Regional Training Course on TRS 483: IAEA/AAPM Code of Practice on Small Static Fields Used in External Beam Radiotherapy

Application Deadline for Nominee(s) of Invited IAEA Member States: 31 August 2018

Background

Modern radiotherapy has increased substantially the use of small radiation fields like those used in various forms of Stereotactic Radiotherapy (SRT), Stereotactic Body Radiotherapy (SBRT) Stereotactic Radiosurgery (SRS) and Intensity Modulated Radiation Therapy (IMRT). These treatments are not only performed with specialized, dedicated machines such as TomoTherapy, CyberKnife or GammaKnife, but also with conventional, non-dedicated accelerators equipped with high-resolution multi-leaf collimators.

In radiotherapy it is essential that the dose delivered to the patient is known accurately so that the correct amount of radiation is delivered that kills the cancer cells while at the same time sparing healthy tissue. Therefore, a key step in the radiotherapy process is the requirement for consistent reference dosimetry traceable to metrological primary standards and to enable common procedures within a country to be followed for reference dosimetry. For conventional radiotherapy this has been achieved by universally adopted Codes of Practice such as IAEA TRS 398 (IAEA, Vienna, 2000). However, the standard Codes of Practice are based on the use of a 10 cm x 10 cm reference field that may not be achievable using some modern specialized machines.

A joint working group between the IAEA and AAPM (American Association of Physicists in Medicine) has written a new small field Code of Practice (TRS 483). The aim of this course is to teach how to implement the new Code of Practice in the clinic.

Purpose

The purpose of the course is to train clinical medical physicists in Member States on how to implement the new IAEA/AAPM Code of Practice on small field dosimetry.

Expected Outputs

The course is an opportunity for medical physicists from Member States to get first-hand information on the dosimetry of small fields in radiotherapy. It will be beneficial to clinical medical physicists working in radiotherapy modalities using small fields such as Stereotactic Radiotherapy (SRT), Stereotactic Body Radiotherapy (SBRT) Stereotactic Radiosurgery (SRS) and Intensity Modulated Radiation Therapy (IMRT).

Scope and Nature

This five-day course will consist of lectures, presentations, discussion and at the weekend the participants will perform practical sessions in the local radiotherapy centre.

The topics to be covered include the following:

• Physics and challenges of small fields MV photon beams
• Description of the new IAEA/AAPM Code of Practice for dosimetry of static small photon fields
• Discussion on small field detectors
• Absorbed dose to water standards for small fields
• Machine Specific Reference dosimetry
• Output factors: Definition, measurement and correction
• Relative dose measurements in small fields