Reactions of isolated rat aorta to X-irradiation

The reaction of isolated helical strips of rat aorta to X-irradiation was studied: X-rays (50 kV) induced a reproducible, reversible contractile response at threshold doses of 2.5 Gy (60 Gy/min) and 10 Gy (30 Gy/min). After repeated irradiation with the same doses at equal time intervals and constant dose-rate (for example 50 Gy every 15 min, dose-rate 60 Gy/min) the contractile response was progressively diminished, i.e. a tachyphylaxis appeared. The preparations still reacted even after total doses over 1000 Gy. The X-ray induced contractile responses were dose- and dose-rate dependent. Quantitative analysis indicated no essential differences in the radiation-induced contractile response when recorded under isometric or isotonic conditions. After hypothermia (20 degrees C) or hyperthermia (42 degrees C) no visible radiation response could be induced. Part of the aortic strips were spontaneously active: X-ray doses of 5 to 10 Gy stimulated, while doses of 100 to 200 Gy inhibited or blocked the spontaneous phasic activity. A comparison between the immediate X-ray reaction of vascular and non-vascular smooth muscle preparations is given. Participation of cholinergic and adrenergic mechanisms in the X-ray induced contractions of rat aorta seems to be ruled out, because the blocking agents atropine, phentolamine, and bretylium had no effect.     

X射线诱导非小细胞肺癌A549细胞凋亡的适应性反应及相关miRNA筛选的研究

目的 研究X射线辐射诱导非小细胞肺癌（NSCLC）A549细胞凋亡的适应性反应,并筛选适应性反应相关的微RNA（miRNA）。 方法 将NSCLC A549细胞分为6组,包括 50 mGy+20 Gy、200 mGy+20 Gy、20 Gy、50 mGy、200 mGy照射组及对照组（0 Gy）,前2组细胞分别用50、200 mGy初始剂量进行照射,培养6 h后用20 Gy的效应剂量进行照射,20 Gy、50 mGy、200 mGy照射组同时进行照射。培养24 h后使用流式细胞仪检测细胞凋亡情况。利用小RNA测序技术筛选差异表达miRNA,并对其靶基因进行基因本体（GO）及京都基因与基因组百科全书（KEGG）通路的功能富集分析。采用实时荧光定量PCR（qRT-PCR）对部分差异表达miRNA进行验证。2组间数据的比较采用Welch t检验。 结果 50 mGy+20 Gy照射组和200 mGy+20 Gy照射组的A549细胞早期凋亡率分别为（1.81±0.11）%和（2.17±0.19）%,低于20 Gy照射组的（4.54±0.23）%,且差异均有统计学意义（t=10.680、8.006,均P<0.01）。与20 Gy照射组相比,50 mGy+20 Gy照射组和200 mGy+20 Gy照射组共同差异表达趋势miRNA有1个上调（miR-3662）、15个下调（miR-185-3p、miR-1908-5p、miR-1307-5p、miR-182-3p、miR-92a-3p、miR-582-5p、miR-501-3p、miR-138-5P、miR-1260b、miR-484、miR-378d、miR-193b-3P、miR-127-3p、miR-1303及miR-654-5p）。GO富集分析结果显示,差异表达miRNA调控靶基因功能显著富集于细胞通讯调节、代谢过程的正向调节、代谢信号的调节、酶结合及催化活性等过程。KEGG富集分析结果显示,靶基因相关信号通路显著富集于溶酶体、丝裂原活化蛋白激酶、Ras和内吞作用等信号通路。qRT-PCR检测结果显示,miRNA表达情况与基因芯片结果趋势一致（10个miRNA表达水平得到验证）。 结论 X射线50、200 mGy照射剂量均能诱导NSCLC A549细胞凋亡的适应性反应,并筛选到一组共同差异表达的miRNA,可能在X射线辐射诱导细胞凋亡的适应性反应中发挥了重要作用,有可能成为调节电离辐射生物效应的潜在靶点。     

