TY - JOUR
T1 - The implication of non-cyclic intrafractional longitudinal motion in SBRT by TomoTherapy
AU - Yang, Wensha
AU - Van Ausdal, Ray
AU - Read, Paul
AU - Larner, James
AU - Benedict, Stanley H
AU - Sheng, Ke
PY - 2009
Y1 - 2009
N2 - To determine the dosimetric impact of non-cyclic longitudinal intrafractional motion, TomoTherapy plans with different field sizes were interrupted during a phantom delivery, and a displacement between -5 mm and 5 mm was induced prior to the delivery of the completion procedure. The planar dose was measured by film and a cylindrical phantom, and under-dosed or over-dosed volume was observed for either positive or negative displacement. For a 2.5 cm field, there was a 4% deviation for every mm of motion and for a 1 cm field, the deviation was 8% per mm. The dimension of the under/over-dosed area was independent of the motion but dependent on the field size. The results have significant implication in small-field high-dose treatments (i.e. stereotactic body radiation therapy (SBRT)) that deliver doses in only a few fractions. Our studies demonstrate that a small longitudinal motion may cause a dose error that is difficult to compensate; however, dividing a SBRT fraction into smaller passes is helpful to reduce such adverse effects.
AB - To determine the dosimetric impact of non-cyclic longitudinal intrafractional motion, TomoTherapy plans with different field sizes were interrupted during a phantom delivery, and a displacement between -5 mm and 5 mm was induced prior to the delivery of the completion procedure. The planar dose was measured by film and a cylindrical phantom, and under-dosed or over-dosed volume was observed for either positive or negative displacement. For a 2.5 cm field, there was a 4% deviation for every mm of motion and for a 1 cm field, the deviation was 8% per mm. The dimension of the under/over-dosed area was independent of the motion but dependent on the field size. The results have significant implication in small-field high-dose treatments (i.e. stereotactic body radiation therapy (SBRT)) that deliver doses in only a few fractions. Our studies demonstrate that a small longitudinal motion may cause a dose error that is difficult to compensate; however, dividing a SBRT fraction into smaller passes is helpful to reduce such adverse effects.
UR - http://www.scopus.com/inward/record.url?scp=67649891094&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=67649891094&partnerID=8YFLogxK
U2 - 10.1088/0031-9155/54/9/019
DO - 10.1088/0031-9155/54/9/019
M3 - Article
C2 - 19384001
AN - SCOPUS:67649891094
VL - 54
SP - 2875
EP - 2884
JO - Physics in Medicine and Biology
JF - Physics in Medicine and Biology
SN - 0031-9155
IS - 9
ER -