Retrospective evaluation of CTV to PTV margins using CyberKnife in patients with thoracic tumors.

The objectives of this study were to estimate global uncertainty for patients with thoracic tumors treated in our center using the CyberKnife VSI after placement of fiducial markers and to compare our findings with the standard CTV to PTV margins used to date. Datasets for 16 patients (54 fractions) treated with the CyberKnife and the Synchrony Respiratory Tracking System were analyzed retrospectively based on CT planning, tracking information, and movement data generated and saved in the logs files by the system. For each patient, we analyzed all the main uncertainty sources and assigned a value.

Initial evaluation of intrafraction motion using frameless CyberKnife VSI system.

Aim: To analyze intrafraction movement in patients undergoing frameless robotic radiosurgery and evaluate the influence of image acquisition frequency on global accuracy.

Background: Stereotactic radiosurgery requires high spatial accuracy in dose delivery. In conventional radiosurgery, a rigid frame is used to guarantee a correct target alignment and no subsequent movement.

Experience with the CyberKnife for intracranial stereotactic radiosurgery: analysis of dosimetry indices.

We evaluated coverage, dose homogeneity, dose conformity, and dose gradient in CyberKnife VSI treatment plans. Several dosimetric indices were calculated, and the results were compared with those of previous publications. The effect of target volume on the radiosurgical treatment indices selected was also investigated.

Study of the uncertainty in the determination of the absorbed dose to water during external beam radiotherapy calibration.

To achieve a good clinical outcome in radiotherapy treatment, a certain accuracy in the dose delivered to the patient is required. Therefore, it is necessary to keep the uncertainty in each of the steps of the process inside some acceptable values, which implies a global uncertainty as low as possible. This work is focused on the uncertainty evaluation of absorbed dose to water in the routine calibration for clinical beams, in the range of energies used in external radiotherapy.

Statistical analysis of dose-volume and dose-wall histograms for rectal toxicity following 3D-CRT in prostate cancer.

The purpose of this paper is to determine the correlation between dose-volume histogram (DVH) and dose wall-histogram (DWH) in the evaluation of rectal complications for prostate cancer patients treated with three-dimensional conformal radiotherapy (3D-CRT). A retrospective analysis of DVHs and DWHs of a subset of 25 prostate cancer patients treated with 3D-CRT was performed. For every patient the rectum and the rectal wall (inner and outer surface) were contoured.

Impact of mean rectal dose on late rectal bleeding after conformal radiotherapy for prostate cancer: dose-volume effect.

Purpose: To identify the clinical and dosimetric factors predictive of a greater risk of Grade 2 or worse late rectal bleeding in patients with localized prostate cancer treated with three-dimensional conformal radiotherapy in a prospective dose-escalation study.

Methods And Materials: We performed a retrospective analysis of the clinical records and dose-volume histograms of 107 patients with Stage T1c-T3 prostate cancer treated at our institution with three-dimensional conformal radiotherapy who had a minimal follow-up of 1 year. Of the 107 patients, 21 were treated at dose level 1 (70.