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...

Quantification of the setup errors is vital to define appropriate setup margins preventing geographical misses. The no-action-level (NAL) correction protocol reduces the systematic setup errors and, hence, the setup margins. The manual entry of the setup corrections in the record-and-verify software, however, increases the susceptibility of the NAL protocol to human errors. Moreover, the impact...

Introduction Patient set-up optimization is required in radiotherapy to fill the accuracy gap between personalized treatment planning and uncertainties in the irradiation set-up. In this study, we aimed to develop a new method based on neural network to estimate patient geometrical setup using 4-dimensional (4D) XCAT anthropomorphic phantom. Materials and Methods To access 4D modeling of motion...

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...

PURPOSE The aim of this study was to assess the residual setup error of different image-guidance (IG) protocols in the alignment of patients with head and neck cancer. The protocols differ in the percentage of treatment fractions that are associated with image guidance. Using data from patients who were treated with daily IG, the residual setup errors for several different protocols are retrosp...

introduction superficial x-ray therapy is one of the most important treatment methods in radiotherapy especially in the treatment of superficial skin lesions (up to 300 kvp). quality of the x-ray beam that can be expressed by half-value layer (hvl), are important indices for this type of treatment effective energy of photon and homogeneity coefficient (hc). materials and methods the hc of the s...

We have developed a computerized method for estimating patient setup errors in portal images based on localized pelvic templates for prostate cancer radiotherapy. The patient setup errors were estimated based on a template-matching technique that compared the portal image and a localized pelvic template image with a clinical target volume produced from a digitally reconstructed radiography (DRR...

background: to correct patient positioning errors (setup errors) during prostate cancer treatment using epid and fiducial gold markers, to improve the accuracy of the dose delivery in these patients. materials and methods: fifteen patients with localized prostate carcinoma after implantation of fiducial gold markers in their prostate gland underwent the five-field imrt planning technique. the p...

BACKGROUND Image guided radiotherapy (IGRT) is an essential pre-requisite for delivering high precision radiotherapy. We compared daily variation detected by two non-ionizing imaging modalities (surface imaging and trans-abdominal ultrasound, US) to verify prostate patient setup and internal organ variations. METHODS Forty patients with organ confined prostate cancer and candidates to curativ...

Dose distributions in HN-IMRT are complex and may be sensitive to the treatment uncertainties. The goals of this study were to evaluate: 1) dose differences between plan and actual delivery and implications on margin requirement for HN-IMRT with rigid setup errors; 2) dose distribution complexity on setup error sensitivity; and 3) agreement between average dose and cumulative dose in fractionat...