Prog Med Phys.  2015 Dec;26(4):223-228. 10.14316/pmp.2015.26.4.223.

Evaluation of Dosimetric Characteristics of a Double-focused Dynamic Micro-Multileaf Collimator (DMLC)

• Kim AR
• Seo JH
• Shin HJ
• Park HW
• Lee KW
• Lee JC
• Kim SW
• Kim JN
• Park H
• Lee HK
• Kang YN

• KMID: 2151755
• DOI: http://doi.org/10.14316/pmp.2015.26.4.223

Abstract

Double-focused micro-Multileaf Collimator (microMLC) is able to create radiation fields having sharper dose gradients at the field edges than common MLC. Therefore, microMLC has been used for the stereotactic radio-surgery (SRS) and Stereotactic Radiotherapy (SRT). We evaluated the dosimetric characteristics of a double-focused Dynamic-microMLC (DMLC) attached to the Elekta Synergy linear accelerator. For this study, the dosimetric parameters including, Percent Depth Dose (PDD), Leaf leakage and penumbra, have been measured by using of the radiochromic films (GafChromic EBT2), EDGE diode detector and three-dimensional water phantom. All datas were measured on 6 MV x-ray. As a result, The DMLC shows transmission below to 1% and because of double-focused construction of the DMLC, the penumbras of fields with DMLC are independent from the field sizes. In this paper, the resulting dosimetric evaluations proved the applicability of the DMLC attached to the Elekta Synergy linear accelerator.

Keyword

Dynamic micro-Multileaf Collimator; PDD; Leaf transmission; Penumbra

MeSH Terms

Particle Accelerators
Radiotherapy
Water
Water

Figure

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  Fig. 1. Dynamic micro-multileaf collimator (DMLC) attached to the Elekta Synergy linear accelerator. The electrical connection between the DMLC and the gantry is established by only on cable.

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  Fig. 2. (a) Scheme of the transverse view of the DMLC. (b) Detail of the leaves of the DMLC. All distance are in mm.

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  Fig. 3. Percent depth dose of (a) field size 6×6 cm2, (b) 3.6×3.6 cm2 for 6 MV.

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  Fig. 4. In-plane profile about interleaf leakage and intra-leaf transmission. The field closed at isocenter.

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  Fig. 5. Cross-plane profile about abutted leaf setup field. The position of 5 peaks shown the abutted leaf position.

Reference

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