Standards Development

Scope

This International Standard specifies the performance requirements of radiotherapy dosimeter, intended for the measurement of absorbed dose to water or air kerma (and their rates and spatial distributions) in photon, electron, proton or light and heavy ion radiation field as used in radiotherapy.

The dose monitoring system incorporated in radiotherapy treatment machines are not covered by this standard, neither are the re-entrant ionization chamber used for brachytherapy source calibration and constancy check devices.

This standard is applicable to the following types of dosimeter:

a)      field-class dosimeter normally used for

1)      the measurement of kerma or dose in a radiation beam, either in air or in a phantom;

2)      relative dose distribution measurements with a scanning system such as an automatic water phantom.

3)      in vivo skin surface or intracavitary measurements of dose on patient.

b)      reference-class dosimeter normally used for dose determination under reference conditions or for the calibration of field-class dosimeter;

NOTE reference-class dosimeter may be used as field-class dosimeter.

c)      solid-state dosimeter, where the solid-state detector is intended for operation at zero bias voltage, normally used for

1)      relative dose distribution measurements with a scanning system such as an automatic water phantom;

2)      point-dose measurements in a solid-state phantom or automatic water phantom.

The object of this standard is:

–        to establish requirements for a satisfactory level of performance for radiotherapy dosimeter;

–        to standardize methods for the determination of compliance with this level of performance.

Three levels of performance are specified:

–        a lower level of performance applying to field-class dosimeter;

–        a higher level of performance applying to reference-class dosimeter;

–        a specific level of performance applying to dosimeters where at least one detector assembly is a solid-state detector.

This may also be designated as solid-state class