Microstructural Investigation of PM-355 Nuclear Track Detector Subjected to Low-Dose Gamma Irradiation: A Positron Annihilation Lifetime Study

Samples of the PM-355 polymeric solid state nuclear track detector were exposed to low gamma absorbed doses from 1 kGy (0.1 Mrad) up to 9 kGy (0.9 Mrad). Positron annihilation lifetime (PAL) in conjunction with transmission electron microscopy (TEM) and Thermo-gravimetric analysis (TGA) were performed on irradiated and pristine samples at room temperature. The observed lifetime spectra were resolved into three components where the ortho-positronium (o-Ps) lifetime component was associated with the pick-off annihilation of positronium trapped by the free volume. PAL studies of irradiated PM-355 samples showed that ortho-positronium (o-Ps) lifetime increases with an increase in dose up to 4 kGy and decreases at higher doses. In contrast, the intensity of the o-Ps component, I3, decreases with the dose up to about 2 kGy, followed by a much smooth decrease up to 7 kGy, and then it levels off. TGA analysis indicated that the PM-355 detector decomposed in one main breakdown stage. These results are discussed on the basis of chemical and physical changes occurring at the microscopic level in the PM-355 due to irradiation. Crosslinking dominates for doses between 1 and 4 kGy, while the degradation mechanism (Chain scission) prevails for doses up to 9 kGy.

Analytical and statistical calculation of gamma dose rate for the accident of losing the shield for Tehran Research Reactor

In this paper we study the analytical and statistical results of estimating the gamma dose rate at pool access floor in TRR when the core shield accidentally decreases to some non-permitted levels. Due to the risk of experimental techniques, we use the analytical and statistical methods. In normal conditions （no risk）, the discrepancies between experiment and two methods are justified and it is found that for such problems we have to normalize these methods to experimental results as follows： the analytical method by factor 0.13 and MCNP by 1.7.

Dose inter-comparison studies for ^(60)Co gamma-ray and electron beam irradiation in the year 2002

Dose inter-comparison studies for Co γ-ray and 10 MeV electron beam irradiation were carried out 60 from July to October in 2002. The purpose of the studies was to check the reliability of the alanine-PE film dosime- ters made by CIAE, which will be used as transfer standard dosimetry system mainly for electron beam irradiation. The expanded uncertainty of CIAE alanine/EPR dosimetry system was 4.1% for doses not higher than 10 kGy and 5.4% for those above 10 kGy (k=2). CIAE alanine-PE film dosimeters were sent to JAERI, RISO (National Labora- tory in Denmark) and INCT respectively, which were irradiated by Co gamma-rays or electron beams in each labo- 60 ratory. The irradiated dosimeters were then sent back to CIAE for electron paramagnetic resonance (EPR) analysis. The agreements were obtained to be ±1.9% for gamma-ray dose measurement and ±4.3% for electron beam dose measurement, which were all within the combined uncertainty of the reference and CIAE alanine/EPR dosimetry system. Furthermore, the overall mean ratio was found to be 0.995 with 1.8% in the coefficient of variation (CV). The preliminary inter-comparison studies indicated that CIAE film alanine/EPR dosimetry system had the potential to be used as a transfer dosimetry system for high dose measurement.

Dose Rate Calculation in the Vicinity of the Tunisian Gamma Irradiation

Dose rates calculations, in PMMA dosimeters, placed in the vicinity of the Tunisian 60Co gamma ray irradiator, have been achieved using a pencil like model. The obtained results are in good agreement with recent experimental data. Moreover, in this work we determine also the conversion factor between the dose rate deposited in a PMMA dosimeter and the one deposited in a reel medium. This factor is used to determine the dose deposited in a real irradiated medium such as foodstuff products.

