AIM The aim of the study was to estimate the dose at the reference point applying an aSi-EPID device in the course of patient treatment. MATERIALS AND METHODS The method assumes direct proportionality between EPID signal and dose delivered to the patient reference point during the treatment session. The procedure consists of treatment plan calculation for the actual patient in the arc techniq...

Intensity-modulated radiation therapy (IMRT) provides the protection of the normal organs and a precise treatment plan through its optimization process. However, the final dose-volume histogram (DVH) obtained by this technique differs from the optimal DVH, owing to optimization convergence errors. Herein, intermediate dose calculation was applied to IMRT plans during the optimization process to...

The 6 MV flattening filter-free (FFF) beam has been commissioned for use with compensators at our institution. This novel combination promises advantages in mitigating tumor motion due to the reduced treatment time made possible by the greatly increased dose rate of the FFF beam. Given the different energy spectrum of the FFF beam and the beam hardening effect of the compensator, the accuracy o...

The aim of this study was to demonstrate how dosimetry with an amorphous silicon electronic portal imaging device (a-Si EPID) replaced film and ionization chamber measurements for routine pre-treatment dosimetry in our clinic. Furthermore, we described how EPID dosimetry was used to solve a clinical problem. IMRT prostate plans were delivered to a homogeneous slab phantom. EPID transit images w...

Introduction Use of nonselective refocusing pulses shortens the echo spacing and the echo train duration, and then improves the image sharpness in SPACE [3, 4] imaging. However, the nonselective refocusing pulses limit the application of slab selective acquisition. To overcome this limitation, a dual echo-spacing technique [1] has been presented before, using a combination of selective excitati...

The heterogeneous nucleation of liquid droplet on a solid surface was simulated with the molecular dynamics method. Argon vapor was represented by 5760 Lennard-Jones molecules and the solid surface was represented by one layer of 1020 harmonic molecules with the constant temperature heat bath model using the phantom molecules. The potential parameter between solid molecule and vapor molecule wa...

Heterogeneous nucleation of a liquid droplet on a solid surface was simulated with the molecular dynamics method. Argon vapor was represented by 5,760 Lennard-Jones molecules and the solid surface was represented by one layer of 4,464 harmonic molecules with the constant temperature heat bath model using the phantom molecules. The potential parameter between a solid molecule and a vapor molecul...

background: in treating patients with radiation, the degree of accuracy for the delivery of tumor dose is recommended to be within ± 5% by icru in report 24. the experimental studies have shown that the presence of low-density inhomogeneity in areas such as the lung can lead to a greater than 30% change in the water dose data. therefore, inhomogeneity corrections should be used in treatment pla...