The purpose of this study is to investigate the effects of tissue heterogeneity and breathing-induced motion/deformation on conformal treatment planning for pulmonary tumors and to compare the magnitude and the clinical importance of changes induced by these effects. Given a properly designed ITV, tissue heterogeneity effects are likely to have a larger clinical significance on tumor and normal lung treatment evaluation metrics than four-dimensional

In this study we investigated the accumulation of dose to a deforming anatomy (such as lung) based on voxel tracking and by using time weighting factors derived from a breathing probability distribution function.

In this study, we show that beam model differences play an important role in the comparison of dose calculated with various algorithms for lung cancer treatment planning. Although the extent to which beam model differences impact the dose comparisons will be dependent upon beam parameters (orientation, field size and energy), and the size and location of the tumour, this study shows that failing to correctly account for beam model differences will

We have applied convolution methods to account for some of the effects of respiratory induced motion in clinical treatment planning of the lung. The 3-D displacement of the GTV center-of-mass (COM) as determined from breath-hold exhale and inhale CT scans was used to approximate the breathing induced motion. The time-course of the GTV-COM was estimated using a probability distribution function (PDF) previously derived from diaphragmatic motion [Med.

We describe the implementation of a fluence convolution method to account for the influence of superior-inferior (SI) respiratory induced motion on a Monte Carlo-based dose calculation of a tumor located in the liver. This method involves convolving the static fluence map with a function describing the SI motion of the liver-the motion function has been previously derived from measurements of diaphragm movement observed under fluoroscopy. Significant

Setup variations and breathing induced movements create differences between calculated and delivered doses for intra-hepatic lesions. Changes in NTCP are clinically relevant and statistically significant. Although PTV concept ensure adequate CTV coverage, doses to normal liver are incorrectly modeled without including patient related geometric uncertainties.

A combined precision experimental and theoretical tsudy of 5p2Pj->5d2D3/2 electric-dipole transition matrix elements in atomic 87-Rb has shown that they are dominated by electron correlation. The relative size of the measured matrix elelment ratio is found to be 1.068(8), in very good agreement with the value of 1.135 obtained from relativistic third-order many-body perturbation theory