Comparison of Gamma Pass Rate between the Dose-to-Water and Dose-to-Medium Reporting Modes for Patient-Specific QA Using a Helical Diode Array Dosimeter with a Fixed Phantom Density

Introduction: To compare the measured dose distributions to calculated ones in dose-to-water (Dw) and dose-to-medium (Dm) reporting modes for simple plans and patient-specific intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans using ArcCHECK with a fixed phantom density. Methods: The recommended density value of 1.18 g/cm3 for Acuros XB and X-ray voxel Monte Carlo was assigned to ArcCHECK on CT images. A total of 45 simple plans, including a 1-field plan, a 3-field plan, a 4-field plan, a half-arc plan from 270° to 90°, and a full-arc plan, were assessed. Subsequently, the patient-specific 96 IMRT and VMAT plans were evaluated. Gamma analysis with a 3% normalized global dose error and a 3 mm distance-to-agreement criteria (γ3%G/3mm) was performed in the Dw and Dm. The change in γ3%G/3mm between Dw and Dm were statistically analyzed using JMPPro11 software. Results: The median values of γ3%G/3mm for all simple plans for Dw and Dm were 98.1% (range, 75.2% - 100%) and 95.5% (range, 23.7% - 100%), respectively (p 0.01). In the patient-specific IMRT and VMAT plans, the median values of γ3%G/3mm for Dw and Dm were 98.6% (range, 90.1% - 100%) and 90.5% (range, 38.5% - 97.2%), respectively (p 0.01). Conclusion: Our results showed that the calculated and measured dose distributions were in good agreement for Dw, but were not for Dm. From the viewpoint of the rationale of dosimetry, Dw shows better agreement with measured dose distribution when using the fixedphantom density recommended by the vendor.

Assessment of Equivalent Radium Activity and Annual Effective Dose Due to Building Materials in Côte D’Ivoire by Gamma Spectrometry: Cases of Cement

Radioactivity is a natural phenomenon present in the universe. So, because of human life solidarity with a habitat, we are permanently in contact, especially through building materials. The objective of this work is the determination of the used cement radioactivity level in the buildings in Cote d'Ivoire. Thus, samples of grey and white cement currently used on Ivorian territory were taken. In order to determine the radioactivity level of this cement, samples were analyzed by using gamma spectrometry chain which contains a NaI (Tl) scintillation detector designed by the German manufacturer LD-DIDACTIC, coupled to a multichannel analyzer (AMC) using a Cassy Lab software. Thus, the specific activity of the primordial radionuclides 226Ra, 232Th and 40K, was able to be determined. The average values obtained are 29.66 Bq/kg, 34.88 Bq/kg and 178.424 Bq/kg respectively for 226Ra, 232Th and 40K. All average values are below the limit values recommended by UNSCEAR. However, we evaluated the radiological parameters such as the equivalent radium activity and the annual effective dose in order to translate the specific activity in terms of harmfulness. Values obtained for these parameters are below those recommended by ICRP and UNSCEAR. These results show that the risk incurred by the use of these different brands of cement is low.

Total Indicative Dose Determination in Water from the North Riviera Well Field of SODECI in Abidjan, Cote d’Ivoire

The Uranium-238 (238U), Thorium-232 (232Th) families and Potassium-40 (40K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of 238U, 232Th and 40K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides238U, 232Th, and 40K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.

SiC探测器的中子和γ性能测试

第三代SiC半导体探测器具有体积小、响应时间快、中子/伽马(n/γ)甄别容易等优点,广泛应用于反应堆堆芯剂量监测。本文针对自研的第三代SiC半导体探测器,采用电子束蒸发真空镀膜的技术将中子转换层材料^(6)LiF(^(6)Li丰度为95%)喷镀到SiC基底上,厚度为25μm,实现了中子转换层厚度优化。利用^(241)Amα放射源(活度9.37×10^(3)Bq)开展α粒子响应信号幅度的测量,并在^(137)Csγ放射源(活度6.23×10^(7)Bq)环境下开展γ射线的响应测试。另外,在标准辐射场系统中进行了SiC探测器的中子注量率响应线性度测量、γ剂量率响应线性度测量以及中子注量率响应线性标定。结果表明:该探测器在1×10^(3)~1×10^(6)cm^(−2)·s^(−1)中子注量率范围内线性响应拟合R^(2)=0.9969,具有良好的线性响应,n/γ剂量响应范围为0.005~20 Gy∙h^(−1),可用于核电现场反应堆中子和γ剂量的实时、精确监测。

