DEVELOPED IMPROVED AND CLINICAL APPLICATION OF BIPOLAR HIP PROSTHESIS—2—13 YEARS FOLLOW—UP

ＤＥＶＥＬＯＰＥＤＩＭＰＲＯＶＥＤＡＮＤＣＬＩＮＩＣＡＬＡＰＰＬＩＣＡＴＩＯＮＯＦＢＩＰＯＬＡＲＨＩＰＰＲＯＳＴＨＥＳＩＳ—２—１３ＹＥＡＲＳＦＯＬＬＯＷ—ＵＰＤＥＶＥＬＯＰＥＤＩＭＰＲＯＶＥＤＡＮＤＣＬＩＮＩＣＡＬＡＰＰＬＩＣＡＴＩＯＮＯＦＢＩＰＯ...     

REPLACEMENT OF ARTERIES WITH ePTFE VASCULARGRAFTS LINED WITH CONFLUENT AUTOLOGOUS ENDOTHELIAL CELLS IN NON-HUMAN PRIMATES

ＲＥＰＬＡＣＥＭＥＮＴＯＦＡＲＴＥＲＩＥＳＷＩＴＨｅＰＴＦＥＶＡＳＣＵＬＡＲＧＲＡＦＴＳＬＩＮＥＤＷＩＴＨＣＯＮＦＬＵＥＮＴＡＵＴＯＬＯＧＯＵＳＥＮＤＯＴＨＥＬＩＡＬＣＥＬＬＳＩＮＮＯＮ－ＨＵＭＡＮＰＲＩＭＡＴＥＳＲＥＰＬＡＣＥＭＥＮＴＯＦＡＲＴＥＲ...     

EXPERIMENTAL STUDIES OF MEDICAL EQUIPMENT SELECTION BY USING THE MULTI-STAGE WEIGHTING EVALUATION METHOD

ＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＩＥＳＯＦＭＥＤＩＣＡＬＥＱＵＩＰＭＥＮＴＳＥＬＥＣＴＩＯＮＢＹＵＳＩＮＧＴＨＥＭＵＬＴＩ－ＳＴＡＧＥＷＥＩＧＨＴＩＮＧＥＶＡＬＵＡＴＩＯＮＭＥＴＨＯＤＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＩＥＳＯＦＭＥＤＩＣＡＬＥＱＵＩＰ...     

A NEW ANALYTICAL METHOD FOR O_2 AND CO_2 TRANSFER IN SHELL-AND-TUBE(INTRA-LUMINALFLOW)OXYGEN AT ORS

ＡＮＥＷＡＮＡＬＹＴＩＣＡＬＭＥＴＨＯＤＦＯＲＯ２ＡＮＤＣＯ２ＴＲＡＮＳＦＥＲＩＮＳＨＥＬＬ－ＡＮＤ－ＴＵＢＥ（ＩＮＴＲＡ－ＬＵＭＩＮＡＬＦＬＯＷ）ＯＸＹＧＥＮＡＴＯＲＳＡＮＥＷＡＮＡＬＹＴＩＣＡＬＭＥＴＨＯＤＦＯＲＯ２ＡＮＤＣＯ２ＴＲＡＮＳＦＥＲＩ...     

EFFECT OF SUSPENDING MEDIUM VISCOSITY ONORIENTATION AND DEFORMATION OF RBCs IN A SHEAR FlOW FIELD

ＥＦＦＥＣＴＯＦＳＵＣＰＥＮＤＩＮＧＭＥＤＩＵＭＶＩＳＣＯＳＩＴＹＯＮＯＲＩＥＮＴＡＴＩＯＮＡＮＤＤＥＦＯＲＭＡＴＩＯＮＯＦＲＢＣＳＩＮＡＳＨＥＡＲＦｌＯＷＦＩＥＬＤＷｅｎＺｏｎｇ－ｙａｏ，ＭａＷｅｉｙｕａｎ，ＧａｏＴｉｅ，ＳｕｎＤａｇｏｎｇＤｅｐａ...     

ELECTRON MICROSCOPE ANALYSIS OF MITOCHONDRIA ON RENAL TUBULE CELL SUFFERED WARM ISCHEMIC AND REPER FUSIVE DAMAGE IN RABBITS

ＥＬＥＣＴＲＯＮＭＩＣＲＯＳＣＯＰＥＡＮＡＬＹＳＩＳＯＦＭＩＴＯＣＨＯＮＤＲＩＡＯＮＲＥＮＡＬＴＵＢＵＬＥＣＥＬＬＳＵＦＦＥＲＥＤＷＡＲＭＩＳＣＨＥＭＩＣＡＮＤＲＥＰＥＲＦＵＳＩＶＥＤＡＭＡＧＥＩＮＲＡＢＢＩＴＳＥＬＥＣＴＲＯＮＭＩＣＲＯＳＣＯＰＥＡ...     

