Breast radiotherapy phantom design for the START trial

The design of phantoms for use in radiotherapy involves a number of complex issues. This paper describes breast and chest wall phantoms that have been designed and constructed for the START trial. Four phantoms have been manu factured, including two two-dimensional phantoms used on the first round of audit visits to assess the ability of departments to plan with the require d accuracy. Two further phantoms have been constructed and will be used in the second round of audit visits; one is a water-filled three-dimensional p hantom for investigating off-axis dosimetry, the other is to be used to ass ess dose in the junction region between the tangential fields and the supra clavicular fossa field. The manufacturing and design process for each of th e phantoms is discussed.