Defining field output factors in small fields based on dose area product measurements: A feasibility study.

Background: Dose area product in water (DAP) in small fields relies on the use of detectors with a sensitive area larger than the irradiation field. This quantity has recently been used to establish primary standards down to 5 mm field size, with an uncertainty smaller than 0.7%.

End-to-end quality assurance for stereotactic radiotherapy with Fricke-Xylenol orange-Gelatin gel dosimeter and dual-wavelength cone-beam optical CT readout.

Purpose: The end-to-end (E2E) quality assurance (QA) test is a unique tool for validating the treatment chain undergone by patients in external radiotherapy. It should be conducted in three dimensions (3D) to get accurate results. This study aims to implement these tests with Fricke-Xylenol orange-Gelatin (FXG) gel dosimeter and a newly developed dual-wavelength reading method on the Vista16™ optical Computed Tomography (CT) scanner (ModusQA) for three treatment techniques in stereotactic radiotherapy, on Novalis (Varian) and CyberKnife (Accuray) linear accelerators.

Preliminary dosimetric characterization of EDBreast gel.

. EDBreast gel is an alternative Fricke gel dosimeter, read by Magnetic Resonance Imaging, in which sucrose is added to lower diffusion effects. This paper aims at determining the dosimetric characteristics of this dosimeter.

Dose area product primary standards established by graphite calorimetry at the LNE-LNHB for small radiation fields in radiotherapy.

Purpose: To present primary standards establishment in terms of Dose Area Product (DAP) for small field sizes.

Methods: A large section graphite calorimeter and two plane-parallel ionization chambers were designed and built in-house. These chambers were calibrated in a 6MV FFF beam at the maximum dose rate of 1400 UM/min for fields defined by specifically designed circular collimators of 5, 7.

Fricke-Xylenol orange-Gelatin gel characterization with dual wavelength cone-beam optical CT scanner for applications in stereotactic and dynamic radiotherapy.

Purpose: This study is about the development of a new dual wavelength reading method of Fricke-Xylenol orange-Gelatin (FXG) gel dosimeters on the Vista16™ optical Computed Tomography (CT) scanner to perform 3D dose distribution measurements in stereotactic and dynamic radiotherapy treatments.

Methods: The dosimetric characteristics of an optimized FXG gel composition and its optical CT readout have been evaluated. A dual wavelength reading method has been developed on the CT scanner at wavelengths 590 nm and 633 nm.

Report of IRPA task group on issues and actions taken in response to the change in eye lens dose limit.

In 2018, the International Radiation Protection Association (IRPA) established its third task group (TG) on the implementation of the eye lens dose limit. To contribute to sharing experience and raising awareness within the radiation protection community about protection of workers in exposure of the lens of the eye, the TG conducted a questionnaire survey and analysed the responses. This paper provides an overview of the results of the questionnaire.

Feasibility of using a dose-area product ratio as beam quality specifier for photon beams with small field sizes.

Purpose: To investigate the feasibility of using the ratio of dose-area product at 20 cm and 10 cm water depths (DAPR) as a beam quality specifier for radiotherapy photon beams with field diameter below 2 cm.

Methods: Dose-area product was determined as the integral of absorbed dose to water (D) over a surface larger than the beam size. 6 MV and 10 MV photon beams with field diameters from 0.

Calibration of helical tomotherapy machine using EPR/alanine dosimetry.

Purpose: Current codes of practice for clinical reference dosimetry of high-energy photon beams in conventional radiotherapy recommend using a 10 x 10 cm2 square field, with the detector at a reference depth of 10 cm in water and 100 cm source to surface distance (SSD) (AAPM TG-51) or 100 cm source-to-axis distance (SAD) (IAEA TRS-398). However, the maximum field size of a helical tomotherapy (HT) machine is 40 x 5 cm2 defined at 85 cm SAD. These nonstandard conditions prevent a direct implementation of these protocols.

Analysis of computational problems expressing the overall uncertainties: photons, neutrons and electrons.

In the frame of the EU Coordination Action CONRAD (coordinated network for radiation dosimetry), WP4 was dedicated to work on computational dosimetry with an action entitled 'Uncertainty assessment in computational dosimetry: an intercomparison of approaches'. Participants attempted one or more of eight problems. This paper presents the results from problems 4-8-dealing with the overall uncertainty budget estimate; a short overview of each problem is presented together with a discussion of the most significant results and conclusions.

Intercomparison of active personal dosemeters in interventional radiology.

The use of active personal dosemeters (APD) in interventional radiology was evaluated by Working Group 9 (Radiation protection dosimetry of medical staff) of the CONRAD project, which is a Coordination Action supported by the European Commission within its sixth Framework Programme. Interventional radiology procedures can be very complex and they can lead to relatively high doses to personnel who stand close to the primary radiation field and are mostly exposed to radiation scattered by the patient. For the adequate dosimetry of the scattered photons, APDs must be able to respond to low-energy [10-100 keV] and pulsed radiation with relatively high instantaneous dose rates.