SU‐D‐105‐02: Small Field SRS/SBRT Patient Specific QA at Extended SSD

Sotirios Stathakis, P. Mavroidis, C. Esquivel, P. Myers, Ying Li, Richard L Crownover, Nikos Papanikolaou

Research output: Contribution to journalArticle

Abstract

Purpose: To determine if intensity optimized beams for SBRT can be accurately measured using a commercially available 2D detector array at extended SSD in order to increase the area of the detector exposed at any given time. Materials and Methods: Five patients (n=5) with forty five (n=45) fields have been analyzed in this study. The plans were optimized for the following clinical sites: two liver, two lung and one spine. The detector array used for the measurements is the PTW Seven29 array. All plans have been optimized and calculated using Eclipse v8.9. The center of the array was setup 215cm from the source and all fields were measured and analyzed one by one. All measurements were performed on a NovalisTX linear accelerator equipped with high definition multileaf collimator. The evaluation was based mainly on gamma index passing rates using 2mm DTA and 2%. Results: The accuracy of the Eclipse TPS at extended SSDs using an ionization chamber was measured to be within 1.5%. All field measurements were performed and analyzed individually. The percent of the points that had a gamma index of less than 1 using 3%/3mm was >98% for all measurements. In order to better evaluate our process and distinguish smaller differences a new set of gamma index tolerances of 2%/2mm. In this case, the gamma index passing rates ranged from 90.8 to 100% (95.5%+/−3%). The profile comparison showed that the detector array measurements followed closely the calculated profiles, even for fields optimized with multiple peaks and valleys. Conclusion: The PTW Seven29 detector can be successfully used for SBRT patient specific QA when small fields are used by increasing the distance to approximately 200cm from the source. Very good agreement between measured and calculated planar doses was achieved using this setup geometry.

Original languageEnglish (US)
Pages (from-to)100
Number of pages1
JournalMedical Physics
Volume40
Issue number6
DOIs
StatePublished - 2013

Fingerprint

Silver Sulfadiazine
Particle Accelerators
Spine
Lung
Liver

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

Cite this

Stathakis, S., Mavroidis, P., Esquivel, C., Myers, P., Li, Y., Crownover, R. L., & Papanikolaou, N. (2013). SU‐D‐105‐02: Small Field SRS/SBRT Patient Specific QA at Extended SSD. Medical Physics, 40(6), 100. https://doi.org/10.1118/1.4813998

SU‐D‐105‐02 : Small Field SRS/SBRT Patient Specific QA at Extended SSD. / Stathakis, Sotirios; Mavroidis, P.; Esquivel, C.; Myers, P.; Li, Ying; Crownover, Richard L; Papanikolaou, Nikos.

In: Medical Physics, Vol. 40, No. 6, 2013, p. 100.

Research output: Contribution to journalArticle

Stathakis, S, Mavroidis, P, Esquivel, C, Myers, P, Li, Y, Crownover, RL & Papanikolaou, N 2013, 'SU‐D‐105‐02: Small Field SRS/SBRT Patient Specific QA at Extended SSD', Medical Physics, vol. 40, no. 6, pp. 100. https://doi.org/10.1118/1.4813998
Stathakis S, Mavroidis P, Esquivel C, Myers P, Li Y, Crownover RL et al. SU‐D‐105‐02: Small Field SRS/SBRT Patient Specific QA at Extended SSD. Medical Physics. 2013;40(6):100. https://doi.org/10.1118/1.4813998
Stathakis, Sotirios ; Mavroidis, P. ; Esquivel, C. ; Myers, P. ; Li, Ying ; Crownover, Richard L ; Papanikolaou, Nikos. / SU‐D‐105‐02 : Small Field SRS/SBRT Patient Specific QA at Extended SSD. In: Medical Physics. 2013 ; Vol. 40, No. 6. pp. 100.
@article{872cee775248464894ea80211f522f92,
title = "SU‐D‐105‐02: Small Field SRS/SBRT Patient Specific QA at Extended SSD",
abstract = "Purpose: To determine if intensity optimized beams for SBRT can be accurately measured using a commercially available 2D detector array at extended SSD in order to increase the area of the detector exposed at any given time. Materials and Methods: Five patients (n=5) with forty five (n=45) fields have been analyzed in this study. The plans were optimized for the following clinical sites: two liver, two lung and one spine. The detector array used for the measurements is the PTW Seven29 array. All plans have been optimized and calculated using Eclipse v8.9. The center of the array was setup 215cm from the source and all fields were measured and analyzed one by one. All measurements were performed on a NovalisTX linear accelerator equipped with high definition multileaf collimator. The evaluation was based mainly on gamma index passing rates using 2mm DTA and 2{\%}. Results: The accuracy of the Eclipse TPS at extended SSDs using an ionization chamber was measured to be within 1.5{\%}. All field measurements were performed and analyzed individually. The percent of the points that had a gamma index of less than 1 using 3{\%}/3mm was >98{\%} for all measurements. In order to better evaluate our process and distinguish smaller differences a new set of gamma index tolerances of 2{\%}/2mm. In this case, the gamma index passing rates ranged from 90.8 to 100{\%} (95.5{\%}+/−3{\%}). The profile comparison showed that the detector array measurements followed closely the calculated profiles, even for fields optimized with multiple peaks and valleys. Conclusion: The PTW Seven29 detector can be successfully used for SBRT patient specific QA when small fields are used by increasing the distance to approximately 200cm from the source. Very good agreement between measured and calculated planar doses was achieved using this setup geometry.",
author = "Sotirios Stathakis and P. Mavroidis and C. Esquivel and P. Myers and Ying Li and Crownover, {Richard L} and Nikos Papanikolaou",
year = "2013",
doi = "10.1118/1.4813998",
language = "English (US)",
volume = "40",
pages = "100",
journal = "Medical Physics",
issn = "0094-2405",
publisher = "AAPM - American Association of Physicists in Medicine",
number = "6",

