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The estimation of the absorbed dose to the breast is an important part of the quality control of the mammographic examination. Knowledge of breast dose is essential for the design and performance assessment of mammographic imaging systems. This review gives a historical introduction to the measurement of breast dose. The mean glandular dose (MGD) is introduced as an appropriate measure of breast dose. MGD can be estimated from measurements of the incident air kerma at the surface of the breast and the application of an appropriate conversion factor. Methods of calculating and measuring this conversion factor are described and the results discussed. The incident air kerma itself may be measured for patients or for a test phantom simulating the breast. In each case the dose may be determined using TLD measurements, or known exposure parameters and measurements of tube output. The methodology appropriate to each case is considered and the results from sample surveys of breast dose are presented. Finally the various national protocols for breast dosimetry are compared.

It has been shown that good quality radiographic images can be formed by allowing the X-ray beam transmitted through an object to fall on an ionization chamber in which a layer of gas or liquid is confined between conducting surfaces. The ions formed by X-ray absorption in this layer are collected on an insulating foil lying over one of the electrodes, and the resulting charge distribution on the foil can then be developed by one of the toner techniques common in Xerography.There are many parameters which can be varied both in the design of the ionography chamber and in the development process. This paper considers the choice of these various parameters with a view to optimizing sensitivity and resolution and discusses in detail the efficiencies of different ionographic absorbers relative to selenium, the absorber used in Xeroradiography.

The experimental forward pion nucleon scattering amplitude is investigated in the light of the Harari model. We find that the two are incompatible. However, over the first three resonance regions at least, we find that the resonances alone give a good approximation to the full amplitude.

Differential cross sections for π+p and π−p elastic scattering have been measured with an accuracy of typically ±2% at 10 and 9 energies respectively in the range 88 to 292 MeV of lab kinetic energy.

Measurements have been made of the π ∓ proton total cross sections over the laboratory kinetic energy range 70 to 290 MeV. The absolute accuracy of the data is generally 0.5 %, but decreases to 1 % for some points where applied corrections are large or where low particle fluxes limit the statistical accuracy. The parameters of the Δ 0 , Δ ++ resonance have been calculated, and a discussion is included on the limitations placed by Coulomb barrier effects on extracting the basic nuclear phase shifts from data in this energy region.

Measurements have been made of the total charge-exchange cross section π − p to π 0 n over the laboratory kinetic energy range 90 to 290 MeV. The data have an absolute accuracy of typically 1%, and have here been used to determine the pion-nucleon P 13 phase shift.