Comparıson of Simultaneous Integrated Boost Method for Different Treatments in Head and Neck Cancer Radiotherapy

Öz

A comparative planning study was undertaken to evaluate dosimetric differences between volumetric modulated arc therapy versus intensity modulated radiation therapy in the treatment of head and neck. Patients were investigated, with a standard prescription of three dose levels to the target volumes in 33 fractions. Simultaneous Integrated Boost technique was generated for all techniques, with similar planning objectives. Plans were calculated for 6MV photon using anisotropic analytical algorithm implemented in Eclipse treatment planning system. 9 field IMRT and 2 arc VMAT plans show superior dose homogeneity and dose conformity in PTVs. Doses to optic nerves, chiasm, eyes, lenses and protists were slightly lower in 7, 9 field IMRT plans. Doses to the brain stem, spinal cord, mandibula and larynx were better in the 2 arc VMAT techniques. Oral cavity dose reduced significantly with 1 arc VMAT. The high dose radiation volume to the normal tissue and the mean normal tissue dose decreased, but the low dose radiation volume increased slightly in the 1 and 2 arc VMAT plans. 1, 2 arc VMAT and 7, 9 field IMRT plans produced clinically acceptable treatment plan for the head and neck cancer. VMAT represents an attractive solution because of the shorter delivery time and the lower of monitor unit compared with IMRT.

Anahtar Kelimeler

• Head and neck cancer,simultaneous integrated boost technique,volumetric modulated arc therapy,intensity modulated radiation therapy

Baş Boyun Radyoterapisinde Farklı Tedavi Teknikleri İle Simultane Integre Boost Yönteminin Karşılaştırılması

Öz

Bu çalışmada, baş boyun kanserlerinin tedavisinde kullanılan yoğunluk ayarlı radyoterapi ve yoğunluk ayarlı ark terapi tekniklerinin dozimetrik olarak karşılaştırılması amaçlanmıştır. Planlarda benzer planlama hedefleri ile 33 günlük fraksiyonlarla eş zamanlı olarak hedef hacimlerde farklı doz seviyelerinin sağlandığı Simultane Integre Boost tekniği kullanılmıştır. Planlar, 6 MV foton enerjisi kullanılarak, anisotropic analitic algoritması ile Eclipse tedavi planlama bilgisayarında hesaplatılmıştır. 9 Alan YART ve 2 Ark YAAT planlarının doz homojenitesi ve doz konformalitesi açısından daha üstün oldukları görülmektedir. Kritik organların doz değerleri incelendiğinde optik sinirler, kiazma, gözler, lensler ve parotisler için en düşük dozlar 7 ve 9 Alan YART planları ile elde edilirken beyin sapı, spinal kord, mandibula ve larenks için en iyi dozlar 2 Ark YAAT planları ile elde edilmiştir. Oral kavite dozu 1 Ark YAAT planları ile önemli ölçüde azaltılabilmektedir. Normal dokuda yüksek doz alan hacim değerleri ve ortalama normal doku doz değerleri 1 ve 2 Ark YAAT planları ile azalırken, normal dokuda düşük doz alan hacim değerleri azda olsa 1 ve 2 Ark planları ile artış göstermektedir. 1, 2 Ark YAAT ve 7, 9 Alan YART planları baş boyun kanserlerinde klinik olarak kabul edilebilir tedavi yöntemleridir. Tedavi süresinin kısalığı ve monitor unit değerlerinin düşük olması açısından YAAT planları daha avantajlıdır.

Anahtar Kelimeler

• Baş boyun kanserleri,simultane integre boost tekniği,yoğunluk ayarlı ark terapi,yoğunluk ayarlı radyoterapi

Kaynakça

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