}

TY - JOUR

T1 - SU‐D‐105‐02

T2 - Small Field SRS/SBRT Patient Specific QA at Extended SSD

AU - Stathakis, Sotirios

AU - Mavroidis, P.

AU - Esquivel, C.

AU - Myers, P.

AU - Li, Ying

AU - Crownover, Richard L

AU - Papanikolaou, Nikos

PY - 2013

Y1 - 2013

N2 - Purpose: To determine if intensity optimized beams for SBRT can be accurately measured using a commercially available 2D detector array at extended SSD in order to increase the area of the detector exposed at any given time. Materials and Methods: Five patients (n=5) with forty five (n=45) fields have been analyzed in this study. The plans were optimized for the following clinical sites: two liver, two lung and one spine. The detector array used for the measurements is the PTW Seven29 array. All plans have been optimized and calculated using Eclipse v8.9. The center of the array was setup 215cm from the source and all fields were measured and analyzed one by one. All measurements were performed on a NovalisTX linear accelerator equipped with high definition multileaf collimator. The evaluation was based mainly on gamma index passing rates using 2mm DTA and 2%. Results: The accuracy of the Eclipse TPS at extended SSDs using an ionization chamber was measured to be within 1.5%. All field measurements were performed and analyzed individually. The percent of the points that had a gamma index of less than 1 using 3%/3mm was >98% for all measurements. In order to better evaluate our process and distinguish smaller differences a new set of gamma index tolerances of 2%/2mm. In this case, the gamma index passing rates ranged from 90.8 to 100% (95.5%+/−3%). The profile comparison showed that the detector array measurements followed closely the calculated profiles, even for fields optimized with multiple peaks and valleys. Conclusion: The PTW Seven29 detector can be successfully used for SBRT patient specific QA when small fields are used by increasing the distance to approximately 200cm from the source. Very good agreement between measured and calculated planar doses was achieved using this setup geometry.

AB - Purpose: To determine if intensity optimized beams for SBRT can be accurately measured using a commercially available 2D detector array at extended SSD in order to increase the area of the detector exposed at any given time. Materials and Methods: Five patients (n=5) with forty five (n=45) fields have been analyzed in this study. The plans were optimized for the following clinical sites: two liver, two lung and one spine. The detector array used for the measurements is the PTW Seven29 array. All plans have been optimized and calculated using Eclipse v8.9. The center of the array was setup 215cm from the source and all fields were measured and analyzed one by one. All measurements were performed on a NovalisTX linear accelerator equipped with high definition multileaf collimator. The evaluation was based mainly on gamma index passing rates using 2mm DTA and 2%. Results: The accuracy of the Eclipse TPS at extended SSDs using an ionization chamber was measured to be within 1.5%. All field measurements were performed and analyzed individually. The percent of the points that had a gamma index of less than 1 using 3%/3mm was >98% for all measurements. In order to better evaluate our process and distinguish smaller differences a new set of gamma index tolerances of 2%/2mm. In this case, the gamma index passing rates ranged from 90.8 to 100% (95.5%+/−3%). The profile comparison showed that the detector array measurements followed closely the calculated profiles, even for fields optimized with multiple peaks and valleys. Conclusion: The PTW Seven29 detector can be successfully used for SBRT patient specific QA when small fields are used by increasing the distance to approximately 200cm from the source. Very good agreement between measured and calculated planar doses was achieved using this setup geometry.

UR - http://www.scopus.com/inward/record.url?scp=85024826860&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85024826860&partnerID=8YFLogxK

U2 - 10.1118/1.4813998

DO - 10.1118/1.4813998

M3 - Article

AN - SCOPUS:85024826860

VL - 40

SP - 100

JO - Medical Physics

JF - Medical Physics

SN - 0094-2405

IS - 6

ER -