The effect of age and the proportion of renal tissue irradiated on the apparent radiosensitivity of the pig kidney

In 14-week-old (immature) and 45-week-old (mature) pigs either the right kidney (unilateral irradiation, UI) or both kidneys (bilateral irradiation, BI) were irradiated. The kidneys of immature pigs received single doses of 7.0-12.6 Gy of 250 kV X-rays; mature pigs received single doses of 7.8-14.0 Gy of 60Co gamma-rays. These were assumed to be approximately equivalent to the X-ray doses using a RBE of 0.9 gamma-rays/X-rays. The glomerular filtration rates (GFR) and effective renal plasma flows (ERPF), were determined for up to 24 weeks after irradiation. From these data dose-effect curves were obtained by determining, at each dose level, the percentage of irradiated kidneys which exhibited a greater than or equal to 50 per cent reduction in GFR and ERPF. 60Co gamma-ray doses were normalised to approximately equivalent X-ray doses. The dose-effect curves were fitted by probit analysis, and ED50 values (+/- SE) calculated for both GFR and ERPF. Similar conclusions could be drawn from the results obtained following the determination of both GFR and ERPF. However, the ED50 values obtained for ERPF were significantly lower than those for GFR (p less than 0.05). In 14-week-old animals the kidney of UI animals was significantly more radiosensitive than that of BI animals, i.e. the ED50 values, in terms of GFR, were 8.74 +/- 0.31 Gy and 10.97 +/- 0.23 Gy, respectively (p less than 0.001). In 45-week-old pigs the reverse was true; the ED50 values were 12.67 +/- 0.34 Gy and 8.78 +/- 0.15 Gy (p less than 0.001) for unilateral- or bilateral-irradiated animals, respectively. The kidney of BI mature animals appeared to be as radiosensitive as the UI immature pigs. Thus the renal response to radiation was markedly influenced by the age of the animals and by the proportion of the renal tissue irradiated.     

The dose response of normoxic polymer gel dosimeters measured using X-ray CT

X-ray CT was used to determine the dose response of normoxic polymer gel dosimeters. Normoxic polymer gel dosimeters were manufactured and irradiated up to 150 Gy. Up to 50 CT images were acquired on a Toshiba Aquilion Multislice CT scanner using protocols for 80 kV and 135 kV to determine dose response. HU-dose sensitivity, the linear regression of data for the HU versus dose for the linear part of the curve up to 60 Gy was 0.38+/-0.07 HU Gy(-1) for 135 kV and 0.37+/-0.01 HU Gy(-1) for 80 kV. Dose resolution was found to be < 1.3 Gy for an absorbed dose range up to 70 Gy for 135 kV, similar to that measured previously for polyacrylamide gel (PAG). Although the HU-dose sensitivity was lower than that previously measured for PAG gel dosimeters it had a greater range of absorbed dose indicating that normoxic polymer gel dosimeters have potential in CT gel dosimetry.     

淫羊藿甙对辐照小鼠的抗凋亡作用与半胱天冬酶活性的相关性研究

目的：观察淫羊藿甙抗辐射损伤作用，并探讨其抗辐射损伤机制。方法：KM种小鼠于60Coγ射线照射前48，24h及照后即刻灌胃淫羊藿甙，剂量分别为1，10，100mg/kg，照射剂量8．0Gy，观察受照射小鼠30d存活率和死亡动物平均存活时间。另外观察淫羊藿甙对l锄种小鼠受5．5Gy 60Coγ射线照射后小鼠胸腺、脾脏和骨髓细胞凋亡率、半胱天冬酶-3(caspase-3)和半胱天冬酶-8(caspase-8))活性的影响。结果：中剂量淫羊藿甙组30d存活率较照射对照组提高50％，死亡动物平均存活时间延长2．5d。照射对照组胸腺、脾脏和骨髓细胞在照射后6，12和24h均有凋亡。胸腺和脾脏于照射后12h凋亡率最高，骨髓于照后6h凋亡率最高。照射24h后，3种组织的凋亡串均明显降低。中剂量淫羊藿甙可降低照射后6，12h胸腺、脾脏、骨髓细胞凋亡率和照射后24h脾脏、骨髓细胞凋亡率，抑制照射后6hcaspase-3活性，对半胱天冬酶-8活性无影响。结论：淫羊藿甙具有抗辐射损伤作用，其机制之一可能是通过抑制caspase-3活性降低细胞凋亡率。     

