OBJECTIVEDiscussing the basic application of scripting in RayStation TPS system.

METHODSOn the RayStation 3.0 Platform, the programming methods and the points should be considered during basic scripting application were explored with the help of utility scripts. The typical planning problems in the field of beam arrangement and plan outputting were used as examples by ironprthon language.

RESULTSThe necessary properties and the functions of patient object for script writing can be extracted from RayStation system. With the help of NET controls, planning functions such as the interactive parameter input, treatment planning control and the extract of the plan have been realized by scripts.

CONCLUSIONWith the help of demo scripts, scripts can be developed in RayStation, as well as the system performance can be upgraded.

This paper reviewed the dose calculation method for treatment planning system of multi-source stereotactic radiotherapy system with Gamma beam, and presented a fast method based on cone coordinate system and multi-core parallelization. The experiments show that the new method not only ensures the accuracy of dose calculation, but also greatly improves the speed, which can reach as 20 times as that of traditional method.
Algorithms ; Gamma Rays ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods

This article presents and discusses some special problems about the use of wedge field in radiation therapy according to the practice of the author. Thus we attain the rules of quality assurance in radiotherapy by WHO.
Quality Control ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods

OBJECTIVETo increase the accuracy of beam targeting and improve the dose distributions in radiotherapy using a robust image registration algorithm based on control volumes.

METHODSControl volume mapping and thin-plate spline deformable transformation were combined. The use of the control volumes increased the accuracy for the deformable registration. A bi-directional mapping method was also employed to correctly match the control volumes.

RESULTSThe clinical images were simulated using the proposed two-step image registration algorithm. The simulation results indicated that the registration algorithm was robust and universal, even in cases of obvious deformation.

CONCLUSIONSThe algorithm provides a more convenient and robust resolution as compared to manual landmark-based methods and single-step deformable transformations, and may help in automatic image registration in radiation therapy.

Dose calculation plays a key role in treatment planning of radiotherapy. Algorithms for dose calculation require high accuracy and computational efficiency. Finite size pencil beam (FSPB) algorithm is a method commonly adopted in the treatment planning system for radiotherapy. However, improvement on its computational efficiency is still desirable for such purpose as real time treatment planning. In this paper, we present an implementation of the FSPB, by which the most time-consuming parts in the algorithm are parallelized and ported on graphic processing unit (GPU). Compared with the FSPB completely running on central processing unit (CPU), the GPU-implemented FSPB can speed up the dose calculation for 25-35 times on a low price GPU (Geforce GT320) and for 55-100 times on a Tesla C1060, indicating that the GPU-implemented FSPB can provide fast enough dose calculations for real-time treatment planning.
Algorithms ; Computer Graphics ; Humans ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy, Conformal ; methods

In this paper, two new concepts of DR (Dose Repulsion) and DG (Dose Gravitation) are presented with their calculation formulas. For the problem of selecting beam arcs in x-knife radiotherapy Planning system, a mathematics model of constrained optimization has been built. Furthermore, we have produced a feasible project of automatic selecting optimized beam arcs plan using SA (Simulated Annealing) arithmetic based on the distribution of the fields of DR and DG in the reduced phase space.
Algorithms ; Brain Neoplasms ; radiotherapy ; Models, Theoretical ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy, Conformal ; methods

OBJECTIVETo implement dose reconstruction and dose-guided intensity modulated radiotherapy for helical tomotherapy.

METHODSDose reconstruction was implemented on adaptive helical tomotherapy with the online megavoltage CT (MVCT) imaging from a patient with nasopharyngeal cancer. The differences of isodose line between actual and planned deposition were analysis in 3D distribution, on which the hot spot and cold spot were lined. The dose delivered to these areas was modulated in later fractions to keep the planned requirement.

RESULTSThe differences between actual and planned isodose line were shown on the image visually. The modulation to the hot spot and cold spot in later fraction corrected the incorrectly delivered dose to achieve the requirement of primary plan.

CONCLUSIONSThe dose reconstruction and dose-guided intensity modulated radiotherapy can be implemented in adaptive helical tomotherapy.

Conformal radiation therapy using multi-leaf collimator (MLC) is considered as a conventional technology in the hospital nowadays. However the stepped leaf edge caused by the finite width of the leaves could influence the conformality that could be achievable. In this paper, the effect produced by rotating the collimator angle on the conformality was investigated. A method, in which multiple MLC fields of various rotation angles are applied, has been proposed to have the targets be more uniformly irradiated and thus to eliminate the cold spots on the targets and hot spots in normal tissues. By simulation, it has been shown that the multiple MLC field method can eliminate the stepped leaf edges and improve the conformality significantly, moreover, the PTV can receive a more uniform delivery with cold spot eliminated.
Humans ; Radiometry ; methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; instrumentation ; methods ; Radiotherapy, Conformal ; methods

The purpose of this study is to establish and apply a correction method for titanium alloy implant in spinal IMRT plan, a corrected CT-density table was revised from normal CT-density table to include the density of titanium alloy implant. Dose distribution after and before correction were calculated and compared to evaluate the dose deviation. Plans were also copied to a spinal cancer simulation phantom. A titanium alloy fixation system for spine was implanted in this phantom. Plans were recalculated and compared with the measurement result. The result of this study shows that the max dose of spinal cord showed significant difference after correction, and the deviation between calculation results and measurement results was reduced after correction. The method for expanding the range CT-density table, which means that the density of titanium alloy was included, can reduce the error in calculation.
Radiotherapy, Intensity-Modulated/methods* ; Titanium ; Radiotherapy Dosage ; Alloys ; Radiometry/methods* ; Radiotherapy Planning, Computer-Assisted/methods*

As a method of dosimetric verification in radiotherapy, gamma index has been widely used for evaluating dose distribution in research and clinical cases. However, for three-dimensional dose distributions, gamma index calculation is very time consuming for the computers. In this paper, based on a pre-sorting technique, we implement a parallel computing algorithm of gamma index on graphic processing unit (GPU). Dose comparisons are performed for seven cases to test our new implementation. It was shown that the GPU-based gamma index calculations achieved a speedup of ten-folds in comparison with corresponding CPU implementation without losing accuracy. The result showed that utilizing GPU parallel computing to speed up gamma index calculations could be reliable and efficient in the implementation.
Algorithms ; Computer Graphics ; Humans ; Radiometry ; methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; Software