PURPOSE To investigate the feasibility of constant dose rate volumetric modulated arc therapy (CDR-VMAT) in the treatment of nasopharyngeal cancer (NPC) patients and to introduce rotational arc radiotherapy for linacs incapable of dose rate variation. MATERIALS AND METHODS Twelve NPC patients with various stages treated previously using variable dose rate (VDR) VMAT were enrolled in this stud...

This study evaluated the setup uncertainties for brain sites when using BrainLAB's ExacTrac X-ray 6D system for daily pretreatment to determine the optimal planning target volume (PTV) margin. Between August 2012 and April 2015, 28 patients with brain tumors were treated by daily image-guided radiotherapy using the BrainLAB ExacTrac 6D image guidance system of the Novalis-Tx linear accelerator....

AIM This study compared the dosimetric impact between prostate IMRT and VMAT due to patient's weight loss. BACKGROUND Dosimetric variation due to change of patient's body contour is difficult to predict in prostate IMRT and VMAT, since a large number of small and irregular segmental fields is used in the delivery. MATERIALS AND METHODS Five patients with prostate volumes ranging from 32.0 t...

PURPOSE GBM recurrence primarily occurs inside or near the high-dose radiation field of original tumor site requiring greater than 100 Gy to significantly improve local control. We utilize 4π non-coplanar radiotherapy to test the feasibility of planning target volume (PTV) margin expansions or extreme dose escalations without incurring additional radiation toxicities. METHODS 11 GBM patients ...

In prostate radiotherapy, the influence of bladder volume variation on the dose absorbed by the target volume and organs at risk is significant and difficult to predict. In addition, the resolution of a typical medical image is insufficient for visualizing the bladder wall, which makes it more difficult to precisely evaluate the dose to the bladder wall. This simulation study aimed to quantitat...

BACKGROUND AND PURPOSES To compare the dosimetry for the left-sided breast cancer treatment using five different radiotherapy techniques. MATERIALS AND METHODS Twenty patients with left sided breast cancer were treated with conservative surgery followed by radiotherapy. They were planned using five different radiotherapy techniques, including: 1) conventional tangential wedge-based fields (TW...

Introduction: In radiation therapy of lung tumors, respiratory motion causes target moving, so a larger margin is needed to cover the clinical target volume (CTV). With the margin increasing, a larger volume of normal tissue will be exposed to high-dose.  In this study, dosimetric parameters of normal lung tissue were compared between gated and conventional radiotherapy (RT), u...