低剂量辐射诱导小鼠胸腺细胞及其亚组的适应性反应

目的研究低剂量辐射预先照射以及随后大剂量照射后小鼠胸腺细胞Ｔ细胞受体（ＴＣＲ）、ＣＤ３、ＣＤ４和ＣＤ８分子表达的变化。方法ＴＣＲ、ＣＤ３表达采用间接荧光流式细胞术检测,ＣＤ４、ＣＤ８表达采用双参数直接免疫荧光流式细胞术检测。结果实验结果表明：单纯１５ＧｙＸ射线全身照射后ＴＣＲ,ＣＤ３阳性细胞数以及ＣＤ４－Ｄ８－,ＣＤ４＋ＣＤ８＋,ＣＤ４＋ＣＤ８－和ＣＤ４－ＣＤ８＋细胞数明显减少,当１５ＧｙＸ射线全身照射前６小时预先照射００７５Ｇｙ时,可明显减轻其后１５Ｇｙ照射对ＴＣＲ＋,ＣＤ３＋,ＣＤ４＋ＣＤ８＋,ＣＤ４＋ＣＤ８－和ＣＤ４－ＣＤ８＋的损伤作用。表现为各亚组细胞数显著高于单纯１５Ｇｙ照射组。ＣＤ４－ＣＤ８－亚组的细胞数无明显变化。结论００７５ＧｙＸ射线全身照射能够诱导胸腺细胞ＴＣＲ＋,ＣＤ３＋,ＣＤ４＋ＣＤ８＋,ＣＤ４＋ＣＤ８－和ＣＤ４－ＣＤ８＋亚组细胞的适应性反应。     

Effect of radiation on tumor-specific delayed-type hypersensitivity (DTH) response in mice

Delayed-type hypersensitivity (DTH) response is generally considered as one of major mechanism of anti-tumor immunity in vivo. We studied the effect of radiation on the immune spleen cells mediating tumor-specific DTH response based on an local adoptive transfer system. The spleen cells from C3H mice which were immunized with syngenic MH134 hepatoma cells were employed for the effector cells. The immune spleen cells were irradiated in vitro. Then the spleen cells and mitomycin C (MMC)-treated MH134 cells were mixed and inoculated into the hind footpad of normal C3H mice. Twenty-four hours later, the thickness of the footpad was measured with micrometer and increase in the footpad thickness was calculated comparing with a value before the inoculation. Irradiation with 4 Gy-12 Gy did not affect the DTH response. Then irradiation over 16 Gy dose dependently decreased the DTH response. Irradiation with 20 Gy decreased the DTH response about 50% and 28 Gy abolished the response to a control level. As two types of cells, antigen specific effector T cells and non-specific effector cells such as macrophages, are required to induce DTH response, we studied which type of cells is suppressed by irradiation. Non-irradiated normal spleen cells as a source of non-specific effector cells were added into the irradiated immune spleen cells. The addition of normal spleen cells to 20 Gy irradiated immune spleen cells recovered the DTH response to a control level of non-irradiated group. The other hand, the addition of normal spleen cells to 32 Gy irradiated immune spleen cells failed to recover the DTH response.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immediate mechanical reactions of isolated human detrusor muscle on x-irradiation.

The mechanical activity (isotonic registration) of isolated detrusor (smooth) muscle preparations from the human urinary bladder (surgical material) is investigated. The preparations reacted on X-irradiation (50 kV) with an immediate dose-dependent tonic contraction at threshold-doses of 100 to 1000 R (1 to 3 kR/min). The contraction was either reversible, semireversible or persistent, and the basal muscle tone was elevated. A tachyphylactic reaction was observed. The phasic activity of the preparations was temporarily increased, then inhibited after irradiation. The radiation-induced changes of the human and guinea-pig detrusor muscle are compared and their possible relation to the functional disturbances of the urinary bladder after radiotherapy is discussed.     

