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. 2012 May 19;17(3):157-62.
doi: 10.1016/j.rpor.2012.03.004. eCollection 2012.

Comparison of individual and composite field analysis using array detector for Intensity Modulated Radiotherapy dose verification

Sathiyan Saminathan  1 , Varatharaj Chandraraj  1 , C H Sridhar  2 , Ravikumar Manickam  1
Affiliations

Comparison of individual and composite field analysis using array detector for Intensity Modulated Radiotherapy dose verification

Sathiyan Saminathan et al. Rep Pract Oncol Radiother. .

Abstract

Aim: To compare the measured and calculated individual and composite field planar dose distribution of Intensity Modulated Radiotherapy plans.

Materials and methods: The measurements were performed in Clinac DHX linear accelerator with 6 MV photons using Matrixx device and a solid water phantom. The 20 brain tumor patients were selected for this study. The IMRT plan was carried out for all the patients using Eclipse treatment planning system. The verification plan was produced for every original plan using CT scan of Matrixx embedded in the phantom. Every verification field was measured by the Matrixx. The TPS calculated and measured dose distributions were compared for individual and composite fields.

Results and discussion: The percentage of gamma pixel match for the dose distribution patterns were evaluated using gamma histogram. The gamma pixel match was 95-98% for 41 fields (39%) and 98% for 59 fields (61%) with individual fields. The percentage of gamma pixel match was 95-98% for 5 patients and 98% for other 12 patients with composite fields. Three patients showed a gamma pixel match of less than 95%. The comparison of percentage gamma pixel match for individual and composite fields showed more than 2.5% variation for 6 patients, more than 1% variation for 4 patients, while the remaining 10 patients showed less than 1% variation.

Conclusion: The individual and composite field measurements showed good agreement with TPS calculated dose distribution for the studied patients. The measurement and data analysis for individual fields is a time consuming process, the composite field analysis may be sufficient enough for smaller field dose distribution analysis with array detectors.

Keywords: Gamma pixel; IMRT; I’matriXX; TPS.

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Figures

Fig. 1
Fig. 1
Matrixx along with slap phantom.
Fig. 2
Fig. 2
Comparison of measured and calculated dose distribution for individual field.
Fig. 3
Fig. 3
(a) and (b) Compared profile along the X and Y directions for individual field.
Fig. 4
Fig. 4
Compared isodose distribution for individual field.
Fig. 5
Fig. 5
Comparison of measured and calculated dose distribution for composite field.
Fig. 6
Fig. 6
(a) and (b) Compared profile along the X and Y directions for composite field.
Fig. 7
Fig. 7
Compared isodose distribution for composite field.
Fig. 8
Fig. 8
Comparison of percentage gamma pixel match values for individual and composite fields.
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References

    1. Kallman P., Lind B., Eklof A., Brahme A. Shaping of arbitrary dose distribution by dynamic multileaf collimation. Phys Med Biol. 1998;33:1291–1300. - PubMed
    1. Bayouth J.E., Wendt D., Morrill S.M. MLC quality assurance technique for IMRT applications. Med Phys. 2003;30(5):743–750. - PubMed
    1. Chui C.-S., Spirou S., LoSasso T. Testing of dynamic multileaf collimation. Med Phys. 1996;23(5):635–641. - PubMed
    1. LoSasso T., Chui C.-S., Ling C. Comprehensive quality assurance for the delivery of intensity modulated radiotherapy with a multileaf collimator used in the dynamic mode. Med Phys. 2001;28(11):2209–2219. - PubMed
    1. Gopi S., Ganesan S., Aruna P., Bouchaib R., Supe S.S. Influence of photon beam energy on IMRT plan quality for radiotherapy of prostate cancer. Rep Pract Oncol Radiother. 2009;14(1):18–31.

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