BS EN ISO 28057:2021

What is ISO 28057 about?  

ISO 28057 is an international standard on clinical dosimetry to ensure the safe application of TL dosimetry in the radiation therapy of cancer. 

ISO 28057 describes rules for the procedures, applications, and systems of thermoluminescence dosimetry (TLD) for dose measurements according to the probe method. It is particularly applicable to solid “TL detectors,” i.e., rods, chips, and microcubes, made from LiF: Mg, Ti or LiF: Mg, Cu, P in crystalline or polycrystalline form. 

ISO 28057 applies to dosimetry in teletherapy with both photon radiation from 20 keV to 50 MeV and electron radiation from 4 MeV to 25 MeV, as well as in brachytherapy with photon-emitting radionuclides. These applications are complementary to the use of ionization chambers. 

The essential aim of ISO 28057 is to specify the procedures and to carry out corrections that allow one to achieve a repeatability of the indicated value within a fraction of a percent and thus total uncertainty of measurement of a few percent, as in ionization chamber dosimetry. 

Note: These procedures are not applicable to LiF powders because their use requires special procedures. 

Who is ISO 28057 for? 

ISO 28057 on clinical dosimetry is useful for: 

• Medical physicists 
• Radiation Oncologist 
• Dosimetrist 

Why should you use ISO 28057?  

The main disadvantage of thermoluminescence (TL) detectors is that, prior to each dosimetry application, they must be regenerated by a pre-irradiation annealing procedure. From this mean alteration, a correction factor can be derived. 

ISO 28057 provides you with the procedures, applications, and systems of thermoluminescence dosimetry (TLD) detectors for photon and electron radiations in radiotherapy. 

The rules described by ISO 28057 helps you to improve the reliability and the accuracy indispensable in clinical dosimetry to ensure that machines delivering radiation to patients are accurate and properly calibrated. 

What is changed since the last update?  

BS EN ISO 28057:2021 supersedes ISO 28057:2014. BS EN ISO 28057:2021 includes some technical changes with respect to ISO 28057:2014. These include: 

• The clause on terms and definitions and the clause on rules for TLD measurement procedures, including quality assurance measurements at clinical accelerators, have been complemented and sharpened to ensure the safe application of TL dosimetry in the radiation therapy of cancer 
• Batch dependent changes of the kQ values have been correlated with the simultaneously occurring mass density variations of TL discs 
• The response of TL materials to the neutrons, occurring within and around photon beams in megavoltage radiotherapy due to the photonuclear effect and eventually generating considerable components of the indicated values, has been dealt with in more detail 
• It is highlighted that the kE values of clinical electron beams are energy independent 
• Recent experimental results concerning the contribution of “intrinsic effects” to the response of TL detectors have been considered  
• The French title and the numbering of some subclauses of 5.4 have been corrected; Table 9 has been equipped with a heading