成都地铁环境氡浓度与γ辐射水平调查研究

为掌握成都市地铁环境空气中氡浓度水平和γ辐射污染状况。采用固体径迹蚀刻法和瞬时测量法分别对成都地铁站内氡浓度水平和γ辐射水平开展调查研究,并对测量数据比较分析。成都地铁氡浓度测量结果范围为(9.7~32.5)Bq/m^(3),均值为(18.3±4.3)Bq/m^(3),相较国内其它城市地铁站内氡浓度偏低;成都地铁站内γ剂量率范围为(74.9~82.6)nSv/h,均值为(78.8±1.0)nSv/h,低于成都地区室内环境γ剂量率均值。估算出地铁工作人员因地铁环境氡吸入与γ辐射照射所致年有效剂量约0.30 mSv,远低于标准限值。调查研究表明成都地铁环境中的氡浓度和γ辐射水平不会对地铁工作人员造成额外的辐射危害。

血清γ⁃氨基丁酸、氧化应激与血脂异常的剂量⁃反应关系研究

目的:探讨γ‑氨基丁酸(GABA)、氧化应激指标与血脂异常患病风险的剂量‑反应关系,为预防及改善血脂异常提供参考依据。方法:选择2022年8月~2023年8月于海口市某三甲医院住院的149例血脂异常者为病例组,236例血脂正常者为对照组,通过问卷收集研究对象的基本情况,试剂盒测血清GABA水平、超氧化物歧化酶(SOD)活性、谷胱甘肽过氧化物酶(GSH‑Px)活性和丙二醛(MDA)水平。将GABA和氧化应激指标(SOD、GSH‑Px、MDA)按对照组四分位水平从低到高分为4组(Q1组~Q4组),Logistic回归分析血脂异常的患病风险;Spearman相关系数、广义线性模型和限制性立方样条分析GABA与氧化应激指标的相关性,GABA、氧化应激指标与血脂异常的剂量‑反应关系。结果:调整混杂因素后,Logistic回归显示:与Q1组SOD活性、GSH‑Px活性和MDA水平相比,Q4组血脂异常患病风险分别为OR=0.537[95%CI(0.294~0.980)]、OR=0.400[95%CI(0.213~0.750)]和OR=2.375[95%CI(1.254~4.495)](P<0.05)。GABA水平与SOD、GSH‑Px活性呈正相关,与MDA水平呈负相关(P<0.001)。广义线性模型和限制性立方样条显示:血脂异常患病风险随SOD、GSH‑Px活性增加而降低,随MDA水平增加而上升,为线性剂量‑反应关系(P<0.05)。结论:GABA水平与SOD活性、GSH‑Px活性、MDA水平存在相关性,SOD活性、GSH‑Px活性、MDA水平与血脂异常患病风险存在线性剂量‑反应关系。

不同剂量丙种球蛋白治疗小儿川崎病的临床效果

目的分析不同剂量丙种球蛋白治疗小儿川崎病的临床效果。方法回顾我院2020年3月至2022年3月收治的68例川崎病患儿的病例资料,所有患儿均在常规阿司匹林用药基础上增加丙种球蛋白治疗,根据丙种球蛋白治疗剂量将其分为低剂量组(34例,以1.0 g/kg丙种球蛋白治疗)和高剂量组(34例,以2.0 g/kg丙种球蛋白治疗)。比较两组的治疗效果。结果高剂量组的治疗总有效率高于低剂量组(P<0.05)。高剂量组的发热、黏膜弥漫性充血、躯干红斑、颈淋巴结肿胀、咽喉充血消除时间短于低剂量组(P<0.05)。治疗后,高剂量组的凝血酶时间(TT)、凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)长于低剂量组,纤维蛋白原(FIB)水平低于低剂量组(P<0.05)。治疗后,高剂量组的肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、C反应蛋白(CRP)、降钙素原(PCT)、白细胞计数(WBC)水平低于低剂量组(P<0.05)。两组的不良反应总发生率比较,差异无统计学意义(P>0.05)。结论高剂量丙种球蛋白治疗小儿川崎病的效果较好,且安全性较高,值得推广。

