Background: stereotactic body radiotherapy (SBRT) has emerged as an effective treatment for localized prostate cancer. However, prostate-specific antigen (PSA) kinetics after SBRT has not been well characterized. The objective of the current study is to analyze the rate of PSA decline and PSA nadir following hypofractonated SBRT in localized prostate cancer. Materials and Methods: From 2008...

OBJECTIVE The low alpha/beta ratio of prostate cancer suggests that hypofractionated schemes of dose-escalated radiotherapy should be advantageous. We report our experience using stereotactic body radiation therapy (SBRT) for the primary treatment of prostate cancer to assess efficacy and toxicity. METHODS From 2007 to 2010, 70 patients (51 % low risk, 31 % intermediate risk, and 17 % high ri...

Definitive radiotherapy is an important alternative treatment for meningioma patients who are inoperable or refuse surgery. We evaluated the efficacy and toxicity of CyberKnife-based stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (hSRT) as first-line treatments for intracranial meningiomas that were diagnosed using magnetic resonance imaging (MRI) and/or computed...

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. Frameless radiosurg...

The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife(®)) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced CE at t...

In today’s operating theatres, tracking devices are widely employed. One example is the tracking of breathing motion for image guided radiation therapy. For respiratory motion compensation with the robotic CyberKnife® system, the motion of markers on the patient’s chest is measured and related to the tumor motion [2, 3]. However, the measurements are subject to noise that can hamper further sig...

AIM The Monte Carlo dose calculation algorithm yields accurate dose distributions in heterogeneous media and interfaces. The Monte Carlo calculation algorithm provided in the Multiplan Cyberknife treatment planning system (Accuray, Sunnyvale, CA, USA) has five different dose-smoothing algorithms in it. As the principle of smoothing of these algorithms is different, they can produce a disparity ...

BACKGROUND To identify the value of the pre-treatment apparent diffusion coefficient (ADC) derived from diffusion weighted imaging (DWI) in predicting the overall survival (OS) for locally advanced pancreatic cancer (LAPC) treated with Cyberknife followed by sequential S-1 chemotherapy. METHODS Patients with UICC-T4 LAPC who underwent DWI scan (3.0 Tesla) using two b-values (0, 600 s/mm2) in ...

BACKGROUND Combination therapy using external-beam radiotherapy (EBRT) with a brachytherapy boost has demonstrated superior biochemical control than dose-escalated EBRT alone. Whereas brachytherapy is disadvantageous because it is an invasive procedure, stereotactic body-radiotherapy (SBRT) using CyberKnife could emulate the dose distribution of brachytherapy and is a non-invasive and safe moda...

OBJECTIVE To investigate the efficacy and safety of fractionated stereotactic radiosurgery for large brain metastases (BMs). METHODS Between June 2011 and December 2013, a total of 38 large BMs >3.0 cm in 37 patients were treated with fractionated Cyberknife radiosurgery. These patients comprised 16 men (43.2%) and 21 women, with a median age of 60 years (range, 38-75 years). BMs originated f...