objective(s): in this study we evaluate the impact of the different aspects of gold nano-particles (gnps) on the target absorptive dose enhancement factor (def) during external targeted radiotherapy with photon beams ranging from kilovolt to megavolt energies using monte carlo simulation. methods: we have simulated the interaction of photon beams with various energies of radiation using water s...

Introduction: This study was designed to evaluate dosimetric parameters such as rectal dose, bladder dose, integral dose (ID), homogeneity index (HI) and conformity index (CI) in various treatment plans for prostate cancer. Materials and Methods: Pelvic computed tomography (CT) scans of 27 patients were acquired and transferred to the RTDosePLAN treatment planning system. For each patient, 8 co...

Introduction: In radiation therapy, knowing the dose rates to healthy organs and tumors is beneficial, and thermoluminescent dosimeter (TLD) allows for this possibility. This study was aimed at determining the dose-response differences of TLDs in various types of radiation, energy levels, and dose rate calibrated with other types of radiation beams and energy and dose levels. Materials and Meth...

monte carlo simulation is widely used in calculations involing transport of photons through different materials of different shapes. the method consists of randomly generating a finite set of photon histories over which the quantities of interest are averaged. in photon transport calculations, sampling the photon scattering angle from the klein-nishina probability distribution is of special imp...

radiotherapy dose calculations can be evaluated by monte carlo (mc) simulations with acceptable accuracy for dose prediction in complicated treatment plans. in this work, standard, livermore and penelope electromagnetic (em) physics packages of geant4 application for tomographic emission (gate) 6.1 were compared versus monte carlo n-particle extended (mcnpx) 2.6 in simulation of 6 mv photon lin...

introduction: this study was designed to evaluate dosimetric parameters such as rectal dose, bladder dose, integral dose (id), homogeneity index (hi) and conformity index (ci) in various treatment plans for prostate cancer. materials and methods: pelvic computed tomography (ct) scans of 27 patients were acquired and transferred to the rtdoseplan treatment planning system. for each patient, 8 co...

background: as bremsstrahlung photon beam fluence is important parameter to be known in a photonuclear reaction experiment as the number of produced particle is strongly depends on photon fluence. materials and methods: photon production yield from different thickness of aluminum target has been estimated using artificial neural network (ann) model. target thickness and incoming electron energy...

background: during radiotherapy treatment, critical organs are shielded using lead and cerrobend blocks. the objective of this study is to compare the effects of lead and cerrobend shielding blocks on incident photon beam. methods: collimator scatter factors were measured for open square fields (3 x 3 cm to 40 x 40 cm) defined by collimator jaws and for fields blocked down to smaller asymmetric...