Alkaline earth sulfides (MgS,CaS and BaS) crystal doped with rare-earth ions is an optically stimulated luminescence dosimeter with very high sensitivity,short time constant of the optically stimulated luminescence (O...Alkaline earth sulfides (MgS,CaS and BaS) crystal doped with rare-earth ions is an optically stimulated luminescence dosimeter with very high sensitivity,short time constant of the optically stimulated luminescence (OSL) separated perfectly from the stimulation.In this paper,an OSL dosimeter is described.It has linear dose response from 0.01 to 1000 Gy.The equipment,relatively simple and small in size is promising for applications in space exploration and for high dose irradiation and dangerous irradiation conditions.展开更多
Measurements of radiation dose to patients in spiral computed tomography (CT) were completed for various collimations,table speeds and pitch. A standard CT head dosimetry phantom and thermoluminescent dosime- ters (TL...Measurements of radiation dose to patients in spiral computed tomography (CT) were completed for various collimations,table speeds and pitch. A standard CT head dosimetry phantom and thermoluminescent dosime- ters (TLD) were used for the measurement. The effect of collimation and pitch on radiation dose was studied. The results indicated that the radiation dose at the given tube current,voltage and rotation speed was inversely propor- tional to pitch. And the increasing times of dose were as decreasing times of pitch. This regular pattern was tenable for radiation dose at both central holes and peripheral holes of the phantom at pitch = 1,>1 and <1. The collimation had no impact on the radiation dose. The results also indicated that radiation dose at central holes was nearly equal to that at peripheral holes. There was no significant difference between them statistically. The study demonstrates that the pitch in spiral CT scans is the primary parameter and has significant impact on radiation dose.展开更多
A Fricke-PVA-xylenol orange (FPX) hydrogel dosimeter, in good transparency, was prepared by physical crosslinking for three-dimensional dose measurements. The process of mixing the chemical dosimeter with the PVA solu...A Fricke-PVA-xylenol orange (FPX) hydrogel dosimeter, in good transparency, was prepared by physical crosslinking for three-dimensional dose measurements. The process of mixing the chemical dosimeter with the PVA solution was carried out at room temperature, which reduced the influence of auto-oxidation rate. Gradation in color was obviously observed with different distance from the radiation source after 6 MeV electron beam irradiation for radiotherapy. The effects of irradiation dose and three components of the FPX gel dosimeter, i.e. ferrous ions, xylenol orange (XO) and sulphuric acid on sensitivity and stability of dose response were investigated by UV-vis spectropho-tometric measurement. The dose response of the FPX gel dosimeter was linear in the range 0~2.0 Gy. The orthogonal test was employed to find the optimal composition of the gel dosimeter with a sensitivity of about 0.095 cm-1·Gy-1. It was found that XO concentration greatly affected the sensitivity of dose response and lower concentrations of the ferrous ion and XO gave higher sensitivity within the range 0~2.0 Gy.展开更多
A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was bette...A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was better in reproducibility and accuracy. Using this method, we found telomerase activities were absent in normal human liver cells, while detected in ail of four human hepatoma cell lines (BEL-7404, SMMC-7721, QGY-7903 and HCCM) without significant differences.展开更多
For TBI (total body irradiation) prior to BMT(bone marrow transplantation )and in order to guarantee exact treatment,it is necessary to perfect in vivo dosimetry to detect any deviation of the treatment and to verify ...For TBI (total body irradiation) prior to BMT(bone marrow transplantation )and in order to guarantee exact treatment,it is necessary to perfect in vivo dosimetry to detect any deviation of the treatment and to verify the dose dis-tribution. A simplified and convenient transmission type in vivo dosimetry and problems are introduced and discussed.展开更多
In the prostate cancer treatment, brachytherapy with iodine-125 seeds has been used. lodine-125 seeds are sealed radioactive sources, made by a titanium capsule containing the radioisotope inside. In the final phase o...In the prostate cancer treatment, brachytherapy with iodine-125 seeds has been used. lodine-125 seeds are sealed radioactive sources, made by a titanium capsule containing the radioisotope inside. In the final phase of the seeds production, it is necessary to ensure that there is no leakage of the radioactive material. A leakage test is performed, immersing the seeds in water during 24 h and measuring the resulting activity in the water. This measurement is made in a sodium iodide detector. The immersion water is transferred to a plastic tube with a cap. The tube is placed by an automated positioning system, in the detector chamber. This study aims to determine the best positioning of the tube for the detection. It is also important to determine the influence of the positioning variation intrinsic of the automated positioning system during the iodine-125 seeds production. The results obtained will be used as a reference to adjust the equipment and process control system, in the production of the iodine-125 seeds.展开更多
基金National Natural Science Foundation of China (10475112)Western Light Foundation of 2005 years
文摘Alkaline earth sulfides (MgS,CaS and BaS) crystal doped with rare-earth ions is an optically stimulated luminescence dosimeter with very high sensitivity,short time constant of the optically stimulated luminescence (OSL) separated perfectly from the stimulation.In this paper,an OSL dosimeter is described.It has linear dose response from 0.01 to 1000 Gy.The equipment,relatively simple and small in size is promising for applications in space exploration and for high dose irradiation and dangerous irradiation conditions.
