AIMS AND BACKGROUND Conventional radiotherapy in inoperable cholangiocarcinoma is limited by radiotolerance of the surrounding tissues. The aim of our dosimetric study was an evaluation of intensity-modulated radiotherapy in the treatment of inoperable bile duct carcinoma. METHODS Four patients with inoperable cholangiocarcinoma treated by self-expandable stent placed to the biliary tree and ...

PURPOSE Linac parameters potentially influencing the delivery quality of IMRT and VMAT plans are investigated with respect to threshold ranges, consequently to be considered in a linac based quality assurance procedure. Three commercially available 2D arrays are used to further investigate the influence of the measurement device. METHODS Using three commercially available 2D arrays (Mx: Matri...

BACKGROUND It is currently unclear whether the superior normal organ-sparing effect of intensity-modulated radiotherapy (IMRT) compared with 3-dimensional radiotherapy (3D) has a clinical impact on survival and cardiopulmonary mortality in patients with esophageal cancer (EC). METHODS The authors identified 2553 patients aged > 65 years from the Surveillance, Epidemiology, and End Results (SE...

In this paper, we deal with the effects of interfractional organ motion during radiation therapy. We consider two problems: first, treatment plan evaluation in the presence of motion, and second, the incorporation of organ motion into IMRT optimization. Concerning treatment plan evaluation, we face the problem that the delivered dose cannot be predicted with certainty at the time of treatment p...

We use robust optimization techniques to formulate an IMRT treatment planning problem in which the dose matrices are uncertain, due to both dose calculation errors and interfraction positional uncertainty of tumour and organs. When the uncertainty is taken into account, the original linear programming formulation becomes a second-order cone program. We describe a novel and efficient approach fo...

PURPOSE New multidimensional dose comparison parameters, normalized agreement test (NAT) values and the NAT index, are introduced and compared with an ideal dose comparison parameter. In this article, we analyze a clinically based two-dimensional (2D) quantitative dose comparison case using a wide range of new and old comparison tools. In doing so, we address the benefits and limitations of man...

BACKGROUND Parameter optimization in the process of inverse treatment planning for intensity modulated radiation therapy (IMRT) is mainly conducted by human planners in order to create a plan with the desired dose distribution. To automate this tedious process, an artificial intelligence (AI) guided system was developed and examined. METHODS The AI system can automatically accomplish the opti...

This paper presents a new method for accelerating intensity-modulated radiation therapy (IMRT) optimization using voxel sampling. Rather than calculating the dose to the entire patient at each step in the optimization, the dose is only calculated for some randomly selected voxels. Those voxels are then used to calculate estimates of the objective and gradient which are used in a randomized vers...

The purpose of this study is to develop a system to automatically generate stowage plan for large containerships. The system consists of three modules: stowage plan generator, stability module and optimization engine. This paper presents the architecture and the work of the first module stowage plan generator, which is used to automatically generate a feasible stowage plan with reasonable crane...