辐射防护内照射剂量估算软件的开发

目的 建立辐射防护内照射剂量估算的计算机系统。方法 基于医学内照射吸收剂量(MIRD)的人体及其器官的数学模型,采用MS Visual Basic 6.0编程语言,结合内照射剂量学方法,建立辐射防护内照射剂量估算的计算机系统。结果 成功研制了能够用于内照射剂量估算的计算机系统。结论 本系统方便、快捷,能够用于辐射防护多种情况中的内照射剂量估算,而且也能用于核突发事件内照射的剂量估算。     

Fast neutron irradiation of metastatic cervical adenopathy: the results of a randomized RTOG study

Between 1977 and 1982, 199 evaluable patients with measurable cervical adenopathy were entered on a prospective, randomized RTOG study evaluating the use of fast neutrons in treatment of advanced, inoperable squamous cell carcinomas of the head and neck region. One hundred-eleven patients were randomized to receive mixed beam radiation therapy, and 88 were randomized to the photon control treatment. The complete response rates were 86% for mixed beam vs 75% for photons for Stage N1 nodes, 62% for mixed beam vs 48% for photons for Stage N2 nodes, and 63% for mixed beam vs 53% for photons for N3 nodes. The percents of patients remaining free of their adenopathy for two years were 78% for mixed beam vs 55% for photons for Stage N1 nodes, 39% for both mixed beam and photons for N2 nodes and 24% for mixed beam vs 13% for photons for N3 nodes. The median disease-free status was 20.3 months for mixed beam treated patients and 6.4 months for photon-treated patients. Patients who had clearance of cervical adenopathy survived significantly longer than those who did not.     

Endocrine profiles of patients with testicular tumors treated with radiotherapy

Blood samples for hormone analysis were obtained 5 to 20 years post-therapy from 12 men with testicular tumors who were originally treated by unilateral orchiectomy followed by abdominal and/or pelvic irradiation. In nine patients (75%) the levels of FSH and LH, and in one patient (8%) the testosterone values, were outside the ranges found in age- and sex-matched controls. From this retrospective study we conclude that, even when the remaining testis is kept outside the field of radiation, significant radiation damage occurs, mainly through scatter. This damage is more likely to occur if the hemiscrotum is irradiated. Methods of shielding are available to reduce the dose received by the contralateral testis.     

Response of mouse lung to irradiation at different dose-rates

Groups of LAF1 mice were given thoracic irradiation using 60Co gamma-rays at dose-rates of 0.05 Gy/min (LDR) or 1.1 Gy/min (HDR) and the death of the animals was monitored as a function of time. It was found that the time pattern of animal deaths was similar for the two different dose-rates. Dose response curves for animals dying at various times up to 500 days after irradiation were calculated and the LD50 values determined. The curves for the LD50 values, plotted as a function of the time at analysis for treatment at HDR or LDR, were essentially parallel to each other but separated by a factor (LDR/HDR) of about 1.8. This indicates that the sparing effect of LDR treatment is the same for deaths occurring during the early pneumonitis phase or during the late fibrotic phase of lung damage. The available information on the response of patients to whole thoracic irradiation, given for either palliation or prior to bone marrow transplantation, suggests that for similar dose-rates to those studied here the ratio (LDR/HDR) is only 1.2-1.3. This difference between the animal and human data may reflect the modifying effect of the large doses of cytotoxic drugs used in combination with the irradiation of bone marrow transplant patients.     

Late effects of 50 McVd→Be neutron and cobalt-60 irradiation of rhesus monkey cervical spinal cord

The cervical spinal cords of 30 rhesus monkeys were irradiated with 50 MeV_d→Be neutrons or ⁶⁰Co gamma rays to evaluate the dose-response relationships for radiation myelopathy. Three groups were treated with 50 MeV_d→Be neutrons using dosage schedules of 1300 rad_mγ (Group I), 1425 rad_mγ (Group II), or 1550 rad_mγ (Group III) in nine fractions over 29 days. Three groups were irradiated with ⁶⁰Co gamma rays using dosage schedules of 4620 rad_mγ (Group IV), 5390 rad_mγ (Group V), or 5940 rad_mγ (Group VI) in 22 fractions over 29 days. A significant dose-response relationship was observed for the groups treated with neutrons. Whereas none of the monkeys in Group I showed clinical evidence of neurologic dysfunction, all five animals in Group III became paralyzed. One animal in Group II developed transient neck stiffness and mild unilateral leg paresis. No definitive signs of neurologic injury were seen in any of the animals irradiated with ⁶⁰Co. The histopathologic changes correlated well with the clinical observations. All of the animals in Group III exhibited moderate to severe malacia and demyelination of the white matter of the cervical spinal cord. The histologic data indicated that the RBE for five times weekly fractionation (～270 rad_mγ⁶⁰Co. fractions) was in the range of 4.2 to 4.6, since the malacia and demyelination in the spinal cords irradiated with 5940 rad_mγ of ⁶⁰Co. γ-rays were greater than that observed in the spinal cords irradiated with 1300 rad_mγ of neutrons but less than the changes in those irradiated with 1425 rad_mγ of neutrons.     

