Optimal Patient Selection for Stereotactic Body Radiation Therapy: A Practical Approach in a High-Volume Community-Based Private Setting

Abstract

Establishment of an objective and documentable selection process of patients for free-breathing stereotactic body radiation therapy (SBRT) in a high-volume community-based private setting. A vendor-based respiratory gating system and wide-bore multi-slice CT simulation acquire 4-dimensional image data sets throughout full respiratory cycles. SBRT is delivered on modern linear accelerators including SBRT-dedicated systems, with respiratory gating control and multiple volumetric modulated arc therapy (VMAT) techniques. Flattening Filter Free (FFF) mode of RT delivery is available as needed. Use of cone-beam CT image guidance and 6 degrees of freedom patient repositioning are also available to optimize target alignment. Patients were observed closely at time of CT simulation to select those with optimal and stable respiratory patterns with or without the need for supplemental oxygen. Selection of appropriate patients for SBRT is needed to assure optimal CT simulation image capture, prediction for subsequent treatment deliverability, and reproducibility of high dose SBRT. Typical SBRT is up to 10 Gy per fraction for 5 fractions. Through real-time evaluation of respiratory patterns, appropriate patients can be selected for SBRT. Compliance rate of selected patients during simulation and subsequent SBRT is 100% without significant interruption during SBRT delivery. Use of respiratory gating control effectively prevents out-of-range SBRT delivery during fits of coughing and dyspnea. Use of FFF mode and VMAT via multiple arcs significantly reduces SBRT delivery time and optimizes normal tissue protection. The selection ”process“ is also recorded via screen capture of the respiratory cycles with a corresponding graphical representation of steady breathing patterns. These graphics can then be inserted into the CT simulation documentation as part of the permanent electronic health record. Appropriate selection of patients for SBRT via objective analysis and recorded respiratory patterns ensures optimal conditions for clinical setup, tumor targeting, and reproducible delivery of SBRT. This process is also recorded in the electronic health records of each patient for permanent documentation, future reference, and chart review.