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Öğe Amelioration of radiation-induced acute inflammation and mucosal atrophy by beta-hydroxy-beta-methylbutyrate, L-glutamine, and L-arginine: results of an experimental study(SPRINGER, 2013) Yavaş, Çağdaş; Yavaş, Güler; Acar, Hilal; Toy, Hatice; Yüce, Deniz; Akyürek, Serap; Ata, ÖzlemWe aimed to evaluate the effects of beta-hydroxy-beta-methylbutyrate, l-glutamine, and l-arginine (HMB/Glu/Arg) on radiation-induced acute inflammation and mucosal atrophy in the oral mucosa. Twenty-eight rats were divided into four groups. group (G) 1 was defined as control group, and G2 was the radiation therapy (RT) group. G3 and G4 were HMB/Glu/Arg control and 17 Gy RT plus HMB/Glu/Arg groups, respectively. A single dose of 17 Gy RT was given to the head and neck area, and the active supplement consisting of 5.2 g of HMB, 29.6 g arginine, and 29.6 g of glutamine which was equivalent to 60 kg adult dose was calculated for each rat and administrated orally. HMB/Glu/Arg started from the day of RT and continued until the animals were sacrificed 7 days after the RT. The extent of acute inflammation and mucosal atrophy for each rat was quantified with image analysis of histological sections of the oral mucosa. There were significant differences in terms of epithelial thickness, subepithelial edema, inflammation, and congestion between all groups (p values were < 0.001, 0.003, < 0.001, and 0.001 for each parameter, respectively). Using HMB/Glu/Arg alone led to hypertrophic changes in the epithelial layer. Moreover, when used with RT, HMB/Glu/Arg reversed radiation-induced epithelial atrophy (p, 0.006) and decreased radiation-induced inflammation at a significant level (p, 0.007). Concomitant use of HMB/Glu/Arg appears to ameliorate the radiation-induced acute inflammation and mucosal atrophy which represent the early phase of acute oral mucositis; however, this finding should be clarified with further clinical studies.Öğe Comparison of the effects of aromatase inhibitors and tamoxifen on radiation-induced lung toxicity: results of an experimental study(SPRINGER, 2013) Yavas, Guler; Yavas, Cagdas; Acar, Hilal; Toy, Hatice; Yuce, Deniz; Ata, OzlemThe purpose of this study is to compare the effects of anastrozole, letrozole and tamoxifen on radiation-induced pulmonary fibrosis. Eighty female Wistar albino rats were divided into eight groups. Group (G) 1 was defined as control group. G2 was radiation therapy (RT) only group. Groups 3, 4 and 5 were tamoxifen, anastrozole and letrozole control groups respectively. Groups 6, 7 and 8 were RT plus tamoxifen, anastrozole and letrozole groups, respectively. A single dose of 12 Gy RT was given to both lungs. Tamoxifen, anastrozole and letrozole were started 1 week before the RT and continued until the animals were sacrificed 16 weeks after the RT. As an end point, the extent of pulmonary fibrosis for each rat was quantified with image analysis of histological sections of the lung. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analyses. The congestion, inflammation and pulmonary fibrosis scores were significantly different between all the study groups (p values were < 0.001 for each). When compared with RT only group, concomitant RT and tamoxifen group increased the radiation-induced pulmonary fibrosis (p = 0.005). However, using either anastrozole or letrozole with RT did not increase the radiation-induced pulmonary fibrosis (p values were 0.768 and 0.752, respectively). Concomitant use of tamoxifen with RT seems to increase radiation-induced pulmonary toxicity. However, the use of both anastrozole and letrozole appears to be safe with concomitant RT, without increasing the risk of pulmonary fibrosis. This finding should be clarified with further clinical studies.Öğe Comparison of two different radiotherapy techniques in stomach cancer paiients who underwent concomitant chemoradiotherapy(Galenos Publishing House, 2014) Yavaş, Güler; Yavaş, Çağdaş; Çobanoğlu, Gökçen; Gül, Osman Vefa; Acar, Hilal; Ata, ÖzlemObjective: We aimed to compare four field radiotherapy techniques with three field radiotherapy technique with enhanced dynamic wedges (EDW) in patients with stomach cancer who underwent postoperative chemo-radiotherapy. Material and Methods: Ten consecutive stomach cancer patients who underwent total/subtotal gastrectomy and lymph node dissection were included to the study. For each patient, two different treatment plans were created for the tumor bed and regional lymph nodes. Three field and four field plans were compared for the doses in the planning target volume (PTV), the organ at risk (OAR) volumes (including kidneys, liver, spleen and spinal cord), the dose homogeneity index (DHI), and the monitor unit counts (MU) required for the treatment. Student-t test was used for statistical analysis. Results: There was no difference between two techniques in terms of DHI (p:0.576). The mean dose received by the liver was significantly reduced with three field technique (p<0.001); whereas the mean doses of the kidneys, spleen and spinal cord were decreased with four field technique (p values were 0.007, 0.021 and <0.001 respectively). The dose to %10, %30, %40 and %50 of the total liver volume were significantly reduced with three field technique (p values were 0.026, 0.009, 0.001 and <0.001 respectively). The MU counts required for the treatment was significantly lower with four filed technique (p<0.001). Conclusion: There weren't any difference in terms of dose homogeneity in the PTV and DHI between four field technique and three field techniques with EDW in patients with stomach cancer who underwent radiotherapy to the tumor bed and regional lymph nodes. It was expected to need more MU in the three field technique with EDW. The liver dose was significantly reduced with three field technique. Therefore it is more convenient to choose three field techniques with EDW in patients with known liver disease.Öğe Dosimetric comparison of 3-dimensional conformal and field-in-field radiotherapy techniques for the adjuvant treatment of early stage endometrial cancer(ELSEVIER SCI LTD, 2013) Yavas, Guler; Yavas, Cagdas; Acar, Hilal; Buyukyoruk, Ahmet; Cobanoglu, Gokcen; Kerimoglu, Ozlem Secilmis; Yavas, OzlemBackground: The purpose of this study is to compare field-in-field radiotherapy (FIF) with conformal radiotherapy (CRT) in terms of dosimetric benefits for early stage endometrial cancer patients. Materials and methods: Ten consecutive early stage endometrial cancer patients who underwent adjuvant external beam radiotherapy were included in the study. For each patient, two different treatment plans were created. FIF and CRT plans were compared for doses in the planning target volume (PTV), the organ at risk (OAR) volumes including rectum, bladder, bowel, bilateral femurs and bone marrow, the dose homogeneity index, and the monitor unit counts required for the treatment. Results: The FIF technique significantly reduced the maximum dose of the PTV, rectum, bladder, bowel, left femur, right femur and bone marrow (p values were: <0.001, 0.031, 0.003, <0.001, 0.001, 0.001 and <0.001 respectively). When the OAR volumes irradiated with >30 and >45 Gy were compared, the results were in favor of the FIF technique. The volumes of rectum, bladder, bowel, left femur, right femur and bone marrow receiving more than the prescription dose of 45 Gy were significantly reduced with FIF technique (p values were 0.016, 0.039, 0.01, 0.04, 0.037 and 0.01 respectively). The dose homogeneity index (DHI) was significantly improved with FIF technique (p < 0.001). Conclusions: FIF allowed more homogeneous dose distribution in the PTV and reduced the doses received by OAR. Considering the lower maximum doses in the OAR and PTV, FIF technique seems to be more advantageous than CRT during adjuvant radiotherapy for early stage endometrial cancer patients. (C) 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.Öğe Meme kanseri tanısı ile göğüs duvarına radyoterapi uygulanan hastalarda iki farklı tekniğin karşılaştırılması(2014) Yavaş, Çağdaş; Yavaş, Güler; Acar, Hilal; Ata, ÖzlemAmaç: Meme kanseri tanısı ile mastektomi olan hastaların tedavi planlamasında kullanılan alan içi alan (FIF) ve 3-boyutlu konformal radyoterapi (3B-KRT) tekniklerinin dozimetrik karşılaştırılması yapıldı. Gereç ve yöntemler: Meme kanseri tanısı ile modifiye radikal mastektomi operasyonu uygulanan yirmi hasta çalışmaya dahil edildi. Her hasta için göğüs duvarına yönelik iki farklı tedavi planı yapıldı. Planlanan hedef hacim (PTV), risk altındaki organlar (ipsilateral akciğer, kalp, sol asendan koroner arter ve karşı meme), doz homojenite indeksi (DHI) ve tedavi için gerekli olan monitör ünitler (MU) açısından FIF plan ile 3B-KRT planları karşılaştırıldı. İstatistiksek analizde student t test kullanıldı. Bulgular: FIF tekniği kullanıldığında PTV ve ipsilateral akciğerdeki maksimum dozlar anlamlı olarak azaldı. Aynı şekilde, ipsilateral akciğer hacminin % 30'unun aldığı doz FIF tekniği ile anlamlı olarak azaldı. FIF tekniği ile daha az MU kullanılarak daha homojen doz dağılımı elde edildiği görüldü. Sonuç: Meme kanseri nedeni ile göğüs duvarına yönelik radyoterapi uygulanan hastalarda FIF tekniği ile 3B-KRT karşılaştırıldığında FIF tekniğinin PTV'de daha iyi bir doz dağılımı sağladığı görülmüştür. Ayrıca, tedavi için gerekli olan MU'nun daha düşük olması da göz önüne alındığında FIF tekniği göğüs duvarı ışınlamalarında 3B-KRT'ye göre daha avantajlı olarak görünmektedir