大剂量丙种球蛋白、阿司匹林联合甲泼尼龙治疗小儿川崎病的效果分析

目的:分析大剂量丙种球蛋白、阿司匹林联合甲泼尼龙治疗小儿川崎病的效果。方法:选取2018年10月—2022年10月兰州市西固区人民医院收治的小儿川崎病患者80例作为研究对象,依据随机数字表法分为对照组与试验组,各40例。对照组给予丙种球蛋白、阿司匹林治疗,试验组在对照组基础上应用甲泼尼龙治疗。比较两组治疗效果。结果:试验组治疗总有效率高于对照组,差异有统计学意义(P=0.013)。试验组黏膜充血改善时间、手足水肿改善时间、淋巴结消退时间、高热改善时间早于对照组,住院时间短于对照组,差异有统计学意义(P<0.001)。治疗后,两组白细胞计数、红细胞沉降率、C反应蛋白水平低于治疗前,且试验组低于对照组,差异有统计学意义(P<0.05)。结论:大剂量丙种球蛋白、阿司匹林联合甲泼尼龙治疗小儿川崎病的效果显著,能够促进症状恢复,缩短住院时间,改善实验室检查指标,值得临床推广。

宫颈癌调强放射治疗三维在体剂量验证分析及最佳γ通过率阈值

目的:对宫颈癌调强放射治疗(IMRT)进行基于电子射野影像装置的三维在体剂量验证(EIVD)分析,研究测量剂量与计划剂量间的差异,并通过剂量学敏感性探讨EIVD质控中最佳γ通过率阈值。方法:回顾性分析浙江大学医学院附属妇产科医院行IMRT的45例宫颈癌患者,所有患者在治疗过程中行EIVD验证,获取测量剂量。采用2mm/2%、2mm/3%、3mm/3%的全局γ指标进行通过率分析,采用剂量体积直方图参数评估测量剂量和计划剂量之间的差异。通过皮尔逊(Pearson)相关性分析研究γ通过率与剂量学差异间的相关性,绘制受试者工作特征(ROC)曲线确定最佳γ通过率阈值。结果:3类γ指标2mm/2%、2mm/3%、3mm/3%的平均通过率分别为(83.07±5.25)%、(91.69±3.52)%、(95.02±2.46)%;EIVD测量剂量与计划剂量在计划靶区(PTV)的平均剂量(Dmean)偏差为2.43%(P=0.016),膀胱、直肠、小肠的Dmean偏差分别为0.35%、0.46%、0.30%(P>0.05)。Pearson分析显示3类γ指标与PTV的剂量偏差相关性较强(r>0.7),与危及器官相关性较弱(r<0.7);ROC分析显示2mm/2%、2mm/3%、3mm/3%最佳的γ通过率阈值分别为79.06%、90.04%、94.19%。结论:EIVD能够有效保证宫颈癌IMRT过程中PTV剂量传递的精准性,利用γ通过率阈值能够为下一步宫颈癌自适应IMRT提供一定的临床依据。

基于ArcCheck模体放疗计划的验证与分析

目的为了保证放疗剂量输出的准确性,对放疗患者的临床放疗计划进行了验证与分析。方法选取2023年7—10月南方医科大学珠江医院放疗患者的临床放疗计划,共217例计划,其中头颈部76例,胸部82例,腹盆部59例。采用美国SunNuclear公司的ArcCheck模体,比较临床放疗计划与验证计划的剂量学差异。采用T test分析在不同容许剂量差值和不同容许距离差值下的Gamma通过率,ANOVA test比较在相同条件下,不同放疗部位放疗计划的Gamma通过率。所有数据分析采用IBM公司的SPSS v27.0完成。结果在容许剂量差值为3%,容许距离差值为3.0mm和在容许剂量差值为2%,容许距离差值为2.0mm下的Gamma通过率比较,差异有统计学意义(P<0.05)。在相同容许剂量差值和容许距离差值下,不同放疗部位的Gamma通过率比较,差异无统计学意义(P>0.05)。结论在容许剂量差值为3%,容许距离差值为3.0mm的条件下,放疗计划的Gamma通过率显著高于容许剂量差值为2%,容许距离差值为2.0mm条件下的计划Gamma通过率,并且条件设置越严格,Gamma通过率越低。在相同容许剂量差值和容许距离差值下,不同放疗部位放疗计划的Gamma通过率不存在显著性差异。Gamma通过率受容许剂量差值和距离差值的影响,同时做好对直线加速器,计划系统等的日常的质量控制与保证也能提高Gamma通过率。