Soft X-Ray Therapy of Recurrent Pterygium – an Alternative to 90Sr Eye Applicators

BACKGROUND: Analysis of effectiveness of perioperative 20 kV soft X-ray irradiation in recurrent pterygium as an alternative to postoperative 90Sr beta irradiation. PATIENTS AND METHODS: Between 1987 and 2000 a total of 65 patients with 81 pterygia were treated with 20 kV X-ray therapy in the course of surgical treatment of recurrent pterygium. Until 1995 simple excision (bare sclera technique) followed by postoperative irradiation (generally four fractions of 5 Gy) was applied, with radiation starting on mean 4 days following surgery (34 cases, mean follow-up 52 months). Since 1995 we have changed our policy to a perioperative regimen starting with a single dose of 7 Gy prior to microsurgical excision with conjunctival autograft and proceeding within 24 hours with 5 Gy single dose to the surgical bed and then every other day to a total dose of 27 Gy (47 cases, mean follow-up 31 months). Recurrence rate was calculated by Kaplan Meier method. A multivariate Cox regression analysis of prognostic factors for recurrence was performed. RESULTS: A total of 19 recurrences were observed, 15 in the historical postoperative group and four in the perioperative group. Actuarial 2- and 5-year recurrence rate is 9% in the "new treatment group" compared to 34% and 56% in the historical group (p = 0.001). Only one of the four recurrences among the pre- and postoperatively irradiated group required a new surgical procedure. In this case radiation had been terminated at 17 Gy. Actuarial rate of surgical reintervention was only 2% at 2 and 5 years compared to 28% and 36% in the historical group. In multivariate Cox regression analysis only the new treatment strategy was found to influence control rate significantly. Until now no case of severe side effects like scleral necrosis or thinning, symble-pharon, radiation-induced cataract or glaucoma were observed in both groups. CONCLUSION: The combination of pre- and postoperative 20 kV X-ray therapy and microsurgical excision combined with conjunctival autograft is a highly effective treatment to prevent recurrence in the high-risk group of recurrent pterygia and can be recommended as an alternative to postoperative 90Sr beta irradiation.     

Enhancement by hyperthermia of the 'early delayed' and 'late delayed' radiation response of the rat cervical spinal cord.

The cervical spinal cord (C5-T5) of female Wistar WU rats was irradiated with 250 kV X-rays (15-32 Gy). Heat was applied at approximately the same site 7 +/- 1 min after X-rays. 'Early delayed' paralysis of the forelegs was observed 5-10 months after treatment. The ED50 (+/- SE) after single-dose irradiation alone was 25.8 +/- 0.4 Gy. 'Late delayed' paralysis and paresis were observed 11-21 months after irradiation with an ED50 (X-rays alone) of 22.7 +/- 0.6 Gy. The data for late paralysis, late paresis and minor neurological symptoms were pooled resulting in an ED50 (+/- SE) of 20.6 +/- 0.7 Gy. Hyperthermia enhanced the radiation response. Thermal enhancement ratios (TER) in the 'early delayed' response after a 30 min treatment with 41.1 +/- 0.4 degrees C 42.1 +/- 0.4 degrees C and 42.9 +/- 0.4 degrees C were 1.07 +/- 0.08, 1.17 +/- 0.08 and 1.12 +/- 0.04, respectively. For the 'late delayed' radiation response concerning paralysis and paresis the TER after 30 min at 41.1 degrees C and 42.1 degrees C were 1.25 +/- 0.10 and 1.31 +/- 0.07, respectively. The latent period for paralysis was not significantly affected. Pathological examination of the spinal cord after combined treatment of X-rays and hyperthermia showed focal demyelination with white matter necrosis and vascular injury in animals as an indication of 'early delayed' and 'late delayed' paralysis, respectively. This was not different from histopathological changes observed after irradiation alone.     

