高剂量水平吸收剂量测量用辐射变色薄膜剂量计研究

为建立制备高剂量水平吸收剂量测量的辐射变色薄膜剂量计的方法,对相应的配方及制备工艺进行研究,批量制备了以尼龙为基材,副品红氰化物为染料的辐射变色薄膜剂量计。在60 Coγ参考辐射场中对辐射变色薄膜的各剂量学响应性能进行了研究,结果表明,重复性好于1.0%,在5~210kGy剂量范围内具有较好的剂量响应线性,辐射变色薄膜剂量计辐照后置于低温条件下贮存2周内信号较稳定。此外,该辐射变色薄膜剂量计在本实验范围内未发现明显的剂量率依赖性。通过上述剂量学性能研究,在线性剂量范围内,测量吸收剂量的扩展不确定度为4.2%(k=2)。通过在加速器上进一步实验表明,该膜可用于电子束辐照参数测量。     

辐射变色薄膜剂量计的研制

以尼龙为基材、六羟基乙基副品红氰化物（hexahydroxyethylpararosanilinecyanide,HPR-CN）为染料研制辐射变色薄膜剂量计。文章描述了该剂量计的工作原理、配方、物理性能及其剂量学性能测试结果。实验测试表明,自制的辐射变色薄膜剂量计具有较好的剂量学性能。文章对自制的辐射变色薄膜剂量计的性能与FWT-60辐射变色薄膜剂量计的性能进行了比较。     

批制辐射加工用辐射变色薄膜剂量性能研究

以尼龙为基材、副品红氰化物为染料制备了辐射变色薄膜剂量计,并在⁶⁰Co γ射线及10 MeV电子束参考辐射场中对辐射变色薄膜的各剂量学响应性能进行了研究。研究结果表明,在1~210 kGy剂量范围内,该辐射变色薄膜剂量计具有较好的剂量响应线性,且在本实验范围内未发现明显的能量和剂量率依赖性;该剂量计重复性好于1.0%,照射后置于低温条件下贮存2周内信号较稳定;在1~210 kGy剂量线性范围内得到的辐射变色薄膜剂量计测量吸收剂量的扩展不确定度对⁶⁰Co γ射线为4.4%（k=2）,对电子束为6.2%（k=2）。通过在加速器上进一步的实验表明,该辐射变色薄膜除可用于辐射加工中剂量监测外,还可用于电子束辐照参数的测量。     

NF-86、NF-87与FWT-60三种辐射变色染料尼龙薄膜剂量计性能的比较研究

NF-86和NF-87两种剂量计均是以尼龙为基质材料,分别以六羟乙基付品红氰化物和付品红氰化物为辐射变色染料的薄膜剂量计。本文给出这两种剂量计与国外同类产品——美国远西公司的FWT-60辐射变色尼龙薄膜剂量计主要剂量学性能比较研究的结果。结果表明NF-86、NF-87剂量计的性能已接近和达到美国FWT-60剂量计的水平,能够为国内辐射加工中γ剂量测量(10~3—10~5Gy)提供一种简便快速而又可靠的监测手段。     

以PVB为基材的低剂量辐射变色薄膜剂量计研究

研制了一种具有低剂量响应特征的辐射变色薄膜,剂量范围从几十至若干个千戈瑞。选用隐色孔雀绿(LMG)为染料,以聚乙烯缩丁醛(polyvinyl butyral,PVB)为基材制备辐射变色薄膜剂量计,该剂量计经几百Gy剂量辐照后颜色从无色变成深绿色,利用钴源对该种辐射变色薄膜剂量计的剂量学性能进行了研究,结果表明,该剂量计具有较好的剂量响应线性特性和较大的剂量响应范围(20~6 500Gy),可用于血液辐照、食品辐照和环境辐射监测等更多领域。     

辐射加工标签剂量计的初步研究

为了有效监测⁶⁰Co γ射线及电子束参考辐射场中被照产品所受的吸收剂量,本工作研制了一种标签剂量计,用于辐射加工中吸收剂量的快速、简单测量。标签剂量计具有多层复合结构,核心部分是一层辐射变色薄膜,主要成分为聚乙烯醇、酸敏染料和卤素化合物。对该辐射变色薄膜剂量计的剂量学性能进行了分析研究,结果表明,该薄膜剂量计可以满足日常辐照监测的需要。     

二醋酸纤维素薄膜剂量计的制备和性能研究

为了改善醋酸纤维素薄膜剂量计在γ辐射剂量测定中稳定性欠佳的问题,拓展其辐射测量应用范围,采用离子液体均相乙酰化纤维素方法制得的二醋酸纤维素（CDA）粉末为原料,优化CDA薄膜制备工艺,研究其γ辐射变色性能及稳定性,制备适用于γ辐射剂量测量且性能优良的CDA薄膜剂量计。基于CDA的辐射变色机理,该薄膜剂量计在270 nm的单位厚度吸光度与吸收剂量存在良好的线性关系,剂量率、CDA的取代度和辐照气氛对薄膜的工作曲线影响较小。CDA薄膜剂量计的剂量检测量程为50~400 kGy,扩展不确定度为8.8%（K=2）,辐照后24 h内吸光度测试稳定,具有良好的辐照稳定性,基本满足工业上对于辐射剂量计的使用要求,有望应用于γ辐射剂量的测量。     

