We have designed a toolbox that provides an environment for testing radiotherapy optimization techniques, objective functions, and constraints. A set of three-dimensional (3D) pencil beam dose distributions have been computed for a cylindrical phantom. The 6 MV pencil beams were computed using a superposition-based dose engine commissioned for an Elekta SL20 linear accelerator. Due to the cylin...

A model for beam customization with collimators and a range-compensating filter based on the phase-space theory for beam transport is presented for dose distribution calculation in the treatment planning of radiotherapy with protons and heavier ions. Independent handling of pencil beams in conventional pencil-beam algorithms causes unphysical collimator-height dependence in the middle of large ...

Type Ia supernovae (SNe Ia) can be calibrated to be good standard candles at cosmological distances. However, at z > ∼ 1, gravitational lensing leads to significant level of noise in a SN Hubble diagram. We propose a pencil beam survey of SNe Ia which would yield a significant number of SNe in redshift bins of 0.1 for z up to 2. The SN number count can provide a direct probe of cosmology which ...

To continue and expand upon the foundation provided by the recent flight of the NASA Scatterometer (NSCAT), NASA is developing the SeaWinds instrument which is scheduled to fly on the Quikscat mission in November 1998, and on the Second Japanese Earth Observation Satellite (ADEOS-11) to be launched in early 2000. In a significant design departure from previous “fan-beam” scatterometer systems, ...

Convolution/superposition software has been used to produce a library of photon pencil beam dose matrices. This library of pencil beams is designed to serve as a tool for both education and investigation in the field of radiotherapy optimization. The elegance of this pencil beam model stems from its cylindrical symmetry. Because of the symmetry, the dose distribution for a pencil beam from any ...

PURPOSE To verify the clinical pencil beam dose calculation algorithm for passive scattering proton therapy using field with large range in tissue, i.e. in prostate cancer, using a Monte Carlo (MC) simulation system. METHODS Previously treated prostate cancer cases were randomly selected from our patient database. All patients received the same dose prescription of 50Gy (25 fractions) to plan...

This study quantifies the dosimetric accuracy of a commercial treatment planning system as functions of treatment depth, air gap, and range shifter thickness for superficial pencil beam scanning proton therapy treatments. The RayStation 6 pencil beam and Monte Carlo dose engines were each used to calculate the dose distributions for a single treatment plan with varying range shifter air gaps. C...

Particles are used in medical application for cancer treatment. Radiotherapy aims to deliver a high dose in a well-defined target volume while sparing the healthy surrounding tissues. Compared to the conventional radiotherapy (X-ray), protons show superior clinical performances thanks to their inherent depth dose characteristic (Bragg peak). In proton therapy, several techniques can be used to ...