The Dosimetric Comparison of the Different Photon Energy of Radiotherapy Techniques Used in the Treatment of Cervical Cancer

Abstract

In this study, it was evaluated retrospectively the result of  10 patients with cervical cancer who treated with radiotherapy treatment in Bursa Uludağ University between 2014-2017 years. Four different plans were performed using 6 MV and 15 MV photon energies both for volumetric modulated arc therapy (VMAT) and intensity modulated arc therapy (IMRT) 7 field technique used in the treatment planning. All patient were to receive  50.4 Gy dose from 28 fractions. Our aim to organ at risks(OAR) such as; the rectal, bladder, small intestine, right and left femoral heads also Conformity Index(CI) and Homogeneity Index(HI) and total numbers of monitor units  were evaluated. As a result of the comparison, the optimal PTV dose homogeneity, the CI value was better in VMAT 15 MV plans and IMRT 15 MV plans showed the best HI values. Bladder and rectum doses were obtained in VMAT 6 MV technique,small intestine doses in IMRT 15 MV technique. Regarding to all planning techniques, dose distributions were within acceptable limits. VMAT 6 MV technique is superior to other techniques when considering the scattered dose and the risk of secondary cancer. Therefore, considering side effects and double effect, VMAT may be preferred as a treatment technique.

Keywords

• Cervix Cancer,Radyoterapy,VMAT,IMRT,Low and High Energy

Serviks Kanseri Tedavisinde Kullanılan Radyoterapi Tekniklerinin Farklı Foton Enerjilerinin Dosimetrik Karşılaştırılması

Abstract

Bu çalışma 2014-2017 yılları arasında Bursa Uludağ Üniversitesinde radyoterapi tedavisi almış,  serviks kanseri tanılı 10 hastanın arşiv materyali kullanılarak retrospektif olarak yapılmıştır. Serviks kanseri radyoterapisinde kullanılan enerji seviyelerinin kullanılması amaçlanmıştır. Tedavi planlamasında kullanılan volumetrik ayarlı ark terapi (VMAT) ve yoğunluk ayarlı ark terapi(YART) 7 alan tekniği için 6 MV  ve  15 MV  enerjili foton enerjisi kullanılarak her hastaya özel 4 farklı planlama yapılmıştır. Planlanan hedef hacme 28 fraksiyondan 50.4 Gy doz verilmiş ve kritik organ olarak rektum, mesane, ince bağırsak, sağ ve sol femur başları konturlanarak dozimetrik karşılaştırma amaçlanmıştır. Ayrıca tedavi planı değerlendirme parametrelerinden Conformite İndeksi ve Homojenite İndeksi verileri de değerlendirilmiştir. Karşılaştırmalar sonucunda en uygun PTV doz homojenitesi, CI değerini VMAT 15 MV, en iyi HI değerini YART 15 MV sağlamıştır. Mesane ve Rectum D_ort  dozları açısından en iyi VMAT 6 MV tekniği, ince bağırsak D_max değeri YART 15 MV tekniğinde elde edilmiştir. Tüm tekniklerde doz dağılımları kabul edilebilir sınır içerisinde olduğu gözlemlenmiştir Saçılan doz ve ikincil kanser riski düşünüldüğünde VMAT 6 MV tekniği diğer tekniklere oranla daha üstün bulundu. Bu yüzden yan etkiler ve çift oluşum meydana gelme ihtimali göz önüne alındığında tedavi tekniği olarak VMAT 6 MV tekniğinin uygun olduğunu desteklemekteyiz.

Keywords

• Serviks kanser,Radyoterapi,VMAT,YART,Düşük ve Yüksek Enerji

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