"Integral Dose and Dosimetric Comparison of NeoAdjuvant Simultaneous Integrated Boost (SIB) Radiotherapy Technique for Rectal Cancer Using Intensity-Modulated Radiotherapy (IMRT), Volumetric Modulated Arc Therapy (VMAT), and Helical Tomotherapy (HT)"

Abstract

Abstract:The purpose of the present study is to compare the Intensity-Modulated Radiotherapy (IMRT), Volumetric Modulated Arc Therapy(VMAT), Helical Tomotherapy (HT) techniques in rectal cancer. A total of 10 patients, were randomly selected for this study. Threeseparate plans were made for each patient: IMRT, VMAT and HT. By using the Simultaneous Integrated Boost (SIB) technique, 45 Gyto pelvic lymph nodes, and 50 Gy 25 fractions were prescribed to the rectum and mesorectum. The PTV parameters, Integral dose,Dose Volume Histograms (DVH) and Organ at Risk were evaluated with 3 separate plans. The PTV Dmax, Integral dose was ensuredat the lowest level in HT. The D2 was detected at the lowest level in HT, and at the highest level in D98. Although there was no difference between Homogeneity Indices (HI), Conformity Index (CI) was found to be better in IMRT and VMAT. The total MU and Beamon Time values were found to be high in HT. The bladder, which is one of the risky organs, was provided at the best level in HT, thevolume in the bowel was provided in VMAT at the lowest level with 35 Gy, and the 45 Gy volume was provided in IMRT. The healthytissue volume was 5 Gy and 10 Gy (cc) as the highest in HT, and 20 Gy volume (cc) was high in IMRT. The Mean V10, V20, V30, V40,Dmean values of the pelvic whole bones were higher in HT.

Öz:Bu çalışmanın amacı rektum kanserinde neoadjuvan radyoterapi uygulamasında SIB (Simultaneous Integrated Boost) tekniği kullanarak Yoğunluk Ayarlı Radyoterapi (YART), Volumetrik Modulated Ark Terapi (VMAT) ve Helikal Tomoterapi (HT) yöntemlerinin karşılaştırılmasıdır. Bu çalışma için toplam 10 hasta randomize olarak seçildi. Her hasta için IMRT,VMAT ve HT olmak üzere 3 ayrı plan yapıldı. Simultaneous Integrated Boost (SIB) tekniği kullanılarak pelvik lenf nodlarına 45 Gy; rektum ve mezorektuma 50 Gy 25 fraksiyonda reçetelendirildi. PTV parametreleri, Integral doz, Doz volüm histogramları (DVH) ve risk altındaki organlar 3 ayrı planda değerlendirildi.PTV Dmax, Integral doz en düşük HT’de sağlanmıştır. D2 en az HT’de; D98 en yüksek HT’de bulunmuştur. Homojenite indeksi (HI) arasında fark bulunmazken konformite indeksi (CI) IMRT ve VMAT’da daha iyi bulunmuştur. Toplam MU ve ışınlama süreleri ise HT’de yüksek bulunmuştur. Riskli organlardan mesane en iyi HT’de, bağırsak 35 Gy alan hacim en az VMAT’da 45 Gy alan hacim ise IMRT’de sağlanmıştır. Sağlıklı doku 5 Gy ve 10 Gy alan hacim (cc) en çok HT’de, 20 Gy alan hacim (cc) ise IMRT ‘de yüksek bulunmuştur. Pelvik tüm kemiklerde ortalama V10, V20, V30, V40, Dmean değeri HT ‘de daha yüksek bulunmuştur.