缝隙连接蛋白43在受照人血管内皮细胞中的改变及其对受照细胞刚性的作用

目的:研究X射线对人脐静脉内皮细胞(HUVEC)中缝隙连接蛋白43(Cx43)的表达、分布和细胞刚性的影响,初步探讨Cx43对受照细胞刚性的调控作用。方法:采用Western blot方法检测10 Gy X射线照射后不同时间(0、6、12、24和48 h)和不同剂量X射线(0、2.5、5、10和20 Gy)照射后12 ...     

Late radiation fibrosis in rat lung following protons and 250 kV X-rays irradiation

To investigate the biological effectiveness of proton beams in the development of pulmonary fibrosis the lungs of male 7-week-old Wistar rats were locally irradiated with a single dose of 10-50 Gy of 250 kV X-rays and modulated, 250 MeV protons at Particle Radiation Medical Science Center (PARMS). Animals were sacrificed serially after 3, 6, 9 and 12 months at which times the development of the fibrotic lesion in alveolar walls and peribronchial connective tissues was assessed quantitatively by analysis of microscopic images of Azan-Mallory stained sections. Fibrosis index (FI) values in alveolar walls and peribronchial tissues were defined as the fraction (in percent) of a specific image area, the gray level of which represents collagen deposits. Using this FI values, the increase of fibrotic lesion following 0-40 Gy of X-rays irradiation as a function of time were observed better in alveolar walls than in peribronchial tissues. Compared with 250 kV X-rays, 30 Gy of proton beams irradiation produced less increase in the time course of FI values of alveolar walls and dose-response curve at 12 months later suggested that the fibrotic lesion in alveolar walls after protons exposure of the doses above 30 Gy might develop more slowly.     

Effect of EGFR-inhibition on the radiation response of oral mucosa: experimental studies in mouse tongue epithelium

The aim was to quantify the effect of selective inhibition of the epidermal growth factor receptor (EGFR) on the radiation response of mouse oral mucosa to daily fractionated irradiation. Irradiation comprised graded single doses of 25 kV X-rays to the lower tongue surface or fractionated doses of 5 x 3 Gy week(-1) (200 kV X-rays) over 1 or 2 weeks, followed by graded local doses, to generate full dose-effect curves. For selective inhibition of EGFR, BIBX1382BS, a tyrosine kinase inhibitor, was administered orally at a dose of 50 mg kg(-1), for the entire overall treatment time. The ED50 (the dose expected to induce ulcer in 50% of the mice) for untreated mucosa was 11.9 +/- 1.2 Gy. Fractionated irradiation administered over 1 or 2 weeks yielded ED50 values for the concluding test irradiation of 6.7 +/- 2.1 and 6.5 +/- 1.9 Gy, respectively. Administration of BIBX1382BS resulted in a non-significant increase of the top-up ED50 to 8.3 +/- 1.6 Gy (p = 0.1197) after 1 week and to 7.6 +/- 1.6 Gy (p = 0.2263) after 2 weeks. EGFR inhibition does not alter the radiation response of oral mucosa to fractionated irradiation or interfere with mucosal repopulation processes. This indicates that the regulation of mucosal repopulation is largely independent of EGFR activation.     

Contractile reaction of isolated frog aorta after X-irradiation

The action of X-rays (50 kV, filtered by 0.3 mm Al) on helical strip of frog aorta (rana esculenta) has been investigated. The isolated preparations have a stable basal tone and are radio-sensitive to X-rays which induce reversible, dose-dependent, contractile responses. After repeated irradiation tachyphylaxis appears. The threshold doses are about 250 Rat 3 to 6 kR/min, antiadrenergic (phentolamine, propranolol), anticholinergic (atropin), antihistaminic (Neo-Bridal) and serotoninergic (Deseril) drugs have no visible influence on the X-ray induced reaction, i.e. these action mechanisms of the irradiation-induced contraction do not seem probable. Theophylline and cAMP inhibit the X-ray contraction probably non-specifically. Indometacin also inhibits the X-ray contraction: this suggests participation of prostaglandin-mechanism on the contraction of frog aorta after irradiation.     

