Hierarchical Penumbra Casting

Investigation of physical penumbra definition in treatment planning

Background: Due to the small size of the beamlets in IMRT (intensity modulated radiotherapy), physical penumbra is one of the important dosimetric parameters and small changes in the penumbra have a notable impact on the results. The physical penumbra width is defined as the lateral distance between two specified isodose curves at a specified depth of phantom. In this study, after demonstrating...

Investigation of physical penumbra definition in IMRT applications

Introduction: Because of small size of the beamlets in IMRT, physical penumbra is one of the important dosimetric parameters and small changes in the penumbra will have a great impact on the results. The physical penumbra width is defined as the lateral distance between two specified isodose curves at a specified depth of phantom. In this study, after demonstrating the inconsi...

Structure of proper motions in a sunspot penumbra

A Survey of Real-time Soft Shadows Algorithms

Recent advances in GPU technology have produced a shift in focus for real-time rendering applications, whereby improvements in image quality are sought in addition to raw polygon display performance. Rendering effects such as antialiasing, motion blur and shadow casting are becoming commonplace and will likely be considered indispensable in the near future. The last complete and famous survey o...

A Half-Skewed Octree for Volume Ray Casting

A hierarchical representation formed by an octree for a volume ray casting is a well-known data structure to skip over transparent regions requiring little preprocessing and storage. However, it accompanies unnecessary comparison and level shift between octants. We propose a new data structure named half-skewed octree, which is an auxiliary octree to support the conventional octree. In preproce...