Dosimetric comparison of VMAT plans in preoperative short-course rectal radiotherapy.

Recently, neoadjuvant short-course radiation therapy (SCRT) has emerged as a valid treatment option for patients with locally advanced rectal cancer (LARC). We assessed SCRT plans using volumetric-modulated arc therapy (VMAT) with Halcyon and Infinity medical linear accelerators (Linacs) and compared the plan quality and delivery efficiency across all cases. Thirty patients who underwent preoperative SCRT for LARC at the hospital were randomly selected. Treatment plans were designed using the Halcyon and Infinity linac platforms, generating Halcyon VMAT plans (Group H) and Infinity VMAT plans (Group I). The target coverage, organ at risk (OAR) dose distribution, number of monitor units, treatment delivery time, and planning complexity of the two groups were compared and analyzed. Plan quality assurance was performed on the ArcCheck phantom. The overall plan quality regarding target volume and OARs was comparable for plans delivered on Halcyon and Infinity Agility machines, with each platform having advantages. Therefore, both radiotherapy platforms are very good options when selecting which technique to use in the clinic.