摘要:

A method for absolute calibration of diagnostic x‐ray generators is presented and discussed. The method employs a Ge(Li) detector and relies on the direct observation of the onset of fluorescence radiation from scattering foils placed in the primary beam.

ISSN:0269-3127    

DOI:10.1118/1.594155

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

Interchange or transfer of radiographic techniques through measurement of penetration quality is discussed. The usefulness of this achievement is verified using an aluminum step wedge. Also, the procedure described provides a method for performance evaluation of kVp compensation on diagnostic x‐ray installations.

ISSN:0269-3127    

DOI:10.1118/1.594156

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

We propose the use of high energy electrons in a strong local magnetic field as the ionizing beam in radiation therapy. A high kinetic energy insures that the electrons will penetrate to deep‐seated tumor masses. A high magnetic field of several tesla in the region encompassing the tumor will confine the high energy electrons to the tumor volume before the scattering of the beam becomes excessive, thus producing an enhanced electron “Bragg peak” and highly localized strong radiation dose. The conclusions are based on a detailed Monte Carlo model which includes Landau straggling, multiple scattering, and the space dependence of the magnetic field.

ISSN:0269-3127    

DOI:10.1118/1.594157

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

Measurements of surface dose and build‐up have been measured for photon radiation sources with maximum energy from 1.2 to 25 MeV. A variable volume ionization chamber was used and the results extrapolated to what would be obtained with a zero volume chamber. The results are found to depend systematically on the plate separation of a parallel plate ionization chamber and an empirical method was derived for correcting measurements made with a fixed volume chamber. The relationship of dose build‐up curves with skin reactions in radiation therapy patients is discussed.

ISSN:0269-3127    

DOI:10.1118/1.594158

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

A technique utilizing x‐ray fluorescence has been used to measure remotely the volume and, thereby, the hydrostatic pressure of a cesium nitrate solutionin vitro. The excitation radiation source was99mTc, and the x‐ray spectra were measured with a sodium iodide spectrometry system. This technique may be applicable to long termin vivomeasurements of intracranial pressure for conditions such as hydrocephalus.

ISSN:0269-3127    

DOI:10.1118/1.594159

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

Much renewed interest has developed in electrostatic imaging systems. This is partly because of their use of relatively inexpensive materials and their potential for improved diagnostic accuracy—a novel combination of image latitude with great detail contrast. All such systems can exhibit these image characteristics when developed by the generally used “powder cloud” technique or some similar partial development system. We have measured edge sharpness and enhancement of electron radiographs (ERGs) produced with the powder cloud technique. Edge sharpness can be excellent at low image‐density levels, but deteriorates with increasing density. Edge enhancement is also appreciable; it appears to decrease somewhat with increasing image density, but no simple relationship has yet been shown.

ISSN:0269-3127    

DOI:10.1118/1.594160

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

The conceptual and mathematical description of a method to draw a three‐dimensional histographic surface in oblique projection, with the drawing of hidden parts suppressed, is given.

ISSN:0269-3127    

DOI:10.1118/1.594161

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

A graphics‐tablet treatment planning system is described. The cost effectiveness of this approach is especially attractive where time‐sharing use of a central computer facility is available.

ISSN:0269-3127    

DOI:10.1118/1.594162

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

摘要:

Establishing a computerized tumor registry involves careful consideration of a number of factors. Included in this consideration are the cost of both software and hardware, the type and selection of data needed, and the ongoing cost of the program. A representative listing of the data to be collected for the radiotherapy tumor registry is included.

ISSN:0269-3127    

DOI:10.1118/1.594163

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY

ISSN:0269-3127    

DOI:10.1118/1.594164

出版商:American Association of Physicists in Medicine    

年代:1998

数据来源: WILEY