Radiotherapy in endocrine ophthalmopathy--evaluation of 56 cases

The authors present the radiotherapeutic results achieved in 56 patients with endocrine ophthalmopathy, 15 out of them with severe, so-called malignant course. All patients were irradiated conventionally with small doses between 3 and 10 Gy at the surface. For this purpose, a deep therapy unit with 250 kV was used. The X-ray irradiation produced an improvement in 62% of the cases; the separate evaluation of cases with malignant course showed an improvement in nine cases. Thus the results produced by this method are as good as those of high doses, the greater possibilities in case of recurrence, however, are to be considered as an advantage. The irradiation should be applied early, and the simultaneous administration of a cortisone preparation is preferred by our team.     

Effects of dexpanthenol with or without Aloe vera extract on radiation-induced oral mucositis: preclinical studies

PURPOSE: To define the effect of dexpanthenol with or without Aloe vera extract on radiation-induced oral mucositis. MATERIALS AND METHODS: Mouse tongue mucosal ulceration was analysed as the clinically relevant endpoint. Graded single or fractionated dose irradiation (10 x 3 Gy/2 weeks, graded test doses on day 14) were combined with topical administration of dexpanthenol or a base, with or without Aloe vera extract. The formulations were applied for 14 days (single dose) or 24 days after the first fraction. RESULTS: Single dose irradiation resulted in an ED50 (dose at which a positive mucosal response was expected in 50% of the animals irradiated) of 11.9+/-1.2 Gy. None of the formulations yielded a significant change in incidence or time course of ulceration. Test irradiation after 10 x 3 Gy gave an ED50 of 9.0+/-0.1 Gy. Base treatment increased the ED50-values to 10.5+/-0.8 Gy (p = 0.0095) and 9.9+/-0.7 Gy (p = 0.0445) without or with Aloe vera. Dexpanthenol resulted in ED50 values of 9.5+/-0.1 Gy without Aloe vera (p > 0.05), and of 10.9+/-0.9 Gy (p = 0.0035) with Aloe vera. The latent time to ulceration was prolonged, compared to the control (6.3 days) without Aloe vera (8.0-8.2 days, p < 0.001) and with dexpanthenol and Aloe vera (7.3 days, p = 0.0239). CONCLUSIONS: With single dose irradiation, neither dexpanthenol nor Aloe vera extract significantly changed the oral mucosal radiation response. With fractionated irradiation, drug administration significantly increased the isoeffective radiation doses, independent of dexpanthenol or Aloe vera content. Neither dexpanthenol nor Aloe vera display a prophylactic potential.     

Volume and dose–response effects for severe symptomatic pneumonitis after fractionated irradiation of canine lung

Purpose : To study the dose-related incidence of severe symptomatic pneumonitis following fractionated irradiation applied to three different volumes of lung in normal beagle dogs. Materials and methods : A three-dimensional treatment planning system was used to design mediastinal fields of increasing width to irradiate 33%, 67% or 100% of both lungs combined in 128 normal beagle dogs. Total doses, ranging from 27 to 72 Gy, were delivered in 1.5Gy fractions over 6 weeks. Results : No dogs irradiated to 33% of their total lung volume developed severe symptomatic pneumonitis. In the 67% volume group, logistic fit of the data showed a dose–response curve with a 50% probability of developing severe symptomatic pneumonitis (ED50) after a total dose of 56.0 Gy (52.2–66.0 Gy, 95% confidence interval, CI). The more clinically relevant ED 5 for the first 6 months after irradiation of 67% of the lung was 48.1 Gy (18.5–52.0 Gy, 95% CI). The ED 50 and ED 5 values after irradiation of the whole lung (100%) were 44.1 Gy (41.2–53.5 Gy, 95% CI) and 39.1 Gy (8.8–41.8 Gy, 95% CI) respectively. Conclusion : Severe symptomatic pneumonitis proved to be a very informative volume-effect endpoint, clearly demonstrating that irradiated lung volume is a critical parameter to be considered in assigning thoracic radiotherapy treatment parameters. Volume effects in lung are dependent on the compensatory capacity of the nonirradiated lung. Underlying pathophysiology of irradiated tissue, as well as decreased compensatory capacity of nonirradiated tissue may have a strong effect on the dose-volume response.     

