Dose 2016

Dose to phantom to dose to water in water

The formalism to convert ionisation measured in a phantom to dose in water requires:

• Data on phantom material (available) • Chamber perturbation factors (not widely available) • Phantom conversion factor can be determined experimentally • Epoxy resin based solid phantoms shown to be equivalent to within 1% to water

To choose a suitable water- equivalent solid phantom for dosimetry:

•the depth scaling factor needs to be close to unity; namely the material needs to have effective mass attenuation coefficient close to that of water

•the phantom dose conversion factor (fluence scaling factor) to be close to unity