range from –4.0 to –12.0 W · kg^–1 · °C^–1. We also measured rabbit spinal cord thermosensitivity and guinea pig hypothalamic and spinal cord thermosensitivity; values for local thermosensitivity in other species were derived from the literature. In all species, local thermosensitivities determined as cold sensitivities in the described way were smaller than the corresponding total body core sensitivities. We conclude that thermosensitive structures outside of the investigated thermosensitive areas contribute a major input to the controller of body temperature, particularly in avian species in which hypothalamic thermosensitivity is lacking. This corresponds to observations in several mammalian and one avian species in which local and total body thermosensitivities were dervied from the responses of an autonomic heat defence effector, respiratory evaporative heat loss.     

Properties of a federated epidemiology query system

PURPOSE: The purpose of the study was to establish knowledge about how online access to epidemiological data from general practitioners (GPs) electronic health record (EHR) system should be provided. Before such systems are developed and deployed a decision about the appropriate system architecture must be made. Such a decision should ideally be based on knowledge about the properties of different system architectures. This choice is important because the system architecture may affect the willingness of GPs to participate in providing epidemiological data from their EHR system. METHOD: Verifying the performance and properties of an architectural approach by implementing and deploying a system on a trans-institutional level and performing evaluations studies is a very resource demanding method to establish a foundation for the decision of appropriate system architecture. Instead, we have tried to create this foundation by constructing a prototype system, establish knowledge about the properties of the system using experiments, and finally compare the properties of the federated approach to the properties of the centralised approach. By using this methodological approach we provide the best available knowledge, on this stage, for the appropriate system architecture to use for providing access to epidemiological data from the local population. RESULTS: Our experimental results show that it is possible to improve the timeliness and the temporal and spatial resolution of epidemiological data, compared to traditional centralised disease surveillance systems. Up-to-date epidemiological data from the local population may be provided directly from the source EHR system within 4s. The responsiveness of the system is minimally affected (0.1s) as the number of participating data providers grows from 1 to 49 data providers. The comparison of the federated approach to the centralised approach indicates that federated approaches avoid the privacy issues involved, as intended; it offers better scalability when computing speed is compared, and it provides better specificity because more data about the patient may be used. CONCLUSION: The conclusion from our study is that the federated approach to providing epidemiological data about the local population has many benefits over the traditional centralised approach. A federated approach to an epidemiology system may raise the GPs awareness of local disease outbreak because it is possible to share information about incidence rates of communicable diseases and use of laboratory requests in a geographical area that predates laboratory-based disease surveillance. The effects of the federated approach could be improved data quality in the EHR systems and improved representativeness of the epidemiological data for the areas covered by such systems.     

Comparative evaluation of brain neurometabolites and DTI indices following whole body and cranial irradiation: a magnetic resonance imaging and spectroscopy study

Understanding early differential response of brain during whole body radiation or cranial radiation exposure is of significant importance for better injury management during accidental or intentional exposure to ionizing radiation. We investigated the early microstructural and metabolic profiles using in vivo diffusion tensor imaging (DTI) and proton magnetic resonance spectroscopy (¹H MRS) following whole body and cranial radiation exposure of 8 Gy in mice using a 7.0 T animal MRI system and compared profiles with sham controls at days 1, 3, 5 and 10 post irradiation. A significant decrease in fractional anisotropy (FA) values was found in hippocampus, thalamic and hypothalamic regions (p < 0.05) in both whole body and cranial irradiated groups compared with controls, suggesting radiation induced reactive astrogliosis or neuroinflammatory response. In animals exposed to whole body radiation, FA was significantly decreased in some additional brain regions such as sensory motor cortex and corpus callosum in comparison with cranial irradiation groups and controls. Changes in FA were observed till day 10 post irradiation in both the groups. However, MRS study from hippocampus revealed changes only in the whole body radiation dose group. Significant reduction in the ratios of the metabolites myoinositol (mI, p = 0.02) and taurine (tau, p = 0.03) to total creatine were observed, and these metabolic alterations persisted till day 10 post irradiation. To the best of our knowledge this study has for the first time documented a comparative account of microstructural and metabolic aspects of whole body and cranial radiation induced early brain injury using in vivo MRI. Overall our findings suggest differential response at microstructure and metabolite levels following cranial or whole body radiation exposure. Copyright © 2013 John Wiley & Sons, Ltd.     

