PURPOSE To evaluate the utility of implanted surgical clips for detecting interfractional errors in the treatment of hepatobiliary and pancreatic cancer with postoperative radiotherapy (PORT). METHODS AND MATERIALS Twenty patients had been treated with PORT for locally advanced hepatobiliary or pancreatic cancer, from November 2014 to April 2016. Patients underwent computed tomography simulat...

Automatic segmentation of organs-at-risk (OARs) in CT scans using convolutional neural networks (CNNs) is being introduced into the radiotherapy workflow. However, these segmentations still require manual editing and approval by clinicians prior to clinical use, which can be time consuming. The aim this work was develop a tool automatically identify errors 3D OAR without ground truth. Our uses ...

The aim of this study was to compare the setup difference measured with ExacTrac X-ray 6D (ETX6D) and cone-beam computed tomography (CBCT) for non-invasive fractionated radiotherapy. Setup data were collected on a Novalis Tx treatment unit for both a head phantom and patients with intracranial tumors and a pelvic phantom and patients with prostate cancer. Initially, setup was done for a phantom...

When setting up patients via image-guided positioning for external-beam radiotherapy, one can often determine the rotational corrections needed for optimal alignment, but once measured, they are not always applied. However, in rigid-body setup calculations the optimal translational component of the setup correction will be different depending on whether rotations are included or excluded from t...

This report presents an analysis of patient setup errors resulting from inaccurately positioned wall lasers. It suggests that laser beams should agree within 0.2 degree or better with the machine axes that they are delineating. For typical simulator and treatment rooms having wall-to-isocenter distances of 3 m, this requirement is satisfied when the beam-emitting aperture is mounted within abou...

This prospective study was to assess interfractional and intrafractional errors and to estimate appropriate margins for planning target volume (PTV) by using daily cone-beam computed tomography (CBCT) guidance in nasopharyngeal carcinoma (NPC). Daily pretreatment and post-treatment CBCT scans were acquired separately after initial patient setup and after the completion of each treatment fractio...

The desire to increase the precision in radiotherapy delivery has led to the development of advanced imaging systems such as amorphous silicon (a-Si)-based electronic portal imaging, and kV and MV cone beam CT. These are used prior to the delivery of radiation to visualise the organ to be treated and to ensure that the patient setup and treatment delivery are accurate. However, little attention...

OBJECTIVE To evaluate the value of CT common rail technique for application in intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC). METHODS Twenty-seven NPC patients underwent Somatom CT scans using the Siemens CTVision system prior to the commencement of the radiotherapy sessions. The acquired CT images were registered with the planning CT images using the matching function o...

The purpose of this study was to quantify the systematic and random errors for various disease sites when daily MVCT scans are acquired, and to analyze alterna- tive off-line verification protocols (OVP) with respect to the patient setup accuracy achieved. Alignment data from 389 patients (9,418 fractions) treated at ten differ- ent anatomic sites with daily image-guidance (IG) on a helical tom...