DEVELOPED AND CLINICAL APPLICATION OF LOCK-RING TYPE BIPOLAR HIP PROSTHESIS

ＤＥＶＥＬＯＰＥＤＡＮＤＣＬＩＮＩＣＡＬＡＰＰＬＩＣＡＴＩＯＮＯＦＬＯＣＫ－ＲＩＮＧＴＹＰＥＢＩＰＯＬＡＲＨＩＰＰＲＯＳＴＨＥＳＩＳＤＥＶＥＬＯＰＥＤＡＮＤＣＬＩＮＩＣＡＬＡＰＰＬＩＣＡＴＩＯＮＯＦＬＯＣＫ－ＲＩＮＧＴＹＰＥＢＩＰＯＬＡＲＨＩＰＰＲＯ...     

THE WAVELET ANALYSIS OF EVOKED POTENTIALS

ＴＨＥＷＡＶＥＬＥＴＡＮＡＬＹＳＩＳＯＦＥＶＯＫＥＤＰＯＴＥＮＴＩＡＬＳＴＨＥＷＡＶＥＬＥＴＡＮＡＬＹＳＩＳＯＦＥＶＯＫＥＤＰＯＴＥＮＴＩＡＬＳＬｉＧｕａｎ；ＤａｚｏｎｇＪｉａｎｇ（ＢｉｏｍｅｄｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＲｅｓｅａｒｃｈｉｎｓｔｉ...     

TREATMENT OF FULMINANT LIVER FAILURE WISTAR RATS WITH IMPLANTED ARTIFICIAL CELLS MICROENCAPSULATED LIVING HEPATOCYTES

ＴＲＥＡＴＭＥＮＴＯＦＦＵＬＭＩＮＡＮＴＬＩＶＥＲＦＡＩＬＵＲＥＷＩＳＴＡＲＲＡＴＳＷＩＴＨＩＭＰＬＡＮＴＥＤＡＲＴＩＦＩＣＩＡＬＣＥＬＬＳＭＩＣＲＯＥＮＣＡＰＳＵＬＡＴＥＤＬＩＶＩＮＧＨＥＰＡＴＯＣＹＴＥＳＳｏｎｇＪｉｃｈａｎｇ，ＬｉＴａｏ，ＸｕＪ...     

STUDY OF NOVEL MEMBRANOUS MATERIAL FOR CHARCOAL KIDNEY

ＳＴＵＤＹＯＦＮＯＶＥＬＭＥＭＢＲＡＮＯＵＳＭＡＴＥＲＩＡＬＦＯＲＣＨＡＲＣＯＡＬＫＩＤＮＥＹＳＴＵＤＹＯＦＮＯＶＥＬＭＥＭＢＲＡＮＯＵＳＭＡＴＥＲＩＡＬＦＯＲＣＨＡＲＣＯＡＬＫＩＤＮＥＹＧｕＨａｎｑｉｎｇ；ＬｕＭｏｚｕ（Ｔｉａｎｊｉｎｉｎｓｔｉｔｕ...     

6MV-15MV下物理楔形因子和动态楔形因子的比较

目的:探讨不同能量下,Varian21EX直线加速器中物理楔形因子和动态楔形因子受照射野大小和深度的影响。方法:在固体水膜体中利用0.6 cc电离室对6 MV和15 MV射线束下不同角度物理楔形板和动态楔形板分别测量加和不加楔形滤片时的剂量率来计算楔形因子。通过测量不同角度的物理楔形板和动态楔形板在固定照射野(10 cm×10 cm)的不同深度下的楔形因子来研究楔形因子随深度的变化规律。同时,对于楔形因子随射野大小的变化规律,还测量了不同角度的物理楔形板和动态楔形板在固定深度(d=10 cm)下的不同射野大小的楔形因子。为了更好地分析物理楔形因子与动态楔形因子的差异,引入了相对楔形因子NWF。结果:深度对于物理楔形板的楔形因子较为明显,深度增加时楔形因子增大,且随着楔形角的增大变化更明显。对于150、300、450、600的物理楔形板,当深度由最大深度增加到20 cm时对于6 MV能量楔形因子分别增加了1.86%、3.79%、4.99%、7.95%;对于15 MV能量1.29%、1.35%、1.49%、2.03%。而动态楔形因子随深度变化不明显,最大变化不到1%。射野大小对于物理楔形因子也有一定的影响,楔形因子随射野增加而增加,但是增加幅度不大;而对于动态楔形板,在6 MV和15 MV射线束下楔形因子受射野的增大都有明显的减小。对于100、150、200、250、300、450、600的动态楔形板,从参考射野(10 cm×10 cm)到最大射野,楔形因子分别减少了7.91%、11.04%、14.08%、16.96%、19.7%、28.03%、35.89%对于6 MV和5.72%、8.17%、10.41%、12.85%、15.08%、21.82%、30.59%对于15 MV能量。结论:对于物理楔形板,深度和射野大小都对物理楔形因子有影响,所以临床剂量计算时必须考虑深度和射野大小对物理楔形因子的影响并对它进行修正。对于动态楔形板,深度对动态楔形因子影响较小,在临床剂量计算时可以忽略;而射野大小对动态楔形因子影响比较明显,在临床剂量计算时只须考虑相对射野楔形因子。     

