Plan delivery quality assurance for CyberKnife: Statistical process control analysis of 350 film-based patient-specific QAs.

Purpose: Robotic radiosurgery requires plan delivery quality assurance (DQA) but there has never been a published comprehensive analysis of a patient-specific DQA process in a clinic. We proposed to evaluate 350 consecutive film-based patient-specific DQAs using statistical process control. We evaluated the performance of the process to propose achievable tolerance criteria for DQA validation and we sought to identify suboptimal DQA using control charts.

CyberKnife® M6™: Peripheral dose evaluation for brain treatments.

Purpose: This study evaluates the peripheral dose (PD) delivered to healthy tissues for brain stereotactic radiotherapy treatments (SRT) performed with a CyberKnife M6™ Robotic Radiosurgery System and proposes a model to estimate PD before treatment.

Method: PD was measured with thermoluminescent dosimeters. Measurements were performed to evaluate the influence of distance, collimator type (fixed or Iris™) and aperture size on PD for typical brain treatment plans simulated on an anthropomorphic phantom.

[Expected benefit of lymph node and seminal vesical dissection to decrease high-risk prostate cancer radiotherapy].

Purpose: In case of pelvic lymph node and seminal vesicle dissection followed by prostate cancer intensity-modulated radiotherapy, the objective of the study was to evaluate the dosimetric benefit of reducing the target volume.

Patients And Methods: A total of 25 patients with high-risk prostate cancer had surgery first followed by intensity-modulated radiotherapy and androgen deprivation. Four treatment planning were simulated for each patient, based on two CT scans performed before and after surgery.

[Which IMRT? From "step and shoot" to VMAT: physicist point of view].

Intensity-modulated radiation therapy (IMRT) is essential to have a dose distribution matching with the planning target volume (PTV) in case of concave-shape target. Today IMRT delivery techniques with linear accelerator can be divided into two classes: techniques with fixed gantry, called "step and shoot" (S&S) and "sliding window" (SW), and rotational techniques, called intensity modulated arc therapy (IMAT) and volumetric modulated arc therapy (VMAT). We discuss about constraints for IMRT implementation from dosimetric planning to treatment delivery.