Response of a micro volume (0.01 ml) ionization chamber has been studied with pulsed proton beams which are used for clinical purposes and has been compared with those of some JARP ionization chambers (0.6 ml). All chambers used had been calibrated by standard 60Co beams at the Electrotechnical Laboratory (ETL) and exposure calibration factors, Nx, were obtained on advance. Two methods are used...

INTRODUCTION Brachytherapy is an integral part in the treatment of cervical uteri cancer patients. Orthogonal treatment planning is the standard mode of calculation based on reference points. Introduction of the innovative 3-D computer based treatment planning allows accurate calculation based on volumetric information as regards the target volume and organs at risk (OAR). Also provide dose vol...

BACKGROUND AND PURPOSE Conformal radiotherapy requires accurate dose calculation at the dose specification point, at other points in the planning target volume (PTV) and in organs at risk. To assess the limitations of treatment planning of lung tumours, errors in dose values, calculated by some simple tissue inhomogeneity correction algorithms available in a number of currently applied treatmen...

The physical basis for the measurement of Hp(10) and H*(10) in mixed high-energy electron and photon fields was developed for the general case of non-existing secondary charged particle equilibrium at the reference depth of 10 mm. Several mixed fields, with different electron fluence distributions were produced and the corresponding depth ionisation curves were measured in a Makrolon phantom. B...

Fast neutrons and protons undergo fundamentally different interactions in tissue. The former interact with nuclei, while the latter, as in the case of photons, interact mainly with atomic electrons. Protons do, however, also undergo some nuclear interactions, the probability of which increases with energy. For both modalities the practical instruments for determining the reference absorbed dose...

The purpose of this study was to ensure accuracy in radiation dose delivery, external dosimetry quality audit has an equal importance with routine dosimetry performed at clinics. To do so, dosimetry quality audit was organized by the Secondary Standard Dosimetry Laboratory (SSDL) of Pakistan Institute of Nuclear Science and Technology (PINSTECH) at the national level to investigate and minimize...