Field size dependence of wedge factors

The radiation output in the presence of wedge filters is characterized by the wedge transmission factor and open beam field size factors. Conventionally, the wedge factor for high-energy photons is measured in a water phantom at depth of maximum dose for a reference field size. Experimental measurements on different wedges indicate that the wedge factors are a function of field size. An analysis of these data show that this is primarily caused by the change in scattered radiation from the treatment head in the presence of wedge filters. The change in phantom scatter and radiation backscattered to the monitor chamber are minimal. For 4- or 6-MV x rays with a 60 degrees wedge, the use of a single wedge factor measured for 10 cm X 10 cm field introduces errors of up to 3.5%, for a 16-cm-wide field. For a 20-cm-wide field with this wedge, the error is 7%. Thinner wedges exhibit less differences.     

Wedge factor dependence with depth and field size for fast neutron beams

The dependence of the wedge factors (WFs) on field size (FS) and depth for a fast neutron beam has been investigated. In a previous study (Popescu et al 1999 Med. Phys. 26 541), a method was presented that allows a simple and accurate way of calculating the wedge-factor dependence on FS and depth in the case of a photon beam. The validity of a similar approach is tested in the present study for neutron beam dosimetry. The clinical neutron therapy system at the University of Washington (UW) has a flattening filter assembly consisting of two filters: a small field filter and a large field filter. Despite this complication, the approach presented in Popescu et al (1999 Med. Phys. 26 541) can be used to describe the WF dependence on FS and depth (d).     

Wedge factor dependence on depth and field size for various beam energies using symmetric and half-collimated asymmetric jaw settings.

The depth- and field-size dependence of the in-phantom wedge factor have been determined for a Cobalt-60 (Co-60) teletherapy unit and four medical linear accelerators with 4-, 6-, 10-, and 18-MV x-ray beams containing 15 degrees-60 degrees (nominal) lead, brass, and steel wedge filters. Measurements were made with ionization chambers in solid water or water with a source-skin distance of 80 or 100 cm. Field sizes varied from 4 x 4 cm up to a maximum allowable size for each wedge filter. Measurements were performed for symmetric and half-collimated asymmetric fields at depth of maximum dose, 5- and 10-cm depths. For half-collimated fields, wedge factor reference points were located at a fixed off-axis distance from the collimator's rotational axis. These systematic measurements on wedges indicate that the wedge factor dependence on depth and field size is a function of beam energy as well as the design of the treatment head and wedge filters. Significance of the results reported herein are discussed for the most commonly used treatment depths and field sizes with various beam energies and wedge filters.     

楔形野剂量计算中的误差分析和修正

目的研究楔形野剂量计算中的误差,并探讨解决方法.材料与方法在10MV和6MVX线条件下,用NEFarmer25710.6cc指形电离室和三维水箱在水模中测出平野和楔形野的各种参数,并用二种方法计算剂量,结果与实侧值比较.结果实测数据显示Pdd和Scp在平野和楔形野情况下存在差异.楔形因子因此随深度而变化,变化程度受射线能量、楔形板规格影响.与实测值比较,用传统方法计算楔形野剂量的结果存在误差,误差大小与能量、野面积、深度有关.6MVX线、15×15野、20cm深度处的计算误差可达11%.而用改进的方法进行计算,可将误差控制在1%以内.结论由于忽略了Pdd等物理参数在楔形野条件下的变化,用传统方法计算楔形野剂量存在误差.为保证临床剂量计算的准确性,应在计算公式中加入修正因子.     