利用地面γ总量转换为空气吸收剂量率进行环境辐射水平评价——以桂阳县潘家村和永兴县土桥村实测数据为例

在长期的铀矿普查中,我国积累了海量的γ总量数据资料,但应用这些数据进行放射性环境评价的研究极少。本文从γ总量和空气吸收剂量率的测量原理出发,通过梳理γ总量、放射性核素含量与空气吸收剂量率之间的关系,建立起地面γ总量与空气吸收剂量率之间的联系,分析了仪器参数对测量误差的影响,认为γ总量仪器bK/bU=2.287、bTh/bU=0.430时,测量的γ总量与空气吸收剂量率满足严格线性关系,因此γ总量仪器的bK/bU、bTh/bU值越接近这两个数值,测得的γ总量转换为空气吸收剂量率越准确;利用湖南省电离辐射计量站模型进行了γ总量转换为空气吸收剂量率的系数求解,并分析了误差,推测了仪器参数中钾的铀当量值、钍的铀当量值的大致范围;在郴州市桂阳县潘家村岩体和郴州市永兴县土桥村灰岩地区进行了γ总量、γ能谱、空气吸收剂量率的同点位实测,结果显示,当核素含量比CK/CU均值小于1、CTh/CU均值小于3时,利用γ总量(FD3013仪器测得)估算的空气吸收剂量率与利用Beck公式根据能谱估算的空气吸收剂量率的误差基本处于同等水平,均方根误差均小于15%。根据国内核素的CK/CU、CTh/CU均值,认为国内大部分地区可以利用由FD3013仪器(或类似性能仪器)测得的γ总量数据估算空气吸收剂量率。利用已有铀矿普查资料中的γ总量数据转换计算有效空气吸收剂量率,为快速大面积评估环境天然放射性外照射水平提供了方法参考。

剂量分割分阶段伽玛刀治疗紧邻视路的海绵窦海绵状血管瘤单中心回顾性研究

目的分析伽玛刀剂量分割分阶段策略治疗紧邻视路结构海绵窦海绵状血管瘤的疗效和安全性。方法分析2018年3月—2020年9月上海伽玛医院采用分阶段伽玛刀治疗紧邻视路海绵窦海绵状血管瘤11例患者的临床资料,10例为磁共振影像学诊断,1例为经鼻蝶手术后有明确的组织病理学诊断;10例女性患者,年龄27~72岁,中位年龄40岁;肿瘤体积5.54~31.00 cm^(3),中位体积15.09 cm^(3);11例患者均完成两阶段伽玛刀治疗,2次伽玛刀间隔时间3~9个月(中位8个月);第一阶段伽玛刀处方周边剂量8~10 Gy(中位8.8 Gy),等剂量线40%~50%(中位45%);第二阶段处方周边剂量8~10 Gy(中位8.8 Gy),等剂量线40%~52%(中位46%)。结果伽玛刀治疗后随访时间25~60个月(中位40个月);第二阶段伽玛刀治疗时肿瘤体积较第一阶段缩小20.3%~85.3%(中位64.2%);随访终点所有11例患者的肿瘤均得到控制(控制率100%),分阶段伽玛刀治疗后肿瘤体积较治疗前缩小70.6%~92.5%(中位83.0%);90.9%的患者(n=10)在伽玛刀治疗后临床症状消失或改善,随访中无辐射诱导的视路损伤或其他神经功能障碍的发生。结论剂量分割分阶段伽玛刀是紧邻视路结构的海绵窦海绵状血管瘤有效安全合理的治疗策略。

SRS MapCHECK与EDOSE在立体定向放疗计划剂量验证中的对比

目的:使用SRS MapCHECK和EDOSE对立体定向放疗(SRT)计划进行剂量验证,并比较它们的验证结果。方法:首先比较两种系统在不同方野(2 cm×2 cm、4 cm×4 cm、6 cm×6 cm、10 cm×10 cm)的γ通过率(3%/3 mm),然后选择29例SRT计划,分析两种系统在不同γ标准下的绝对剂量通过率,最后分析EDOSE建立的4种不同物理模型对SRT计划剂量验证的影响。结果:SRS MapCHECK在所有方野和29例SRT计划的绝对剂量γ通过率均高于EDOSE,两者的验证结果有统计学差异(P<0.05);SRS MapCHECK及EDOSE在29例SRT计划的γ通过率(2%/2 mm)分别是为98.60%±2.14%和96.53%±2.41%。基于EDOSE的不同物理模型验证结果有统计学差异,平均γ通过率(2%/2 mm)偏差为1.8%~5.1%。结论:SRS MapCHECK和EDOSE系统均满足SRT计划剂量验证的要求,且SRS MapCHECK的剂量验证通过率优于EDOSE;不同的EDOSE物理模型对SRT计划剂量验证有影响。

