TY - JOUR

T1 - DMLC motion tracking of moving targets for intensity modulated arc therapy treatment

T2 - a feasibility study

AU - Zimmerman, Jens

AU - Korreman, Stine

AU - Persson, Gitte

AU - Cattell, Herb

AU - Svatos, Michelle

AU - Sawant, Amit

AU - Venkat, Raghu

AU - Carlson, David

AU - Keall, Paul

PY - 2009

Y1 - 2009

N2 - PURPOSE: Intensity modulated arc therapy offers great advantages with the capability of delivering a fast and highly conformal treatment. However, moving targets represent a major challenge. By monitoring a moving target it is possible to make the beam follow the motion, shaped by a Dynamic MLC (DMLC). The aim of this work was to evaluate the dose delivered to moving targets using the RapidArc (Varian Medical Systems, Inc.) technology with and without a DMLC tracking algorithm.MATERIAL AND METHODS: A Varian Clinac iX was equipped with a preclinical RapidArc and a 3D DMLC tracking application. A motion platform was placed on the couch, with the detectors on top: a PTW seven29 and a Scandidos Delta4. One lung plan and one prostate plan were delivered. Motion was monitored using a Real-time Position Management (RPM) system. Reference measurements were performed for both plans with both detectors at state (0) "static, no tracking". Comparing measurements were made at state (1) "motion, no tracking" and state (2) "motion, tracking".RESULTS: Gamma analysis showed a significant improvement from measurements of state (1) to measurements of state (2) compared to the state (0) measurements: Lung plan; from 87 to 97% pass. Prostate plan; from 81 to 88% pass. Sub-beam information gave a much reduced pattern of periodically spatial deviating dose points for state (2) than for state (1). Iso-dose curve comparisons showed a slightly better agreement between state (0) and state (2) than between state (0) and state (1).CONCLUSIONS: DMLC tracking together with RapidArc make a feasible combination and is capable of improving the dose distribution delivered to a moving target. It seems to be of importance to minimize noise influencing the tracking, to gain the full benefit from the application.

AB - PURPOSE: Intensity modulated arc therapy offers great advantages with the capability of delivering a fast and highly conformal treatment. However, moving targets represent a major challenge. By monitoring a moving target it is possible to make the beam follow the motion, shaped by a Dynamic MLC (DMLC). The aim of this work was to evaluate the dose delivered to moving targets using the RapidArc (Varian Medical Systems, Inc.) technology with and without a DMLC tracking algorithm.MATERIAL AND METHODS: A Varian Clinac iX was equipped with a preclinical RapidArc and a 3D DMLC tracking application. A motion platform was placed on the couch, with the detectors on top: a PTW seven29 and a Scandidos Delta4. One lung plan and one prostate plan were delivered. Motion was monitored using a Real-time Position Management (RPM) system. Reference measurements were performed for both plans with both detectors at state (0) "static, no tracking". Comparing measurements were made at state (1) "motion, no tracking" and state (2) "motion, tracking".RESULTS: Gamma analysis showed a significant improvement from measurements of state (1) to measurements of state (2) compared to the state (0) measurements: Lung plan; from 87 to 97% pass. Prostate plan; from 81 to 88% pass. Sub-beam information gave a much reduced pattern of periodically spatial deviating dose points for state (2) than for state (1). Iso-dose curve comparisons showed a slightly better agreement between state (0) and state (2) than between state (0) and state (1).CONCLUSIONS: DMLC tracking together with RapidArc make a feasible combination and is capable of improving the dose distribution delivered to a moving target. It seems to be of importance to minimize noise influencing the tracking, to gain the full benefit from the application.

KW - Algorithms

KW - Feasibility Studies

KW - Humans

KW - Lung Neoplasms/radiotherapy

KW - Male

KW - Movement/physiology

KW - Particle Accelerators

KW - Phantoms, Imaging

KW - Prostatic Neoplasms/radiotherapy

KW - Radiotherapy Dosage

KW - Radiotherapy, Intensity-Modulated/instrumentation

KW - Respiration

KW - Scattering, Radiation

U2 - 10.1080/02841860802266722

DO - 10.1080/02841860802266722

M3 - Journal article

C2 - 18720056

VL - 48

SP - 245

EP - 250

JO - Acta Oncologica

JF - Acta Oncologica

SN - 1100-1704

IS - 2

ER -