Mesane Kanseri İçin Tedavi Planlarının Karşılaştırılması: FIF, YART ve SIB: Dozimetrik Bir Çalışma

Öz

Amaç: Bu çalışmanın amacı, alan içi alan (FIF), yoğunluk ayarlı radyoterapi (YART) ve eşzamanlı entegre boost (SIB) tekniği kullanılarak mesane kanseri için yapılan planları karşılaştırmaktır. 
Yöntem: Mesane kanseri tanısı almış 20 hastanın tomografi görüntüleri kullanılarak FIF, YART ve SIB tedavi planları oluşturuldu. Her hasta için iki ayrı planlama hedef hacmi (PTV) tanımlandı: PTV1 ve PTV2. FIF ve YART planları için, PTV1 ve PTV2'ye sırasıyla 33 fraksiyonda 50,4 Gray (Gy) ve 60 Gy tedavi dozları verildi. 28 günlük fraksiyonda hedef hacimlerde farklı dozların eş zamanlı olarak verildiği SIB yöntemi kullanıldı. SIB tekniğinde günlük tedavi dozu 2,14 Gy olarak belirlendi. Planlar PTV, rektum, bağırsak, femur başları gibi kritik organlar, homojenlik indeksi (HI), konformite indeksi (HI) ve monitör unit değerleri (MU) açısından karşılaştırıldı.
Bulgular: Tüm planlar, hedef hacimdeki dozun %95'ini kapsayacak şekilde tasarlandı. SIB planlarının CI’si FIF ve YART planlarına kıyasla anlamlı derecede daha iyi sonuçlar gösterdi. SIB planlarında rektum için V45 ve V30 dozları, FIF planlarına kıyasla istatistiksel olarak anlamlı derecede daha düşüktü (p<0,05). Rektum V30 BED değerleri, SIB planlarında 57,01±11,94 ve YART planlarında 56,37±10,95 olarak bulundu. MU sayıları, FIF planlarında anlamlı derecede düşüktü (p<0,05).
Sonuç: SIB tekniği, mesane radyoterapisinde FIF ve YART tekniklerine kıyasla kritik organları daha iyi korumuştur. Ancak BED analizi, SIB ile daha yüksek dozlara işaret etmektedir. Genel olarak, kritik organlara verilen dozun dikkatlice izlenmesi koşuluyla, SIB uygun hastalar için uygulanabilir bir seçenek gibi görünmektedir.

Anahtar Kelimeler

• Mesane kanseri
• radyoterapi
• eş zamanlı integral boost

Comparing Treatment Plans for Bladder Cancer: FIF, IMRT and SIB: A Dosimetric Study

Abstract

Aim: The purpose of this study is to compare plans for bladder cancer using field-in-field (FIF), intensity modulated radiotherapy (IMRT) and simultaneous integrated boost (SIB) technique.
Method: FIF, IMRT and SIB treatment plans were created using tomography images of 20 patients diagnosed with bladder cancer. Two separate planning target volume (PTV) were defined for each patient: PTV1 and PTV2. For the FIF and IMRT plans, PTV1 and PTV2 received treatment doses of 50.4 Gray (Gy) and 60 Gy in 33 fractions, respectively. In 28 daily fractions, the SIB method was used in which different doses were delivered simultaneously in the target volumes. In the SIB technique, the daily treatment dose was determined as 2.14 Gy. The plans were compared in terms of PTV, organs at risk (OARs) such as rectum, bowel, femoral heads, homogeneity index (HI), conformity index (CI) and monitor unit values (MU).
Results: All plans were designed to cover 95% of the dose in the target volume. The CI for SIB plans showed significantly favourable results compared to FIF and IMRT plans. The V45 and V30 doses for the rectum in the SIB plans were statistically significantly lower compared to the FIF (p<0.05). The biologically effective doses (BED) values of rectum V30 were found to be 57.01±11.94 in SIB plans and 56.37±10.95 in IMRT plans. MU counts were significantly lower in FIF plans (p<0.05).
Conclusion: The SIB technique demonstrated better sparing of critical organs compared with FIF and IMRT in bladder radiotherapy. BED analysis, however, indicated higher doses with SIB. Overall, SIB appears to be a feasible option for appropriate patients, provided that dose to critical organs is carefully monitored.

Keywords

• Bladder cancer
• radiotherapy
• simultaneous integrated boost

Kaynakça

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