Design of synchrotron for hadron therapy

According to the operation and development of radiation therapy in the world, in order to further promote the radiation therapy of tumour in China, a design of a special synchrotron with two super-periodicity for hadron therapy is presented, including lattice, injection system, RF acceleration and slow extraction of the third order resonance. The synchrotron accelerates the proton beam to 250MeV and the carbon beam to 4000MeV/u.

Heavy-ion conformal irradiation in the shallow-seated tumor therapy terminal at HIRFL

Basic research related to heavy-ion cancer therapy has been done at the Institute of Modern Physics (IMP), Chinese Academy of Sciences since 1995. Now a plan of clinical trial with heavy ions has been launched at IMP. First, superficially placed tumor treatment with heavy ions is expected in the therapy terminal at the Heavy Ion Research Facility in Lanzhou (HIRFL), where carbon ion beams with energy up to 100 MeV/u can be supplied. The shallow-seated tumor therapy terminal at HIRFL is equipped with a passive beam delivery system including two orthogonal dipole magnets, which continuously scan pencil beams laterally and generate a broad and uniform irradiation field, a motor-driven energy degrader and a multi-leaf collimator. Two different types of range modulator, ripple filter and ridge filter with which Guassian-shaped physical dose and uniform biological effective dose Bragg peaks can be shaped for therapeutic ion beams respectively, have been designed and manufactured. Therefore, two-dimensional and three-dimensional conformal irradiations to tumors can be performed with the passive beam delivery system at the earlier therapy terminal. Both the conformal irradiation methods have been verified experimentally and carbon-ion conformal irradiations to patients with superficially placed tumors have been carried out at HIRFL since November 2006.

Capability verification of the beam delivery system in the superficially-placed tumor therapy terminal at HIRFL

The passive beam delivery system in the superficially-placed tumor therapy terminal at Heavy Ion Researc h Facility in Lanzhou (HIRFL), which includes two orthogonal dipole magnets as scanning system, a motor-driven energy degrader as range-shifter, series of ridge filters as range modulator and a multileaf collimator, is introduced in detail. The capacities of its important components and the whole system have been verified experimentally. The tests of the ridge filter for extending Bragg peak and the range shifter for energy adjustment show both work well. To examine the passive beam delivery system, a beam shaping experiment were carried out, simulating a three-dimensional (3D) conformal irradiation to a tumor. The encouraging experimental result confirms that 3D layer-stacking conformal irradiation can be performed by means of the passive system. The validation of the beam delivery system establishes a substantial basis for upcoming clinical trial for superficially-placed tumors with heavy ions in the therapy terminal at HIRFL.

Pre-irradiation with low-dose C-12(6+) beam significantly enhances the efficacy of AdCMV-p53 gene therapy in human non-small lung cancer

The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in C-12(6+) beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in gamma-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G(0)/G(1) arrest and activated G(2)/M checkpoints. The pre-exposure to C-12(6+) beam significantly improved cell to apoptosis. RBEs for the C-12(6+)+ AdCMV-p53 infection groups were 30%-60%,20% -130% and 30%-70% more than those for the C-12(6+)_irradiated only, AdCMV-p53 infected only, and gamma-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose C-12(6+) beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.

Physical property measurement of therapeutic carbon ion beam in the shallow-seated tumor therapy terminal at HIRFL

For the first time the physical properties of therapeutic carbon-ion beam supplied by, the shallow-seated tumor therapy terminal at the Heavy Ion Research Facility in Lanzhou (HIRFL) are measured. For a 80.55MeV/u C-12 ion beam delivered to the therapy terminal, the homogeneity of irradiation fields is 73.48%, when the beam intensity varied in the range of 0.001-0.1nA (i.e. 1 X 10(6) - 1 X 10(8) particles per second). The stability of the beam intensity within a few minutes is estimated to be 80.87%. The depth-dose distribution of the beam at the isocenter of the therapy facility is measured, and the position of the high-dose Bragg peak is found to be located at the water-equivalent depth of 13.866mm. Based on the relationship between beam energy and Bragg peak position, the corresponding beam energy at the isocenter of the therapy terminal is evaluated to be 71.71MeV/u for the original 80.55MeV/u C-12 ion beam, which consisted basically with calculation. The readout of the previously-used air-free ionization chamber regarding absorbed dose is calibrated as well in this experiment. The results indicate that the performance of the therapy facility should be optimized further to meet the requirements of clinical trial.

An online monitor ionization chamber used in particle therapy

The clinical trials of tumor therapy using heavy ions beam C-12 are now in progress at Institute of Modem Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy C-12 beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy C-12 beam in active pencil beam scanning mode.

重离子治癌相关研究；Researches Related to Heavy Ion Cancer Therapy

癌症是现代医学的难题,一直危害着人类的健康。放射治疗是癌症治疗的有效手段之一。由于重离子束在物理学和生物学性质上所具有的优势,它已成为放疗用的最佳射线。简述了重离子治癌的发展历程、现状以及特点,详细讨论了在医学物理和放射生物学研究领域值得关注的若干热点问题。

兰州重离子治癌研究装置的准直测量技术；Survey and alignment for the heavy ion therapy facility at IMP

介绍了中国科学院近代物理研究所重离子治癌装置的安装定位测量技术和方法。利用激光跟踪仪通过控制网的建立,和多重坐标系的转换,使最后的磁铁安装径向相对误差不超过±(0.05-0.1)mm,真空管道的横向及竖向精度也达到了±(0.1-0.2)mm。

Neutron dose measurement in carbon ion radiation therapy at HIRFL (IMP)

For radiation protection purposes, the neutron dose in carbon ion radiation therapy at the HIRFL (Heavy Ion Research Facility in Lanzhou) was investigated. The neutron dose from primary C-12 ions with a specific energy of 100 MeV/u delivered from SSC was roughly measured with a standard Anderson-Broun rem-meter using a polyethylene target at various distances. The result shows that a maximum neutron dose contribution of 19 mSv in a typically surface tumor treatment was obtained, which is less than 1% of the planed heavy ion dose and is in reasonable agreement with other reports. Also the gamma-ray dose was measured in this experiment using a thermo luminescent detector.

