BACKGROUND Photon beam is most widely being used for radiation therapy. Biological effect of radiation is concerned with the evaluation of energy absorbed in the tissues. It was aimed to analyse the depth dose characteristics of x-ray beams of diverse energies to enhance the quality of radiotherapy treatment planning. METHODS Depth dose characteristics of different energy photon beams in wate...

Introduction:  Skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. However, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. This phenomenon tends to increase the skin dose received b...

Background: One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment.Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Methods: Simulations were performed using MCNPX Monte...

A three dimensional treatment planning system has been installed in the Oncology Center, Bangladesh. This system is based on the Anisotropic Analytical Algorithm (AAA). The aim of this study is to verify the validity of photon dose distribution which is calculated by this treatment planning system by comparing it with measured photon beam data in real water phantom. To do this verification, a q...

PURPOSE Thermoluminescent dosimeters are used routinely for dosimetric measurements of photon and electron fields. However, no work has been published characterizing TLDs for use in combined photon and electron fields. This work investigates the response of TLD-100 (LiF:Mg,Ti) in mixed fields of photon and electron beam qualities. METHODS TLDs were irradiated in a 6 MV photon beam, 6 MeV elec...

After discussing various examples, the diameter of a single photon is calculated by combining the formulas of quantum mechanics and wave theory. The experimentally known coherence length is the length of the photon.

The nonlocal emitter-waveguide coupling, which gives birth to the so called giant atom, represents a new paradigm in field of quantum optics and waveguide QED. We investigate single-photon scattering one-dimensional on two-level or three-level atom. Thanks natural interference induced by back forth photon transmitted/reflected between atom-waveguide coupling points, transmission can be dynamica...

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 wi...