Analysis of patient repositioning accuracy in precision radiation therapy using automated image fusion

James L Robar,Chang Seon Kim,Brenda G Clark,Jason W Schella

doi:10.1120/jacmp.2023.25323

Abstract

Analysis of patient repositioning accuracy in precision radiation therapy using automated image fusion

Highlights

Fractionated stereotactic radiotherapy (SRT) is a widely-used treatment technique requiring stringent control over the spatial accuracy of the radiation dose delivered
The accuracy of inter-fractional patient repositioning has been investigated for various immobilization systems by acquiring sequential orthogonal radiographs or portal images.[1,2,3,4,5,6,7,8,9,10,11,12] This approach usually involves the acquisition of anterior-posterior and lateral projection radiographs of the patient anatomy, determination of locations of anatomical landmarks in relation to a fixed reference point, and subsequent comparison of these locations to those from reference images
If rigid immobilization is used, the magnitude of actual repositioning errors may be on the order of 3 mm or less[3,9,13,14,15]; the uncertainty in the observation may represent a significant proportion of the error itself.[15]. Another shortcoming of this approach is that the location of the gross tumor volume itself is not observed directly, and shifts of the target volume are determined only in relation to clearlyvisualized structures,(3,6,8,9,12) such as bony anatomy

Summary

Introduction

Fractionated stereotactic radiotherapy (SRT) is a widely-used treatment technique requiring stringent control over the spatial accuracy of the radiation dose delivered. The accuracy of inter-fractional patient repositioning has been investigated for various immobilization systems by acquiring sequential orthogonal radiographs or portal images.[1,2,3,4,5,6,7,8,9,10,11,12] This approach usually involves the acquisition of anterior-posterior and lateral projection radiographs of the patient anatomy, determination of locations of anatomical landmarks in relation to a fixed reference point (e.g., in the stereotactic coordinate system), and subsequent comparison of these locations to those from reference images Another shortcoming of this approach is that the location of the gross tumor volume itself is not observed directly, and shifts of the target volume are determined only in relation to clearlyvisualized structures,(3,6,8,9,12) such as bony anatomy

Methods

Results

Discussion

Conclusion