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Neutron production in radiotherapy facilities has been studied from the early days of modern linacs. Detailed studies are now possible using photoneutron capabilities of general-purpose Monte Carlo codes at energies of interest in medical physics. The present work studies the effects of modelling different accelerator head and room geometries on the neutron(More)
In the present study, the authors explored the effect of manipulating the distance between footfalls (pace length) in level walking in 3 men. The translational kinetic energy to gravitational potential energy (E(k)-E(p)) exchange was found to be maintained until pace length reached approximately 110% of single limb length. Beyond that pace length, the(More)
5,5-Dimethyl-1,3-cyclohexanedione (dimedone) reacts in acid aqueous solution with selenium(IV) to give a benzoxaselenol which has an absorption maximum at 313 nm with a molar absorptivity of 4.00 x 10(3) l.mole(-1).cm(-1). The compound is extractable into chloroform, to give a solution with an absorption maximum at 300 nm with a molar absorptivity of 3.77 x(More)
We have constructed and tested a 2d position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This(More)
Free ion yield observed in liquid isooctane irradiated by γ rays. Comparison with the Onsager theory Abstract We have analyzed data on the free ion yield observed in liquid isooctane irradiated by 60 Co γ rays within the framework of the Onsager theory about initial recombination. Several distribution functions describing the electron thermalization(More)
A method for commissioning an EGSnrc Monte Carlo simulation of medical linac photon beams through wide-field lateral profiles at moderate depth in a water phantom is presented. Although depth-dose profiles are commonly used for nominal energy determination, our study shows that they are quite insensitive to energy changes below 0.3 MeV (0.6 MeV) for a 6 MV(More)
We present a method based in the study of the edge spread function (ESF) obtained by using a solid metallic block image to measure the resolution of a radiotherapy EPID. With this simple method it is possible to determine the effective focal spot size of a LINAC, the intrinsic unsharpness of the portal imaging device and also its MTF response, which it is(More)
We have constructed and tested a 2d position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This(More)