[The EQUAL-ESTRO external quality control laboratory in France].

Purpose: The EQUAL-ESTRO laboratory was set up in 1998 to perform external audits of radiotherapy beams for all the European centres. Until the end of the year 2003, it was funded by EC projects. The external quality control is based on measurements performed with thermoluminescent dosimeters (TLD) sent by postal mail to the participating centre in order to be irradiated on axis in reference conditions and in conditions close to clinical conditions for photon and electron beams.

The ESTRO-EQUAL Quality Assurance Network for photon and electron radiotherapy beams in Germany.

Background: In 1998 an ESTRO Quality Assurance Network for radiotherapy (EQUAL) has been set up for 25 European countries for photon and electron beams in reference and non-reference conditions.

Material And Methods: Measurements are done using LiF powder (DTL937-Philitech, France) that is processed with the PCL3 automatic reader (Fimel-PTW). The participating centers irradiate the TLDs with an absorbed dose of 2 Gy according to the clinical routine.

External audits of electron beams using mailed TLD dosimetry: preliminary results.

Aim: A feasibility study has been performed to investigate the possibility of using mailed thermoluminescence dosimetry (TLD) for external audits of clinical electron beams in Europe.

Methods: In the frame of the EC Network Project for Quality Assurance in Radiotherapy, instruction sheets and mailing procedures have been defined for mailed TLD dosimetry using the dedicated holder developed by a panel of experts of the International Atomic Energy Agency (IAEA). Three hundred and thirty electron beam set-ups have been checked in the reference centres and some local centres of the EC Network Project and in addition through the centres participating to the EORTC Radiotherapy Group trial 22922.

Energy correction factors of LiF powder TLDs irradiated in high-energy electron beams and applied to mailed dosimetry for quality assurance networks.

Absorbed dose determination with thermoluminescent dosimeters (TLDs) generally relies on calibration in 60Co gamma-ray reference beams. The energy correction factor fCo(E) for electron beams takes into account the difference between the response of the TLD in the beam of energy E and in the 60Co gamma-ray beam. In this work, fCo(E) was evaluated for an LiF powder irradiated in electron beams of 6 to 20 MeV (Varian 2300C/D) and 10 to 50 MeV (Racetrack MM50), and its variation with electron energy, TLD size and nature of the surrounding medium was also studied for LiF powder.

The ESTRO-QUALity assurance network (EQUAL).

Background And Purpose: ESTRO has set up a Quality Assurance network (EQUAL) to check the dose delivered on axis in reference and non-reference conditions for external radiotherapy. The external audits covered by the network are based on measurements made with mailed thermoluminescent dosimeters (TLD).

Material And Methods: The TLD consist of LiF powder type DTL 937 read with a PCL 3 automatic TLD reader.