This paper introduces a new notion related to the traveling salesperson problem (TSP) — the notion of the TSP ratio. The TSP ratio of a TSP instance I is the sum of the marginal values of the nodes of I divided by the length of the optimal TSP tour on I, where the marginal value of a node i ∈ I is the difference between the length of the optimal tour on I and the length of the optimal tour on I...

This study was to evaluate the interfractional and intrafractional setup errors and baseline shifts of golden fiducial markers in patients receiving postoperative radio- therapy (RT) using cone-beam computed tomography (CBCT) in order to calculate PTV margins for patients with liver cancer. Twelve patients with liver tumors under- went postoperative RT. CBCT images were acquired before and afte...

background and aim: generally, in patients with cervical cancer, careful preliminary evaluation is necessary for avoiding improper surgical procedures and making effective clinical decisions for treatment. the aim of this study was to determine surgeons’ errors, which necessitate a combination of surgery and radiotherapy for cervical cancer patients.    methods: in this retrospective study, med...

Background Delivering training to participating sites is an essential part of successful trial setup especially when new techniques, treatments or technologies are involved. RAIDER is a multicentre (> 30 NHS Trusts) phase II trial of complex radiotherapy for muscle invasive bladder cancer. The radiotherapy techniques were developed at a single UK NHS site and in addition to written materials id...

CONTEXT Daily setup errors and changes in body habitus during external beam radiotherapy can result in interfraction variation, contributing to uncertainties in treatment delivery. The conventional method of patient positioning using external skin markings is inadequate in reducing these interfraction variations. OBJECTIVE To evaluate use of on-board imaging with daily kV-kV image matching to...

Introduction: Successful radiotherapy requires the precise application of a radiation dose to cancerous tissue, which can be achieved by the design of proper treatment methods by radiotherapy physicists. Tasks performed by radiotherapy physicists include verifying the accuracy of dose calculations, correct treatment planning and the proper functioning of accelerators. They are...