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Purpose: Patient-specific ridge filters can modulate proton energy to obtain a conformal dose. We describe a new framework for optimization of filter design and spot maps to meet the unique demands of FLASH radiotherapy. We demonstrate an…

We develop fixed-point algorithms for the approximation of structured matrices with rank penalties. In particular we use these fixed-point algorithms for making approximations by sums of exponentials, or frequency estimation. For the basic…

Numerical Analysis · Mathematics 2016-01-07 Fredrik Andersson , Marcus Carlsson

Accurate dose distribution prediction is crucial in the radiotherapy planning. Although previous methods based on convolutional neural network have shown promising performance, they have the problem of over-smoothing, leading to prediction…

Image and Video Processing · Electrical Eng. & Systems 2024-10-31 Xin Liao , Zhenghao Feng , Jianghong Xiao , Xingchen Peng , Yan Wang

In intensity-modulated radiation therapy, optimal intensity distributions of incoming beams are decomposed into linear combinations of leaf openings of a multileaf collimator (segments). In order to avoid inefficient dose delivery, the…

Medical Physics · Physics 2010-09-29 Antje Kiesel , Tobias Gauer

Intensity-modulated proton therapy (IMPT) offers superior dose conformity with reduced exposure to surrounding healthy tissues compared to conventional photon therapy. Improving IMPT delivery efficiency reduces motion-related uncertainties,…

Medical Physics · Physics 2025-04-15 Ya-Nan Zhu , Nimita Shinde , Bowen Lin , Hao Gao

The problem of determining the (least) fixpoint of (higher-dimensional) functions over the non-negative reals frequently occurs when dealing with systems endowed with a quantitative semantics. We focus on the situation in which the…

Logic in Computer Science · Computer Science 2026-01-23 Paolo Baldan , Sebastian Gurke , Barbara König , Florian Wittbold

In recent years, volumetric modulated arc therapy (VMAT) has been becoming a more and more important radiation technique widely used in clinical application for cancer treatment. One of the key problems in VMAT is treatment plan…

Medical Physics · Physics 2016-01-06 Yu Yang , Bin Dong , Zaiwen Wen

Objective: Intensity-modulated radiation therapy (IMRT) beam angle optimization (BAO) is a challenging combinatorial optimization problem that is NP-hard. In this study, we aim to develop a personalized BAO algorithm for IMRT that improves…

Medical Physics · Physics 2023-03-08 Peng Bao , Gong Wang , Ruijie Yang , Bin Dong

This work describes methodologies to successfully implement the Implicit Monte Carlo (IMC) scheme for thermal radiative transfer in reduced-precision floating-point arithmetic. The methods used can be broadly categorized into scaling…

Computational Physics · Physics 2025-10-27 Simon Butson , Mathew Cleveland , Alex Long , Todd Palmer

Purpose: Intensity-modulated proton therapy (IMPT) offers precise tumor coverage while sparing organs at risk (OARs) in head and neck (H&N) cancer. However, its sensitivity to anatomical changes requires frequent adaptation through online…

Within the setting of intensity modulated radiation therapy (IMRT) and the fully continuous version of IMRT called volumetric modulated radiation therapy (VMAT), we consider the problem of matching a given fluence map as well as possible in…

Medical Physics · Physics 2019-01-14 Matthew Kelly , Jacobus H. M. van Amerongen , Marleen Balvert , David Craft

Background and Purpose: Increasing the number of arcs in volumetric modulated arc therapy (VMAT) allows for better intensity modulation and may improve plan quality. However, this leads to longer delivery times, which may cause patient…

Medical Physics · Physics 2025-10-31 Nathan Torelli , Madalyne Day , Jan Unkelbach

A new strategy for radiation therapy dosimetry planning (RTDP) used to reduce dose estimation errors due to respiratory motion in breast treatment was illustrated and evaluated in this study. On CT data set acquired for breast treatment,…

Medical Physics · Physics 2021-10-20 Mazen Moussallem , Pauline Harb , Hanane Rima , Zeina Al Kattar , Saad Ayoubi

High dose-rate brachytherapy (HDRBT) is widely used for gynecological cancer treatment. Although commercial treatment planning systems (TPSs) have inverse optimization modules, it takes several iterations to adjust planning objectives to…

Medical Physics · Physics 2021-09-14 Huan Liu , Chang M Ma , Xun Jia , Chenyang Shen , Peter Klages , Kevin Albuquerque

he segment minimization problem consists of finding the smallest set of integer matrices that sum to a given intensity matrix, such that each summand has only one non-zero value, and the non-zeroes in each row are consecutive. This has…

Data Structures and Algorithms · Computer Science 2011-09-27 Therese Biedl , Stephane Durocher , Holger H. Hoos , Shuang Luan , Jared Saia , Maxwell Young

There are no computationally feasible algorithms that provide solutions to the finite horizon Risk-sensitive Constrained Markov Decision Process (Risk-CMDP) problem, even for problems with moderate horizon. With an aim to design the same,…

Optimization and Control · Mathematics 2023-03-27 Vartika Singh , Veeraruna Kavitha

Abstract Objective. Cone-beam computed tomography is becoming more and more popular in applications such as 3D dental imaging. Iterative methods compared to the standard Feldkamp algorithm have shown improvements in image quality of…

Signal Processing · Electrical Eng. & Systems 2024-11-15 Louise Friot-Giroux , Françoise Peyrin , Voichita Maxim

Purpose: To make the planning of volumetric modulated arc therapy (VMAT) faster and to explore the tradeoffs between planning objectives and delivery efficiency. Methods: A convex multicriteria dose optimization problem is solved for an…

Medical Physics · Physics 2015-05-28 David Craft , Dualta McQuaid , Jeremiah Wala , Wei Chen , Ehsan Salari , Thomas Bortfeld

Radiation therapy is considered to be one of important treatment protocols for cancers. Radiation therapy employs several beams of ionizing radiation to kill cancer tumors, but such irradiation also causes damage to normal tissues.…

Optimization and Control · Mathematics 2016-12-06 Shogo Kishimoto , Makoto Yamashita

We consider an inertial primal-dual fixed point algorithm (IPDFP) to compute the minimizations of the following Problem (1.1). This is a full splitting approach, in the sense that the nonsmooth functions are processed individually via their…

Optimization and Control · Mathematics 2016-04-20 Meng Wen , Yu-Chao Tang , Jigen Peng