TY - JOUR
T1 - Treatment planning evaluation of sliding window and multiple static segments technique in intensity modulated radiotherapy
AU - Iqbal, Khalid
AU - Isa, Muhammad
AU - Buzdar, Saeed Ahmad
AU - Gifford, Kent Aallen
AU - Afzal, Muhammad
PY - 2013/3
Y1 - 2013/3
N2 - Background: The demand of improved dose conformity of the tumor has been increased in radiation therapy with the advent of recent imaging facilities and efficient computer technologies. Aim: We compared the intensity modulated radiotherapy (IMRT) plans delivered with the sliding window (SW IMRT) and step and shoot (SS IMRT) techniques. Materials and methods: Thirteen patients were planned on 15 MV X-ray for five, seven, nine and thirteen beams direction making the dose constraints analogous. Eclipse treatment planning system with Helios inverse planning software, and Linear Accelerator Varian 2100C/D with 120 multileaf collimators (MLCs) were used. Gamma analysis was applied to the data acquired with the MapCheck 2™ for different beam directions plan in the sliding window and step and shoot technique to meet the 95% pass criteria at 3%/3mm. The plans were scrutinized using Dmean, Dmax, D1%, D95%, dose uniformity index (UI), dose conformity index (CI), dose homogeneity index (HI) and monitor units (MUs). Results: Our data show comparable coverage of the planning target volume (PTV) for both the sliding window and step and shoot techniques. The volume of PTV receiving the prescription dose was 99.8. ± 0.05% and the volume of PTV receiving the maximum dose was 107.6. ± 2.5% in both techniques. Bladder and rectum maximum mean doses for the sliding window and step and shoot plans were 38.1. ± 2.6% and 42.9. ± 10.7%. Homogeneity index (HI) for both techniques was 0.12. ± 0.02 and 0.13. ± 0.02, uniformity index (UI) was 1.07. ± 0.02 and 108. ± 0.01 and conformity index at 98% isodose (CI 98%) was 0.96. ± 0.005 and 0.96. ± 0.005 for the sliding window and step and shoot techniques, respectively, and MUs were 10. ± 12% lower in the step and shoot compared to the sliding window technique. Conclusion: All these factors indicate that coverage for PTV was nearly identical but dose to organs-at-risk (OARs) was lower in the step and shoot technique.
AB - Background: The demand of improved dose conformity of the tumor has been increased in radiation therapy with the advent of recent imaging facilities and efficient computer technologies. Aim: We compared the intensity modulated radiotherapy (IMRT) plans delivered with the sliding window (SW IMRT) and step and shoot (SS IMRT) techniques. Materials and methods: Thirteen patients were planned on 15 MV X-ray for five, seven, nine and thirteen beams direction making the dose constraints analogous. Eclipse treatment planning system with Helios inverse planning software, and Linear Accelerator Varian 2100C/D with 120 multileaf collimators (MLCs) were used. Gamma analysis was applied to the data acquired with the MapCheck 2™ for different beam directions plan in the sliding window and step and shoot technique to meet the 95% pass criteria at 3%/3mm. The plans were scrutinized using Dmean, Dmax, D1%, D95%, dose uniformity index (UI), dose conformity index (CI), dose homogeneity index (HI) and monitor units (MUs). Results: Our data show comparable coverage of the planning target volume (PTV) for both the sliding window and step and shoot techniques. The volume of PTV receiving the prescription dose was 99.8. ± 0.05% and the volume of PTV receiving the maximum dose was 107.6. ± 2.5% in both techniques. Bladder and rectum maximum mean doses for the sliding window and step and shoot plans were 38.1. ± 2.6% and 42.9. ± 10.7%. Homogeneity index (HI) for both techniques was 0.12. ± 0.02 and 0.13. ± 0.02, uniformity index (UI) was 1.07. ± 0.02 and 108. ± 0.01 and conformity index at 98% isodose (CI 98%) was 0.96. ± 0.005 and 0.96. ± 0.005 for the sliding window and step and shoot techniques, respectively, and MUs were 10. ± 12% lower in the step and shoot compared to the sliding window technique. Conclusion: All these factors indicate that coverage for PTV was nearly identical but dose to organs-at-risk (OARs) was lower in the step and shoot technique.
KW - Conformity index
KW - Homogeneity index
KW - Intensity modulated radiation therapy
KW - Organs-at-risk
KW - Uniformity index
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U2 - 10.1016/j.rpor.2012.10.003
DO - 10.1016/j.rpor.2012.10.003
M3 - Article
C2 - 24416536
AN - SCOPUS:84875628257
SN - 1507-1367
VL - 18
SP - 101
EP - 106
JO - Reports of Practical Oncology and Radiotherapy
JF - Reports of Practical Oncology and Radiotherapy
IS - 2
ER -