Consequences of prolonged total body immersion in cold water on muscle performance and EMG activity

The consequences of a prolonged total body immersion in cold water on the muscle function have not been documented yet, and they are the object of this French Navy research program. Ten elite divers were totally immerged and stayed immobile during 6 h in cold (18 and 10°C) water. We measured the maximal voluntary leg extension (maximal voluntary contraction, MVC) and evoked compound muscle potential (M wave) in vastus lateralis and soleus muscles at rest, after a submaximal (60% MVC) isometric extension allowing the measurement of the endurance time (Tlim). The power spectrum of surface electromyograms (EMG) was computed during 60% MVCs. MVCs and 60% MVC maneuvers were repeated four times during the immersion. Data were compared with those obtained in a control group studied in dry air condition during a 6-h session. Total body cooling did not affect MVC nor Tlim. The M wave duration increased in the coolest muscle (soleus), but only at 10°C at rest. There were no further fatigue-induced M wave alterations in both muscles. During 60% the MVCs, a time-dependant increase in the leftward shift of the EMG spectrum occurred at the two temperatures. These EMG changes were absent in the control group of subjects studied in dry air. The plasma lactate concentration was elevated throughout the 18 and mostly the 10°C immersion conditions. Throughout the 18°C immersion study, the resting potassium level did not significantly vary, whereas at 10°C, a significant potassium increase occurred soon and persisted throughout the study. Thus, total body immersion in cold water did not affect the global contractile properties of leg muscles during static efforts but elicited significant alterations in electromyographic events which may be related to the variations of interstitial fluid composition.     

3D打印个体化人工椎体在胸腰椎肿瘤整块切除后脊柱稳定性重建中的应用

目的探索3D打印个体化人工椎体在胸腰椎肿瘤整块切除后脊柱稳定性重建中的临床疗效。方法回顾性分析华中科技大学同济医学院附属同济医院2015年7月至2020年6月收治的接受一期后路全脊椎整块切除术的胸腰椎肿瘤患者28例,分为2组,每组14例。其中3D组使用3D打印个体化人工椎体重建,常规组使用钛笼重建。对比两组的住院时间、手术时间、术中出血量,记录术前、术后7 d及末次随访时视觉模拟评分(VAS),Frankel分级情况,测量节段高度及角度,评估临床疗效。结果两组患者住院时间、手术时间、术中出血量和VAS评分比较,差异无统计学意义。共8例患者Frankel评分获得一个等级的改善(28.6%)。3D组椎间高度丢失(1.9±2.2)mm,内植物沉降2例,沉降率14.3%;常规组椎间高度丢失(6.6±5.5)mm,内植物沉降8例,沉降率57.1%;两组比较差异有统计学意义(<0.05)。在节段角度丢失方面组间差异无统计学意义(=0.571)。3D组所有患者内固定良好,常规组1例患者发生断棒情况。结论 3D打印人工椎体可以更好地维持节段高度,降低椎间隙塌陷和内固定失败的风险。     

Intravenous Busulfan Compared with Total Body Irradiation Pretransplant Conditioning for Adults with Acute Lymphoblastic Leukemia

Total body irradiation (TBI) has been included in standard conditioning for acute lymphoblastic leukemia (ALL) before hematopoietic cell transplantation (HCT). Non-TBI regimens have incorporated busulfan (Bu) to decrease toxicity. This retrospective study analyzed TBI and Bu on outcomes of ALL patients 18–60 years old, in first or second complete remission (CR), undergoing HLA-compatible sibling, related, or unrelated donor HCT, who reported to the Center for International Blood and Marrow Transplant Research from 2005 to 2014. TBI plus etoposide (25%) or cyclophosphamide (75%) was used in 819 patients, and intravenous Bu plus fludarabine (41%), clofarabine (30%), cyclophosphamide (15%), or melphalan (13%) was used in 299 patients. Bu-containing regimens were analyzed together, since no significant differences for patient outcomes were noted between them. Bu patients were older, with better performance status; took longer to achieve first CR and receive HCT; were treated more recently; and were more likely to receive peripheral blood grafts, antithymocyte globulin, or tyrosine kinase inhibitors. With median follow-up of 3.6 years for Bu and 5.3 years for TBI, adjusted 3-year outcomes showed treatment-related mortality Bu 19% versus TBI 25% (P?=?.04); relapse Bu 37% versus TBI 28% (P?=?.007); disease-free survival (DFS) Bu 45% versus TBI 48% (P?=?.35); and overall survival (OS) Bu 57% versus TBI 53% (P?=?.35). In multivariate analysis, Bu patients had higher risk of relapse (relative risk, 1.46; 95% confidence interval, 1.15 to 1.85; P?=?.002) compared with TBI patients. Despite the higher relapse, Bu-containing conditioning led to similar OS and DFS following HCT for ALL.     