Presumptive downstaging from preoperative irradiation for bladder cancer as determined by flow cytometry: Preliminary report

Presumptive tumor downstaging was evaluated in 28 patients with grade 11 or III, solid, muscle-infiltrating bladder cancer (clinical category T3) treated by integrated irradiation (2000 rad to the whole pelvis in 5 days) and cystectomy (1–14 days later) by comparing the results of flow cytometry (FCM) on barbotage specimens obtained before and after irradiation (at the time of cystectomy) and the results of pretreatment clinical stage (T category) and post cystectomy pathological stage (P category). The patients were divided into three groups: (1) P > T, (2) P = T, and (3) P < T. All of the patients in this study had positive FCM specimens with an aneuploid stemline in the pre-irradiation specimen. A complete radiation response (CRR) was defined by FCM as disappearence of the aneuploid stem cell line. Of the 5 patients in the P < T group, 4 showed a CRR; of 20 patients in the P = T group, 8 showed a CRR; of the 3 patients in the P > T group, none showed a CRR. The proportion of patients in the various T/P groups is consistent with that previously observed in patients receiving integrated irradiation (2000 rad in 5 days) and cystectomy (1–14 days later). The overall downstaging response of 43 %, as determined by FCM, correlates well with the pathological downstaging rates of 40%–68% reported by others following high dose (4000–5000 rad) integrated irradiation cystectomy regimens; however, it is more than the 27 % rate reported with the low dose short course (2000 rad in 5 days) regimen. The correlation of the FCM findings with clinico-pathological downstaging is consistent with the possibility that FCM may be useful in identifying a favorable radiation response.     

Surfactant release as an early measure of radiation pneumonitis

The immediate release of surfactant into lung alveoli following irradiation has been studied as a potential indicator for the later development of radiation pneumonitis. Utilizing single dose radiation exposure to the whole thorax in male LAF₁/J mice, steep dose response curves for lavaged alveolar surfactant were identified at 7 and 28 days after exposure. Seven days after irradiation there was no elevation with doses up to and including 12 Gy; above this dose a detectable increase occurred. At 28 days the surfactant recovered by lavage was elevated compared to the levels seen at day 7 for all doses; doses > 12 Gy produced surfactant values significantly greater than those found in mice treated with 12 Gy or less. The radiation pulmonary lethality dose response curve assessed four months later indicated an LD₅₀ value of ～13 Gy. The early biochemical effect and the later radiation pneumonitis lethalities therefore closely coincided. The evidence strongly indicates that alveolar surfactant release uncovered hours to days after radiation exposure may be an early biochemical marker that predicts for subsequent pneumonitis radiation injury.     

Dosimetry of single fraction high dose total body irradiation as measured by thermoluminescent dosimeters

Eighty-five patients with acute myelogenous or acute lymphoblastic leukemia were treated at the City of Hope National Medicine Center with chemotherapy, total body irradiation, and bone marrow transplant. The average mid-line dose to these patients was 1002 rad with a uniformity of 8%.     

冠状动脉CT成像钙化积分扫描噪声与增强扫描噪声的相关性分析

目的：分析冠状动脉CT血管成像（CCTA）中对比增强前后图像噪声值的关系,探讨一种预测CTCA图像噪声的方法,从而为实施个体化剂量管理提供依据。方法：回顾性分析固定各扫描序列曝光参数的82例64层螺旋CT回顾性门控冠状动脉CTA的图像资料,研究钙化积分扫描（CACS）图像噪声（SD1）与对比增强扫描图像噪声（SD2）之间的线性相关性,以及体重指数（BMI）与对比增强扫描图像噪声（SD2）之间的线性相关性,并拟合出直线方程。结果：SD1与SD2之间直线相关系数r=0.94（P〈0.0001）,线性方程为SD2=1.29624×SD1＋1.20457;BMI与SD2之间的直线相关系数r=0.80（P〈0.0001）,线性方程为SD2=1.56067×BMI-10.76970。结论：在CTA各序列的曝光参数不变的情况下,对比增强前后图像噪声值之间存在高度线性相关性。钙化积分扫描噪声比体重指数能更精确地预测增强扫描图像的噪声,从而使基于钙化积分扫描噪声的个体化剂量控制成为可能。     

“Buchler”后装机在临床应用的评估(附宫颈癌135例五年疗效分析)

本文从临床角度对Buchler机的放射源和剂量学上进行初步评估,认为尚有不足之处,另总结1983年10月至1985年3月应用高剂量率Buchler机合并~(60)钴或9 Mev直线加速器对分期为Ⅱ、Ⅲ期的宫颈癌135例进行根治性放射治疗,其五年生存率分别是85.25％(52/61)和68.92％(51/74)全组五年生存率为76.03％(103/135)。