Motorize kama ile alan-içi-alan tekniklerinin yüksek enerjili x-ışını demetlerindeki davranışlarının dozimetrik karşılaştırılması
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Dosyalar
Tarih
2014
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Yayıncı
Hatay Mustafa Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Radyoterapide reçetelendirilen dozu hedef hacme yüksek hassasiyetle vermek büyük önem taşımaktadır. Tümöre maksimum dozu verirken, yanındaki sağlam dokularda dozu minimuma indirmek çok önemlidir. Alan dışı dozlar, kritik organ dozları gibi durumlarda yaşam kalitesinin yüksekliği ve ikincil kanser riski açısından çok önemlidir. Bu amaçla kliniğimizde kullandığımız XIO tedavi planlama sisteminde (TPS) alan içi ve alan dışı dozların karşılaştırılması amaçlandı. Çalışmamızda ölçülen ve hesaplanan dozların karşılaştırılmasında RW3 katı-su fantomu kullanıldı. Tek boyutlu ve iki boyutlu doz ölçümleri, silindirik (farmer) iyon odası ve MatriXX iyon odası sistemleriyle yapıldı. İki farklı enerjide (6, 18MV) hesaplanan doz değerleri ile ölçülen değerler karşılaştırıldı. Hesaplanan doz değerleri ile ölçülen doz değerleri gama analizi metoduyla incelendi. İki farklı dedektör sistemi ile elde edilen alan içi alan dışı doz değerleri TPS'den elde edilen değerlerle karşılaştırıldı. Alan merkezinde planlanan ve ölçülen dozlar arasında yüksek farklar görülmese de FIF (Alan-içi-Alan) daha yakın sonuçlar verdi. Her iki teknikte dozun hızlı değişime uğradığı alan kenarlarında CC04'ün yapısından kaynaklı farklar MatriXX'e göre daha da yüksek çıktı. Kama, FIF'e göre MU (Monitör Unit) değerlerini ciddi şekilde artırdı. Özellikle alan dışı ölçülen dozların hesaplanan dozlardan daha yüksek çıkması, modellemede kamanın ikinci bir kaynak olarak hesaba katılmamasından dolayıdır. Segmentasyon yöntemiyle bu durum giderilebilir. Tedavi planlama sisteminde (TPS) homojen doz dağılımları için kullanılan motorize kama ve alan-içi-alan (FIF) tekniklerinin kalite kontrolleri ve birbirlerine göre üstünlükleri araştırıldı. Uygulanan yöntemlerin sonuçları incelendiğinde FIF tekniğinin daha güvenilir olduğu sonucuna varıldı.
Radiotherapy delivering the prescribed dose to the target volume accurately has a great importance. While giving the maximum dose to the tumor, it is very important to minimize the dose around the health tissues. Out of field doses is very important in cases such as critical organ doses in terms of the quality of high life standard and secondary cancer risk. In XIO treatment planning system (TPS) that we use in our clinic for this purpose, field in and field out doses have been aimed to be compared. In our study, RW3 solid-water phantom (IBA) was used for the comparison of measured and calculated doses. Two detectors were used in the measurements, farmer type ion chamber for one-dimensional and Matrix ion chamber for two-dimensional. Calculated and measured values were compared at two different energies (6 and 18MV). All measurements were founded with two detectors using the same sets. Calculated and measured dose values were analyzed by the analysis method of gamma. All detector readings obtained from two different areas, in-field and out-field, were compared with the values obtained from TPS. Even if there isn't much difference between the planned and measured doses, FIF (Field in Field) gave closer results. In both techniques, when compared with MatriXX, in the edges of the field where the dose has a rapid change, the differences that results (derives) from the structure of CC04 was even much more higher. Kama seriously increased the MU values when compared with FIF. Especially the doses measured out of field are higher than calculated doses and this is because that Kama was not consulted as a second resource in the modelling. This situation can be resolved with segmentation method. In treatment planning system (TPS), the controls of the techniques of motorize wedge used for homogeneous dose distribution and Field-in-Field and their advantages compared to each other were investigated. When the results of the applied methods were researched, it was concluded that FIF technique is more reliable.
Radiotherapy delivering the prescribed dose to the target volume accurately has a great importance. While giving the maximum dose to the tumor, it is very important to minimize the dose around the health tissues. Out of field doses is very important in cases such as critical organ doses in terms of the quality of high life standard and secondary cancer risk. In XIO treatment planning system (TPS) that we use in our clinic for this purpose, field in and field out doses have been aimed to be compared. In our study, RW3 solid-water phantom (IBA) was used for the comparison of measured and calculated doses. Two detectors were used in the measurements, farmer type ion chamber for one-dimensional and Matrix ion chamber for two-dimensional. Calculated and measured values were compared at two different energies (6 and 18MV). All measurements were founded with two detectors using the same sets. Calculated and measured dose values were analyzed by the analysis method of gamma. All detector readings obtained from two different areas, in-field and out-field, were compared with the values obtained from TPS. Even if there isn't much difference between the planned and measured doses, FIF (Field in Field) gave closer results. In both techniques, when compared with MatriXX, in the edges of the field where the dose has a rapid change, the differences that results (derives) from the structure of CC04 was even much more higher. Kama seriously increased the MU values when compared with FIF. Especially the doses measured out of field are higher than calculated doses and this is because that Kama was not consulted as a second resource in the modelling. This situation can be resolved with segmentation method. In treatment planning system (TPS), the controls of the techniques of motorize wedge used for homogeneous dose distribution and Field-in-Field and their advantages compared to each other were investigated. When the results of the applied methods were researched, it was concluded that FIF technique is more reliable.
Açıklama
Anahtar Kelimeler
Fizik ve Fizik Mühendisliği, Physics and Physics Engineering