Enhancing Precision in Radiotherapy Delivery: Validating Monte Carlo Simulation Models for 6 MV Elekta Synergy Agility LINAC Photon Beam Using Two Models of the GAMOS Code

The most crucial requirement in radiation therapy treatment planning is a fast and accurate treatment planning system that minimizes damage to healthy tissues surrounding cancer cells. The use of Monte Carlo toolkits has become indispensable for research aimed at precisely determining the dose in radiotherapy. Among the numerous algorithms developed in recent years, the GAMOS code, which utilizes the Geant4 toolkit for Monte Carlo simula-tions, incorporates various electromagnetic physics models and multiple scattering models for simulating particle interactions with matter. This makes it a valuable tool for dose calculations in medical applications and throughout the patient’s volume. The aim of this present work aims to vali-date the GAMOS code for the simulation of a 6 MV photon-beam output from the Elekta Synergy Agility linear accelerator. The simulation involves mod-eling the major components of the accelerator head and the interactions of the radiation beam with a homogeneous water phantom and particle information was collected following the modeling of the phase space. This space was po-sitioned under the X and Y jaws, utilizing three electromagnetic physics mod-els of the GAMOS code: Standard, Penelope, and Low-Energy, along with three multiple scattering models: Goudsmit-Saunderson, Urban, and Wentzel-VI. The obtained phase space file was used as a particle source to simulate dose distributions (depth-dose and dose profile) for field sizes of 5 × 5 cm2 and 10 × 10 cm2 at depths of 10 cm and 20 cm in a water phantom, with a source-surface distance (SSD) of 90 cm from the target. We compared the three electromagnetic physics models and the three multiple scattering mod-els of the GAMOS code to experimental results. Validation of our results was performed using the gamma index, with an acceptability criterion of 3% for the dose difference (DD) and 3 mm for the distance-to-agreement (DTA). We achieved agreements of 94% and 96%, respectively, between simulation and experimentation for the three electromagnetic physics models and three mul-tiple scattering models, for field sizes of 5 × 5 cm2 and 10 × 10 cm2 for depth-dose curves. For dose profile curves, a good agreement of 100% was found between simulation and experimentation for the three electromagnetic physics models, as well as for the three multiple scattering models for a field size of 5 × 5 cm2 at 10 cm and 20 cm depths. For a field size of 10 × 10 cm2, the Penelope model dominated with 98% for 10 cm, along with the three multiple scattering models. The Penelope model and the Standard model, along with the three multiple scattering models, dominated with 100% for 20 cm. Our study, which compared these different GAMOS code models, can be crucial for enhancing the accuracy and quality of radiotherapy, contributing to more effective patient treatment. Our research compares various electro-magnetic physics models and multiple scattering models with experimental measurements, enabling us to choose the models that produce the most reli-able results, thereby directly impacting the quality of simulations. This en-hances confidence in using these models for treatment planning. Our re-search consistently contributes to the progress of Monte Carlo simulation techniques in radiation therapy, enriching the scientific literature.

桂阳潘家庄地区地表γ辐射空气吸收剂量率估算与放射性环境评价

桂阳潘家庄地区花岗岩大面积出露,导致土壤中的放射性核素活度浓度普遍偏高。较高的γ辐射空气吸收剂量是否存在风险成为人们关心的问题。本文通过已有γ伽玛能谱测量数据估算出地表γ辐射空气吸收剂量率,根据地表γ辐射空气吸收剂量率与人居环境适宜性的关系,从而进行人居环境适宜性分区。得出γ辐射安全区197.90 km^(2),占全区面积的98.95%;风险区1.42 km^(2),占0.71%;管制区仅0.68 km^(2);表明潘家庄地区天然放射性人居环境优良。本文可为该地区人居环境选址、合理、有效地利用潘家庄地区的国土资源提供支持,也可对加速潘家庄地区乡村健康与可持续发展提供必要的参考。