A prototype low-cost secondary standard calorimeter for reference dosimetry with ultra-high pulse dose rates.

Objectives: Ultra-high pulse dose rate modalities present significant dosimetry challenges for ionisation chambers due to significant ion recombination. Conversely, calorimeters are ideally suited to measure high dose, short duration dose deliveries and this work describes a simple calorimeter as an alternative dosemeter for use in the clinic.

Methods: Calorimeters were constructed featuring a disc-shaped core and single sensing thermistor encased in a 3D-printed body shaped like a Roos ionisation chamber.

IPEM code of practice for high-energy photon therapy dosimetry based on the NPL absorbed dose calibration service.

The 1990 code of practice (COP), produced by the IPSM (now the Institute of Physics and Engineering in Medicine, IPEM) and the UK National Physical Laboratory (NPL), gave instructions for determining absorbed dose to water for megavoltage photon (MV) radiotherapy beams (Lillicrap et al 1990). The simplicity and clarity of the 1990 COP led to widespread uptake and high levels of consistency in external dosimetry audits. An addendum was published in 2014 to include the non-conventional conditions in Tomotherapy units.

A multi-institutional dosimetry audit of rotational intensity-modulated radiotherapy.

Background: Rotational IMRT (VMAT and Tomotherapy) has now been implemented in many radiotherapy centres. An audit to verify treatment planning system modelling and treatment delivery has been undertaken to ensure accurate clinical implementation.

Material And Methods: 34 institutions with 43 treatment delivery systems took part in the audit.

The calibration of parallel-plate electron ionization chambers at NPL for use with the IPEM 2003 code of practice: summary data.

The most recent electron dosimetry code of practice for radiotherapy written by the Institute of Physics and Engineering in Medicine was published in 2003 and is based on the NPL electron absorbed dose to water calibration service. NPL has calibrated many Scanditronix type NACP-02 and PTW Roos type 34001 parallel plate ionization chambers in terms of absorbed dose to water, for use with the code of practice. The results of the calibrations of these chamber types summarized here include the absorbed dose to water sensitivity, where the mean calibration factor standard deviations are 5.