Antifungal Activity of Quaternized Carboxymethyl Chitosan

Quaternized carboxymethyl chitosan (QCMC) were synthesized and their antifungal activities against Alternaria Solani (A. Solani) and Physalospora piricola Nose (P. piricola Nose) were investigated. The results indicated that the quaternized carboxymethyl chitosan derivatives had better inhibitory effects than CMC, and the antifungal activities should be affected by the cation in these compounds.

Preparation, characterization and antifungal properties of 2-(alpha-arylamino phosphonate)-chitosan

In this paper, 20 kinds of different 2-(alpha-arylamino phosphonate)-chitosan (2-alpha-AAPCS) were prepared by different Schiff bases of chitosan (CS) reacted with di-alkyl phosphite in benzene solution. The structures of the derivatives (2-alpha-AAPCS) were characterized by FT-IR spectroscopy and elemental analysis. In addition, the antifungal activities of the derivatives against four kinds of fungi were evaluated in the experiment. The results indicated that all the prepared 2-alpha-AAPCS had a significant inhibiting effect on the investigated fungi when the derivatives concentration ranged from 50 to 500 mu g mL(-1). Furthermore, the antifungal activities of the derivatives increased with increasing the molecular weight and concentration. And the antifungal activities of the derivatives were affected by their dimensional effect and charge density. Besides, the rule and mechanism of the antifungal activities of them were discussed in this paper. (C) 2009 Elsevier B.V. All rights reserved.

Antifungal properties of Schiff bases of chitosan, N-substituted chitosan and quaternized chitosan

Schiff bases of chitosan, N-substituted chitosan, and quaternized chitosan were synthesized and their antifungal properties were analyzed against Botrytis cinerea Pers. (B. cinerea pers.) and Colletotrichum lagenarium (Pass) Ell.et halst (C. lagenarium (Pass) Ell.et halst) based on the method of D. Jasso de Rodriguez and co-workers. The results showed that quaternized chitosan had better inhibitory properties than chitosan, Schiff bases of chitosan, and N-substituted chitosan. (c) 2007 Elsevier Ltd. All rights reserved.

The influence of molecular weight of quaternized chitosan on antifungal activity

Quaternized chitosan derivatives with different molecular weights were synthesized in the laboratory. Subsequent experiments were conducted to test their antifungal activities against Botrytis cinerea Pers. (B. cinerea pers.) and Colletotrichum lagenarium (Pass) Ell.et halst (C. lagenarium (Pass) EII.et halst). Our results indicate that quaternized chitosan derivatives have stronger antifungal activities than chitosan. Furthermore, quaternized chitosan derivatives with high molecular weight are shown to have even stronger antifungal activities than those with low molecular weight. (c) 2007 Published by Elsevier Ltd.

The influence of the cationic of quaternized chitosan on antifungal activity

Quatemized chitosan: N-(2-hydroxyl-phenyl)-NN-dimethyl chitosan (NHPDCS), N-(5-chloro-2-hydroxyl-phenyl)-NN-dimethyl chitosan (NCHPDCS), N-(2-hydroxyl-5-nitro-phenyl)-NN-dimethyl chitosan (NHNPDCS) and N-(5-bromic-2-hydroxyl-phenyl)-NN-dimethyI chitosan (NBHPDCS) were synthesized and their antifungal activities against Botrytis cinerea Pers. (B. cinerea Pers.) and Colletotrichum lagenarium (Pass) Ell.et halst (C. lagenarium (Pass) Ellet halst) were investigated. The results indicated that the quaternized chitosan derivatives had better inhibitory effects than chitosan, and the antifungal activities should be affected by the cation in these compounds. (C) 2007 Elsevier B.V. All rights reserved.

Synthesis and antifungal properties of sulfanilamide derivatives of chitosan

Sulfanilamide derivatives of chitosan (2-(4-acetamido-2-sulfanimide)-chitosan (HSACS, LSACS), 2-(4-acetamido-2-sulfanimide)-6-sulfo-chitosan (HSACSS, LSACSS) and 2-(4-acetamido-2-sulfanimide)-6-carboxymethyl-chitosan (HSACMCS, LSACMCS)) were prepared using different molecular weights of chitosan (CS), carboxymethyl chitosan (CMCS) and chitosan sulfates (CSS) reacted with 4-acetamidobenzene sulfonyl chloride in dimethylsulfoxide solution. The structures of the derivatives were characterized by FT-IR spectroscopy and elemental analysis, which showed that the substitution degree of sulfanilamide group of HSACS, HSACSS, HSACMCS, LSACS, LSACSS and LSACMCS were 0.623, 0.492, 0.515, 0.576, 0.463 and 0.477, respectively. The solubility of the derivatives (pH < 7.5) was higher than that of chitosan (pH < 6.5). The antifungal activities of the derivatives against Aiternaria solani and Phomopsis asparagi were evaluated based on the method of Jasso et al. in the experiment. The results indicated that all the prepared sulfanilamide derivatives had a significant inhibiting effect on the investigated fungi in the polymer concentration range from 50 to 500 mu g mL(-1). The antifungal activities of the derivatives increased with increasing the molecular weight, concentration or the substitution degree. The sulfanilamide derivatives of CS, CMCS and CSS show stronger antifungal activities than CS, CMCS and CSS. (C) 2007 Elsevier Ltd. All rights reserved.