Introduction Accurate dose delivery is critical to the success of stereotactic radiosurgery. Unfortunately, verification of the accuracy of treatment delivery remains a challenging problem. Existing radiosurgery delivery paradigms are limited in their ability to verify the accurate delivery of radiation beams using data sampled from the beam after it has traversed the patient. The Zap-X Radiosu...

The x-ray attenuation values of brain studied with computed tomography (CT) are strikingly affected by the ages of the subjects. Premature neonates, for example, may have brain attenuation values 20-30 H below adult values. These lower attenuation values for developing compared with adult brain can be ascribed partly to machine-related effects (beam-hardening, adult algorithms, scanning geometr...

The frequency statistics of the backscattered waveform observed between tissue boundaries can be matched to a model to estimate the characteristic size of the scatterer in the tissue region of interest. In the past, the models have all assumed plane wave propagation requiring the use of unfocused or weakly focused sources in the experiment. In our work, we challenged this assumption by re-deriv...

We present an attenuation-corrected "nondiffracting" Airy beam. The correction factor can be adjusted to deliver a beam that exhibits an adjustable exponential intensity increase or decrease over a finite distance. A digital micromirror device that shapes both amplitude and phase is used to experimentally verify the propagation of these beams through air and partially absorbing media.

High-attenuation object-induced streaking and shadow artifacts in computerized tomography (CT) are somewhat connected to the misfit of the X-ray projection data to the range space of the Radon transform. This misfit is mainly due to the beam hardening factor of the projection data which is unavoidable for polychromatic sources. The major difficulty in dealing with the beam hardening-induced str...

The spatial scrambling of upper-Stark-state (KM J,0)-selected beams of CH3F, CH3Cl, CH3Br, and CH3I in field-free space has been investigated. It has been proposed that the mechanism for spatial deorientation as the electric-field strength is reduced to zero is the change in precessional frequency and loss of spatial direction as the total angular momentum J decouples from the collapsing electr...

In intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT), the use of posterior oblique beams has become common. Beam attenuation by the treatment couch is not negligible when the couch is in the beam portal. In this study, we established the relationship of relative dose vs. beam angle for two Varian 21EX linacs, one equipped with the Exact couch (standard cou...

Multimode quantum correlations and entanglements has drawn much attention recently due to its importance for both fundamental science the future development of information processing communication. Here, by using a four-wave mixing process with conical pump beam probe beam, we experimentally generate multimode between conjugate also observe about –2.6-dB intensity-difference squeezing these two...

Computed tomography (CT) devices are routinely employed to obtain three-dimensional images of the human body. The reconstructed CT numbers represent weighted x-ray attenuation coefficients. Their spectral weighting is influenced by the selected x-ray source spectrum, the detector characteristics, and the attenuating object itself. The quantitative ground truth of the scanned object is given by ...

Introduction: The heavyweight concretes have been widely used for constructing medical or industrial radiation facilities with photon sources. Materials and Methods: In this study, heavy concretes containing galena (PbS) and several borated minerals are proposed as suitable materials against photons. The shielding properties of 21 galena concretes containing seven borated minerals with three m...