Publications by authors named "Gregory Bolard"
Purpose: Image guided radiotherapy (IGRT) improves patient positioning for treatment delivery at the cost of an additional dose. This work aimed to calculate the effective dose (as an indicator of dose) for head & neck (H&N) and breast IGRT treatments by implementing dose calculation models to determine the dose distributions.
Methods: The kV dose-models were created for the IGRT systems of Elekta Synergy (XVI) and Varian Clinac (OBI) linear accelerators within Philips Pinnacle TPS.
Purpose: New definitions for some dosimetric parameters for use in quality assurance of flattening filter free (FFF) beams generated by medical linear accelerators have been suggested. The present study aims to validate these suggestions and to propose possible reference levels.
Methods: The main characteristics of FFF photon beams were described in terms of: field size, penumbra, unflatness, slope, and peak-position parameters.
Article Synopsis
- The study investigates how computing parameters and the positioning of volumes of interest (VOI) affect the measurement of the 3D noise power spectrum (NPS)in imaging systems.
- The analysis was conducted using a water phantom on two different MDCT scanners, focusing on understanding how noise varies in different directions and ensuring accurate NPS estimation through optimal VOI dimensions and location.
- Results highlight the importance of consistent measurement approaches, as VOI size and location significantly impact NPS, especially in non-stationary images, underlining the need for standardized methods to evaluate CT image quality.
Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short-lived radioisotopes other than 18F and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery-LS (D-LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2-1994 standards.
View Article and Find Full Text PDF