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. However, the 1990 COP lacked detailed recommendations for calibration conditions, and the corresponding nomenclature, to account for modern treatment units with different reference fields, including small fields as described in IAEA TRS483 (International Atomic Energy Agency (IAEA) 2017, Vienna). This updated COP recommends the irradiation geometries, the choice of ionisation chambers, appropriate correction factors and the derivation of absorbed dose to water calibration coefficients, for carrying out reference dosimetry measurements on MV external beam radiotherapy machines. It also includes worked examples of application to different conditions. The strengths of the 1990 COP are retained: recommending the NPL2611 chamber type as secondary standard; the use of tissue phantom ratio (TPR) as the beam quality specifier; and NPL-provided direct calibration coefficients for the user's chamber in a range of beam qualities similar to those in clinical use. In addition, the formalism is now extended to units that cannot achieve the standard reference field size of 10 cm × 10 cm, and recommendations are given for measuring dose in non-reference conditions. This COP is designed around the service that NPL provides and thus it does not require the range of different options presented in TRS483, such as generic correction factors for beam quality. This approach results in a significantly simpler, more concise and easier to follow protocol.

Videoconferencing psychotherapy: a systematic review.

Individuals with mental health problems may face barriers to accessing effective psychotherapies. Videoconferencing technology, which allows audio and video information to be shared concurrently across geographical distances, offers an alternative that may improve access. We conducted a systematic literature review of the use of videoconferencing psychotherapy (VCP), designed to address 10 specific questions, including therapeutic types/formats that have been implemented, the populations with which VCP is being used, the number and types of publications related to VCP, and available satisfaction, feasibility, and outcome data related to VCP. After electronic searches and reviews of reference lists, 821 potential articles were identified, and 65 were selected for inclusion. The results indicate that VCP is feasible, has been used in a variety of therapeutic formats and with diverse populations, is generally associated with good user satisfaction, and is found to have similar clinical outcomes to traditional face-to-face psychotherapy. Although the number of articles being published on VCP has increased in recent years, there remains a need for additional large-scale clinical trials to further assess the efficacy and effectiveness of VCP.