Dosage along the matchline between upper head-and-neck IMRT fields and conventional supraclavicular fields

There is concern about dose along the matchline when upper head-and-neck fields are treated with IMRT and the lower (supraclavicular) field is treated with a conventional fixed beam. An anatomical phantom was scanned and planned with IMRT upper head-and-neck fields and a fixed-beam supraclavicular field. The plans were fused and dose was calculated to points along the matchline. These doses were compared with thermolaminescent dosimetry measurements in the phantom, as the phantom was treated according to the plans.