Vero4DRT is an innovative image-guided radiotherapy system employing a C-band X-ray head with gimbal mechanics. The purposes of this study were to propose specific MC models of the linac head and multileaf collimator (MLC) for the Vero4DRT and to verify their accuracy. For a 6 MV photon beam delivered by the Vero4DRT, a simulation code was implemented using EGSnrc. The linac head model and the ...

PURPOSE To report on the physical aspects of a system in which radiotherapy functionality was added to a micro-computed tomography (microCT) scanner, to evaluate the accuracy of this instrument, and to and demonstrate the application of this technology for irradiating tumors growing within the lungs of mice. METHODS AND MATERIALS A GE eXplore RS120 microCT scanner was modified by the addition...

BACKGROUND The respiratory related target motion and setup error will lead to a large margin in the gastric radiotherapy. The purpose of this study is to investigate the dosimetric benefit and the possibility of incorporating the breath-hold (BH) technique with online image-guided radiotherapy in the adjuvant gastric cancer radiotherapy. METHODS Setup errors and target motions of 22 post-oper...

In intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT), the use of posterior oblique beams has become common. Beam attenuation by the treatment couch is not negligible when the couch is in the beam portal. In this study, we established the relationship of relative dose vs. beam angle for two Varian 21EX linacs, one equipped with the Exact couch (standard cou...

Imaging has been integral to radiotherapy for decades. However, it has been within the last 20 years that phrases such as ‘image guidance’ have become part of mainstream radiotherapy vocabulary, and the use of all available imaging modalities within radiotherapy more common. So what is meant by ‘image guidance in radiotherapy’? This was one of the questions that the National Radiotherapy Implem...

Introduction: Radiotherapy is one of the treatment options for locally advanced prostate cancer, however with standard radiation doses it is not always very effective. One of the strategies to improve the efficiency of radiotherapy is increasing the dose. In this study to increase tumor local control rates a new radiotherapy method, known as dose painting (DP) was investigated....

At the UMC Utrecht, The Netherlands, we have constructed a prototype MRI accelerator. The prototype is a modified 6 MV Elekta (Crawley, UK) accelerator next to a modified 1.5 T Philips Achieva (Best, The Netherlands) MRI system. From the initial design onwards, modifications to both systems were aimed to yield simultaneous and unhampered operation of the MRI and the accelerator. Indeed, the sim...

OBJECTIVE The real-time tumor-tracking radiotherapy system with fiducial markers has the advantage that it can be used to verify the localization of the markers during radiation delivery in real-time. We conducted a prospective Phase II study of image-guided local-boost radiotherapy for locally advanced bladder cancer using a real-time tumor-tracking radiotherapy system for positioning, and her...

BACKGROUND To determine the impact of body-mass factors (BMF) before radiotherapy and changes during radiotherapy on the magnitude of setup displacement in patients with head and neck cancer (HNC). METHODS The clinical data of 30 patients with HNC was analyzed using the alignment data from daily on-line on-board imaging from image-guided radiotherapy. BMFs included body weight, body height, a...

Abstract Radiotherapy is an important cancer treatment: in patients who are cured of cancer, radiotherapy contributes to cure around 40% cases. also has role improving symptoms individuals with incurable cancer. Whereas palliative typically given over 1–10 treatments, radical treatments can extend 4–8 weeks. Radiation often delivered externally by machines called linear accelerators. I...