Intrafraction Motion in Surface-Guided Breast Radiation Therapy and its Implications on a Single Planning Target Volume Margin Strategy.

Purpose: This study quantifies intrafraction motion in surface-guided radiation therapy (SGRT) for breast cancer and considers the need for individualized intrafraction motion measures when calculating planning target volume (PTV) margins.

Methods And Materials: SGRT was used to assess intrafraction motion in consecutive patients according to (1) site irradiated (whole-breast/chest wall vs whole-breast/chest wall + regional lymph nodes) and (2) the use of deep inspiration breath hold versus free breathing. Intrafraction motion variation was evaluated throughout the treatment course for all cases.

Estimation of the relative biological effectiveness for double strand break induction of clinical kilovoltage beams using Monte Carlo simulations.

Background: The Relative Biological Effectiveness (RBE) of kilovoltage photon beams has been previously investigated in vitro and in silico using analytical methods. The estimated values range from 1.03 to 1.

Clinical treatment planning for kilovoltage radiotherapy using EGSnrc and Python.

Kilovoltage radiotherapy dose calculations are generally performed with manual point dose calculations based on water dosimetry. Tissue heterogeneities, irregular surfaces, and introduction of lead cutouts for treatment are either not taken into account or crudely approximated in manual calculations. Full Monte Carlo (MC) simulations can account for these limitations but require a validated treatment unit model, accurately segmented patient tissues and a treatment planning interface (TPI) to facilitate the simulation setup and result analysis.

Performance of a low gain avalanche detector in a medical linac and characterisation of the beam profile.

Low gain avalanche detectors can measure charged particle fluences with high speed and spatial precision, and are a promising technology for radiation monitoring and dosimetry. A detector has been tested in a medical linac where single particles were observed with a time resolution of 50 ps. The integrated response is similar to a standard ionising chamber but with a spatial precision twenty times finer, and a temporal precision over 100 million times better, with the capability to measure the charge deposited by a single linac pulse.

Energy and dose dependence of GafChromic EBT3-V3 film across a wide energy range.

Aim: To determine the energy and dose dependence of GafChromic EBT3-V3 film over an energy range 0.2 mm Al HVL to 6 MV.

Background: The decay scheme of a brachytherapy source may be complex and the spectrum of energy can be wide.