Beam characteristics of upper and lower physical wedge systems of Varian accelerators

The beam characteristics of a dual physical wedge system, upper and lower, for Varian accelerators are studied over the energy range 6-18 MV. Wedge factors for both systems are measured in a water phantom as a function of field size, depth and source-to-wedge (SWD) distance. Our results indicate that apart from their physical differences, dosimetrically, the two wedge systems have <2% difference in central axis percentage depth dose beyond the build-up region. The lower wedge central axis percentage depth dose is consistently lower than that of the corresponding upper wedge, with the effect more pronounced for large field sizes. The wedge profiles are identical within 2% for all field sizes, depths and energies. The wedge factors for both wedge systems are also within 2% for all field sizes and depths for both 6 and 15 MV photons and slightly higher for the 18 MV beam and 45 degrees-60 degrees wedge angle. The wedge factor variation with SWD reveals an interesting fact that thinner wedges (15 degrees and 30 degrees) result in a higher surface dose in the central axis region than thicker wedges. As the SWD increases beyond 80 cm, the reverse is true, i.e. thicker wedges produce higher surface dose than thinner wedges. It is also verified that the wedge factor at any depth and for any field size can be calculated from the wedged and open field central axis percentage depth dose, and the wedge factor at dmax, resulting in nearly 44% reduction in water phantom scanning and 80% reduction in point measurements during commissioning.     

Elekta Motorized Wedge 6MV X-ray楔形因子特性的初步研究

目的：探讨Elekta motorized wedge楔形因子随射野宽度和测量深度的变化特性。方法：对Elekta Precise直线加速器6 MV X-ray,用Farmer 2571指形电离室和美国Capintec 192剂量仪,在固定测量深度的条件下,逐步扩大射野,实测获得15°,30°,45°,60°四个角度楔形板的楔形因子随射野宽度的变化特性;在固定射野宽度的条件下,逐步改变测量点的深度,实测获得15°,30°,45°,60°四个角度楔形板的楔形因子随测量深度的变化特性;同时,将每个实测到得的楔形因子与Elekta Precise TPS 2.12模拟实测条件输出的楔形因子进行了对比。结果：Elekta motorized wedge楔形因子随射野宽度和测量深度的增加而变大,呈现线性变化。当FSZ〈20 cm×20 cm时,楔形因子随射野宽度线性变化的斜率比较大,当FSZ〉20 cm×20 cm时,楔形因子随射野宽度线性变化的斜率比较小,深度对楔形因子的影响小于射野宽度。Elekta Pre-cise TPS 2.12模拟实测条件输出的楔形因子与实测得到的相近,偏差较小。结论：当FSZ〈20 cm×20 cm时,宽度对楔形因子的影响不能忽略,因此处方剂量计算时应先求得等效方野,而后用该等效方野对应的楔形因子进行楔形野的处方剂量计算;当FSZ〉20 cm×20 cm时,可以采用20 cm×20 cm测得的楔形因子进行楔形野的处方剂量计算;深度对楔形因子的影响可忽略,可以将参考深度（水下10 cm）获得的楔形因子用于所有的深度。     

Elimination of field size dependence of enhanced dynamic wedge factors

Enhanced dynamic wedge factors (EDWF) are characterized by a strong field size dependence. In contrast to physical wedge factors, the EDWF decrease as the field size is increased: for 6 MV 60 degrees wedge, the EDWF decreases by 50% when the field size is increased from 4 x 4 cm2 to 20 x 20 cm2. A method that eliminates the field size dependence of EDWF was developed and investigated in this work. In this method, the wedged field shape is determined by a multileaf collimator. The initial position of the moving Y jaw is determined by the field size and the stationary Y jaw is kept fixed at 10 cm for field sizes < or = 20 cm in the wedged direction. For all other fields, the stationary Y jaw setting is determined by the field size. The modified method results in EDWF that are independent of field size, with no change in the wedge dose distribution when compared with the conventional use of EDW.     

Dosimetry characteristics of large wedges for 4- and 6-MV x rays

Two sets of newly designed large wedge filters for field sizes up to 20 X 20 cm2 have become commercially available for use with 4- and 6-MV linear accelerators. Such field sizes are sometimes required to ensure adequate coverage in certain treatment techniques. This work reports base line data resulting from an investigation of the dosimetric properties of these wedges. Measurements of wedge angles, transmission factors, and beam hardening effects are described, and comparisons are made with the smaller standard wedges.     

Wedge factor dependence with depth, field size, and nominal distance--a general computational rule

We have investigated the dependence of the wedge factors with field size, depth, nominal, and extended distances for 4, 6, 18, and 24 MV photon beams. Analysis of the experimental data suggests a general linear dependence of the wedge factors with field size and depth. The study shows that changes in wedge factors are insignificant (< or = +/-1.0%) with respect to measurements at nominal SSD, SAD, or extended SSD. This independence of the wedge factors on source-to-surface distance was studied for different photon energies (4-24 MV) and for different attenuating wedges (external and internal wedges). For clinical applications, an algorithm is presented to calculate the wedge factor dependence with field size and depth. The new algorithm has been successfully implemented to replace wedge look-up tables for dose and MU calculations in PRISM 1.2 treatment planning system used in our department.