Total Body Irradiation Is Safe and Similarly Effective as Chemotherapy-Only Conditioning in Autologous Stem Cell Transplantation for Mantle Cell Lymphoma

Autologous stem cell transplant (ASCT) consolidation has become a standard approach for patients with mantle cell lymphoma (MCL), yet there is little consensus on the role of total body irradiation (TBI) as part of high-dose transplantation conditioning. We analyzed 75 consecutive patients with MCL who underwent ASCT at our institution between 2001 and 2011 with either TBI-based (n?=?43) or carmustine, etoposide, cytarabine, melphalan (BEAM; n?=?32) high-dose conditioning. Most patients (97%) had chemosensitive disease and underwent transplantation in first remission (89%). On univariate analysis, TBI conditioning was associated with a trend toward improved PFS (hazard ratio [HR], .53; 95% confidence interval [CI], .28-1.00; P?=?.052) and similar OS (HR, .59; 95% CI, .26-1.35; P?=?.21), with a median follow-up of 6.3 years in the TBI group and 6.6 years in the BEAM group. The 5-year PFS was 66% in the TBI group versus 52% in the BEAM group; OS was 82% versus 68%, respectively. However, on multivariate analysis, TBI-based conditioning was not significantly associated with PFS (HR, .57; 95% CI .24-1.34; P?=?.20), after controlling for age, disease status at ASCT, and receipt of post-transplantation rituximab maintenance. Likewise, early toxicity, nonrelapse mortality, and secondary malignancies were similar in the 2 groups. Our data suggest that both TBI and BEAM-based conditioning regimens remain viable conditioning options for patients with MCL undergoing ASCT.     

Clinical application of the OneDose Patient Dosimetry System for total body irradiation

The OneDose Patient Dosimetry System (Sicel Technologies) is a new dosimeter based on metal oxide semiconductor field-effect transistor technology and designed for the in vivo measurement of patient dose during radiotherapy. In vivo dosimetry for total body irradiation (TBI) is challenging due to the extended treatment distance, low dose rates and beam spoilers. Phantom results confirm the suitability of the dosimeter for TBI in terms of inherent build-up, post-irradiation fading, accuracy, reproducibility, linearity and temperature dependence. Directional dependence is significant and should be taken into account. The OneDose dosimeters were also trialed in vivo for two TBI patients and the dose measured compared to conventional dosimeter measurements using an ionization chamber and thermoluminescent dosimeters (TLD), with agreement to within 2.2% and 3.9%, respectively. Phantom and patient results confirm that the OneDose patient dosimetry system is a practical and convenient alternative to TLDs for TBI in vivo dosimetry. For increased confidence in results with this dosimeter, we recommend that two dosimeters be used for each site of interest.     

Comparison of D2O and ethanol dilutions in total body water measurements in humans

Total body water was measured by ethanol dilution and D₂O stable isotope dilution in a group of 20 healthy volunteers (5 females and 15 males), predominantly 23- to 31-year-old students. Both indicator substances were given orally with an ethanol burden of 0.8 g/kg body weight and a D₂O burden of 0.1 g/kg body weight after 12-h food and fluid restriction. This first direct comparison of total body water (TBW) from ethanol and D₂O dilutions revealed the ethanol compartments to be smaller than those of D₂O. The quotient of TBW (ethanol)/TBW (D₂O) was 97.7% , which is the order of the quotient TBW (H₂ ¹⁸O)/TBW (D₂O) (=97%), well known from the literature and taken to represent relatively exactly the value of TBW overestimation (based on H/D exchange for acid protons) following D₂O dilution [36]. Thus the value of TBW (ethanol) is almost identical to that of H₂ ¹⁸O, which provides direct evidence that ethanol is distributed only in the body water.Abbreviations TBW total body water - BIW water content in whole blood - GC gas chromatography