二醋酸纤维素薄膜剂量计的制备和性能研究

为了改善醋酸纤维素薄膜剂量计在γ辐射剂量测定中稳定性欠佳的问题,拓展其辐射测量应用范围,采用离子液体均相乙酰化纤维素方法制得的二醋酸纤维素(CDA)粉末为原料,优化CDA薄膜制备工艺,研究其γ辐射变色性能及稳定性,制备适用于γ辐射剂量测量且性能优良的CDA薄膜剂量计。基于CDA的辐射变色机理,该薄膜剂量计在270 nm的单位厚度吸光度与吸收剂量存在良好的线性关系,剂量率、CDA的取代度和辐照气氛对薄膜的工作曲线影响较小。CDA薄膜剂量计的剂量检测量程为50～400 kGy,扩展不确定度为8.8%(K=2),辐照后24 h内吸光度测试稳定,具有良好的辐照稳定性,基本满足工业上对于辐射剂量计的使用要求,有望应用于γ辐射剂量的测量。     

GD-300系列辐射光致发光玻璃剂量计的辐射剂量学特性

为掌握新引进的辐射光致发光玻璃剂量计的辐射剂量学特性,通过用次级标准剂量学实验室的X射线照射装置、⁶⁰Coγ放射源（1250keV）及经检定的¹³⁷Csγ放射源（662keV）照射,考察了GD-300系列辐射光致发光玻璃剂量计的剂量线性、均匀性、重复性、衰退特性和能量响应等剂量学性能。实验研究结果表明,GD-300系列辐射光致发光玻璃剂量计的辐射剂量学性能良好,适合作为放射工作人员外照射剂量、放射诊疗受检者与患者剂量的测量,也适用于环境辐射的长期累积测量。     

辐射变色薄膜剂量计配方研究

叙述了选用进口的和国产的六羟基乙基副品红氰化物染料(HPR-CN)及副品红氰化物染料(PR-CN)以尼龙为基材制成辐射变色薄膜剂量计的配方研究。对四种染料膜的性能进行了详细的试验和比较。通过物理性能测试和剂量学性能测试,为批制辐射变色薄膜剂量计的研制确定了最佳基材、染料和配方。     

Mycosis Fungoides electron beam absorbed dose distribution using Fricke xylenol gel dosimetry

Radiotherapy uses ionizing radiation to destroy tumor cells. The absorbed dose control in the target volume is realized through radiation sensors, such as Fricke dosimeters and radiochromic film, which permit to realize bi-dimensional evaluations at once and because of that, they will be used in this study as well. Among the several types of cancer suitable for ionizing radiation treatment, the Mycosis Fungoides, a lymphoma that spreads on the skin surface and depth, requires for its treatment total body irradiation by high-energy electrons. In this work the Fricke xylenol gel (FXG) was used in order to obtain information about the absorbed dose distribution induced by the electron interactions with the irradiated tissues and to control this type of treatment. FXG can be considered as an alternative dosimeter, since up to now only films have been used. FXG sample cuvettes, simulating two selected tomos (cranium and abdomen) of the Rando anthropomorphic phantom, were positioned along with radiochromic films for comparison. The phantom was subjected to Stanford total body irradiation using 6 MeV electrons. Tomographic images were acquired for both dosimeters and evaluated through horizontal and vertical profiles along the tomographic centers. These profiles were obtained through a Matlab routine developed for this purpose. From the obtained results, one could infer that, for a superficial and internal patient irradiation, the FXG dosimeter showed an absorbed dose distribution similar to the one of the film. These results can validate the FXG dosimeter as an alternative dosimeter for the Mycosis Fungoides treatment planning.     

Evaluation of dosimetric functions for Ir-192 source using radiochromic film

Ir-192 source is widely used in high dose rate brachytherapy. The aim of this study was to derive the brachytherapy dosimetric functions described in AAPM TG-43 to characterize the dosimetric properties of commercially available microselectron HDR Ir-192 source. All the measurements were carried out with GAFCHROMIC EBT radiochromic film in water equivalent solid phantom and the grey values were analyzed using Omnipro IMRT film dosimetry software with Vidar VXR-16 scanner. Optical density of the film was converted to dose using calibration film established in this study. Measurements were carried out by measuring the dose at radial distances from 0.5 cm to 5.0 cm with interval of 0.5 cm and at polar angle 0°-180° in 10° intervals. Dosimetric functions such as dose rate constant, radial dose functions and anisotropy of the dose distribution were found to be in good agreement with Monte Carlo calculations. This study confirms the feasibility of radiochromic EBT film dosimetry in characterization of the TG-43 parameters for Ir-192 HDR source.