A computer program for determination of X-ray spectra from attenuation data was written using the Gauss-Seidel method. In order to specify the required properties of the input data, simulations were carried out based on catalogue data of X-ray spectra published by HPA. The results showed that the following three items were important to give reliable solutions.
1) Attenuation data must be measured until the penetrated fraction reachs.5%. The accuracy of the attenuation_data must be within 0.5% error.
2) The energy width of the histogram must be less than lkeV.
3) An empirical functicn derived by the authors was recommended as the initial approximated solution to the Gauss-Seidel subroutine.
The simulations suggested that the program was able to give applicable spectral data.

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Some parameters are included in the formulae for effective mass stopping power ratio in high-energy photon and electron dosimetry. In photon beams, the correction factor for transmission, through the cavity wall to the cavity, of secondary electrons arising in medium and the build-up rate in the wall of secondary electrons arising in the wall are estimated on the basis of two very simple models, an exponential attenuation and build-up model and a parallel plate model. In electron beams, the correction factor for transmission, through the wall to the cavity, of electrons is estimated from transmission probability of electrons. As an example, the values of those parameters are calculated for the JAM. substandard air ionisation chamber in water phantom. Although it seems to be open problem whether these models approximate correctly some complicated situations in practical dosimetry, the parameter values obtained in present work may be temporarily used till a better model would be known.

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analysis, Uterus, Ovarium A temperature dependence o f the Ti at 15.0 MHzo f 1H-NMRw as observed for three surgical specimens obtained from the uterus and the ovarian tumor of a patient. The T1 value of the ovarian tumor was forty percent longer than T1values of other specimens. Activation energies for motions of water in each specimen were obtained as 9.1±0.7 kJmo1-1 for the myometrium of the uterus,9.5±1.0 kJmo1-1 for the myomnode of the uterus and 13.6±0.9 kJmo1-1 for the ovarian tumor. Differential thermal analyses showed evident difference between the ovarian tumor and the others, but did not show such a difference between the myometrium and the myomnode.

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