Ionizing non-fatal whole-body irradiation inhibits Ca2+-dependent K+ channels in endothelial cells of rat coronary artery: possible contribution to depression of endothelium-dependent vascular relaxation

PURPOSE: The goal of this study was to evaluate the influence of ionizing irradiation on large conductance Ca2+-dependent potassium (BKCa) channels in rat coronary endothelial cells. MATERIALS AND METHODS: Rats were exposed to a 6 Gy dose from a cobalt60 source. Experimental design of this study comprised recording of contractile force using isolated rat aortic rings and whole-cell patch clamp techniques to study whole-cell potassium currents in isolated rat coronary artery endothelial cells. RESULTS: It has been shown that outward potassium currents in endothelial cells 9 days after irradiation appear to be suppressed or even totally abolished. The reversal potential for these currents in irradiated cells was shifted to more positive values. Paxilline (500 nM), an inhibitor of BKCa channels, had no or only a negligible effect on irradiated cells. The experiments using isolated aortic rings demonstrated that both paxilline and irradiation significantly shifted the acetylcholine dependent concentration-relaxation response curve to the right. Irradiated tissues were insensitive to paxilline. CONCLUSION: The results suggest that non-fatal, whole-body gamma-irradiation suppresses large conductance, calcium-activated potassium channels, which control the driving force for Ca2+ entry and therefore Ca2+ dependent nitric oxide (NO) synthesis in endothelial cells. This may contribute, in part, to radiation-induced endothelium dysfunction and an increase in arterial blood pressure.     

脑血管造影术中X射线机房内辐射剂量分布研究

目的 研究脑血管造影术中不同照射方向下X射线机房内辐射剂量场的分布情况.方法 选用脑血管造影术程序,选取后前位、前后位、右前斜30°、左前斜30°、右侧位和左侧位6种照射方式,使用451B型空气电离室巡测仪对以散射模体为中心、半径为3 m范围内的辐射场的剂量率分布进行测量.结果 后前位及右侧位照射时主要操作人员所受到的辐射剂量最低,均为0.4 mGy/h;左侧位照射时主要操作人员受到的辐射剂量最高,为1.54 mGy/h;机架侧区域的辐射剂量水平最低,均小于10 μGy/h.结论 在脑血管造影术中,医护操作人员应尽可能选择剂量较低的后前位及右侧位照射方式投照,并合理选择工作位置,可明显降低受照剂量.

Abstract：

Objective To determine the distribution of irradiation dose in X-ray room with different radiation directions in cerebral angiography operations.Methods The Model 451B air ionization chamber survey meter was used to measure the irradiation dose distribution in the X-ray room when cerebral angiographies were performed at high kV and high dose.The doses were measured within 3 m when the phantom was irradiated in posterior-anterior (PA) position, anterior-posterior(AP) position, right anterior oblique (RAO) 30°, left anterior oblique (LAO) 30°, right-lateral (RL) position, and left-lateral(LL) position, respectively.Results Both the relative data and the distribution curves of the six radiation directions were obtained by using the same interventional operation model.The irradiation dose to the primary operator was minimal in P-A and RL positions,at 0.4 mGy/h, and was maximal in LL position, at up to 1.54 mGy/h.Furthermore, the lowest irradiation dose level was found to be lower than 10 μ Gy/h at the side of the framework field.Conclusions Low-irradiation position and rational work place were proposed to reduce the operators' absorption dose during interventional radiology procedures.