文摘Measurements of radiation dose to patients in spiral computed tomography (CT) were completed for various collimations,table speeds and pitch. A standard CT head dosimetry phantom and thermoluminescent dosime- ters (TLD) were used for the measurement. The effect of collimation and pitch on radiation dose was studied. The results indicated that the radiation dose at the given tube current,voltage and rotation speed was inversely propor- tional to pitch. And the increasing times of dose were as decreasing times of pitch. This regular pattern was tenable for radiation dose at both central holes and peripheral holes of the phantom at pitch = 1,>1 and <1. The collimation had no impact on the radiation dose. The results also indicated that radiation dose at central holes was nearly equal to that at peripheral holes. There was no significant difference between them statistically. The study demonstrates that the pitch in spiral CT scans is the primary parameter and has significant impact on radiation dose.
基金Supported by Municipal Commission of Science and Technology of Shanghai (08JC1410200)Shanghai Leading Academic Discipline Project (S30109)
文摘A Fricke-PVA-xylenol orange (FPX) hydrogel dosimeter, in good transparency, was prepared by physical crosslinking for three-dimensional dose measurements. The process of mixing the chemical dosimeter with the PVA solution was carried out at room temperature, which reduced the influence of auto-oxidation rate. Gradation in color was obviously observed with different distance from the radiation source after 6 MeV electron beam irradiation for radiotherapy. The effects of irradiation dose and three components of the FPX gel dosimeter, i.e. ferrous ions, xylenol orange (XO) and sulphuric acid on sensitivity and stability of dose response were investigated by UV-vis spectropho-tometric measurement. The dose response of the FPX gel dosimeter was linear in the range 0~2.0 Gy. The orthogonal test was employed to find the optimal composition of the gel dosimeter with a sensitivity of about 0.095 cm-1·Gy-1. It was found that XO concentration greatly affected the sensitivity of dose response and lower concentrations of the ferrous ion and XO gave higher sensitivity within the range 0~2.0 Gy.
文摘A non-radioisotopic, quantitative TRAP-based telomerase activity assay was established mainly by using SYBR Green-I staining instead of radioisotope. Comparing with conventional radioisotope based method, it was better in reproducibility and accuracy. Using this method, we found telomerase activities were absent in normal human liver cells, while detected in ail of four human hepatoma cell lines (BEL-7404, SMMC-7721, QGY-7903 and HCCM) without significant differences.
文摘For TBI (total body irradiation) prior to BMT(bone marrow transplantation )and in order to guarantee exact treatment,it is necessary to perfect in vivo dosimetry to detect any deviation of the treatment and to verify the dose dis-tribution. A simplified and convenient transmission type in vivo dosimetry and problems are introduced and discussed.
文摘In the prostate cancer treatment, brachytherapy with iodine-125 seeds has been used. lodine-125 seeds are sealed radioactive sources, made by a titanium capsule containing the radioisotope inside. In the final phase of the seeds production, it is necessary to ensure that there is no leakage of the radioactive material. A leakage test is performed, immersing the seeds in water during 24 h and measuring the resulting activity in the water. This measurement is made in a sodium iodide detector. The immersion water is transferred to a plastic tube with a cap. The tube is placed by an automated positioning system, in the detector chamber. This study aims to determine the best positioning of the tube for the detection. It is also important to determine the influence of the positioning variation intrinsic of the automated positioning system during the iodine-125 seeds production. The results obtained will be used as a reference to adjust the equipment and process control system, in the production of the iodine-125 seeds.
