Amaç: Bu çalışmanın amacı, Ege Üniversitesi Tıp Fakültesi Hastanesi veri tabanında bulunan,
merkezi sinir sistemi (MSS) tümörü tanısı ile tedavi edilen 5877 adet olgunun epidemiyolojik ve genel
sağ kalım özelliklerini istatistiksel açıdan değerlendirmek ve literatür ile karşılaştırmaktır.
Gereç ve Yöntem: 1992 ile 2017 yılları arasında Ege Üniversitesi Tıp Fakültesi Hastanesinde tanı
alan 5877 adet MSS kanseri olgusu, Ege Üniversitesi Kanserle Savaş, Uygulama ve Araştırma
Merkezi’nin (EÜKAM) özel eğitimli ve sertifikalı kanser kayıt elemanları tarafından kayıt altına alınan
veriler, Ki-kare testi ve doğrusal modelleme yöntemi kullanılarak analiz edilmiş, p
The aims of the study is to determine the effects of 5 weeks of fractional radiotherapy on silicone elastomer block prostheses in terms of pre-and post-treatment radiotherapy dose distribution and the physical effect of radiation on prostheses. Before starting the radiation dose measurements, a holder was prepared to fix the silicone elastomer block (density 0.917 gr/cm3) in the water phantom at the desired level and was placed inside the water phantom. Using Elekta Linear Accelerator, percent depth dose and dose profile measurements were made for 6 and 10 MV photon beams without silicone prosthesis; gantry 0o, SSD (source-skin distance) 100 cm, field size of 12.5x7.5 cm2 (reference measurement). After that, two prostheses with a total thickness of 3.4 cm were placed on the holder and the depth dose and profiles were measured again with the same SSD and field size. In addition, a container assembly was installed to provide irradiation conditions similar to the measurement setup in the water phantom. For both photon energies, the prostheses were irradiated 5 fractions per week, a total of 25 fractions (50 Gy), according to the monitor unit (MU) times, which corresponds to 2 Gy calculated in the treatment planning system. After irradiation, the prostheses were placed back into the water phantom with the same setup, and the depth doses and profiles were measured again. Pre-irradiation and post-irradiation values were compared. The effect of irradiated and non-irradiated silicon on entrance and exit doses for 6 and 10 MV photon energies was determined and was compared to only water measurements using thermoluminescence dosimetry (TLD). The hardness values of the prostheses were measured by using the Shore A Durometer device. The densities of the irradiated prostheses were recalculated using the Scaltec density determination instrument. The maximum difference caused by non-irradiated prostheses at percent depth doses compared to water was 1.5% for 6 MV and 1.6% for 10 MV. In profile measurements, the maximum dose difference was 2.7% for 6 MV and 2.4% for 10 MV. After irradiation of the prostheses with 25 fractions (50 Gy), the maximum differences were found as 2.5% for 6 MV and 2% for 10 MV. In profile measurements, a dose reduction of 2.6% for 6 MV and 2% for 10 MV was observed. Percent depth dose and profile data before and after irradiation were not found significant. The differences between the percent depth dose and profile data for pre-post irradiation were not significant. There was no important percentage difference between the non-irradiated prostheses and the 50 Gy irradiated prostheses in terms of entrance and exit doses. The percentage difference in exit doses for both energies was higher when both irradiated and non-irradiated prostheses were compared with water. There was no clinical difference between the non-irradiated and irradiated prostheses in terms of hardness and density test results. According to the results of our study, silicone elastomer block prostheses do not occur a clinical difference in terms of radiotherapy dose distribution for 6 and 10 MV photon energies and behave like tissue. In addition, 50 Gy irradiated prosthesis does not create a significant difference in percent depth dose and dose profile compared to the non-irradiated prosthesis. There was a high percentage difference between prostheses and water at exit doses. Standard treatment doses do not cause any physical effects on the prostheses other
