Browsing by Author "Ayyildiz, Oguzhan"

Now showing 1 - 5 of 5

Comparison of Lung Tumor Segmentation Methods on PET Images
(IEEE, 2015) Eset, Kubra; Icer, Semra; Karacavus, Seyhan; Yilmaz, Bulent; Kayaalti, Omer; Ayyildiz, Oguzhan; Kaya, Eser; 0000-0002-8473-9720; 0000-0003-2954-1217; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Yilmaz, Bulent; Ayyildiz, Oguzhan
Akciğer kanseri, tüm dünyada kansere bağlı gerçekleşen ölümlerin en sık nedenidir. Son zamanlarda, tümör içi 18Fflorodeoksiglukoz (FDG)’un tutulumunun düzgünlük, pürüzlülük ve düzenliliğini (yani tekstür özelliklerini) tanımlamak için PET görüntüleri üzerinde çeşitli görüntü işleme yaklaşımları kullanılmaktadır. Bunun ilk ve önemli aşaması tümörlü bölgenin diğer bölgelerden başarıyla ayrıştırılması, yani segmentasyonudur. Bu çalışmada, 36 hastadan alınan tek veya çok kesit görüntüler üzerinde kortalamalar, aktif kontur (yılan), Otsu eşikleme yaklaşımlarını kullanarak elde edilmiş alan ve hacimlerin ekibimizdeki nükleer tıp uzmanı tarafından değerlendirmesiyle karşılaştırması yapılmıştır. Sonuç olarak, Otsu eşikleme algoritmasının daha seçici davrandığı gözlenmiştir
Lung cancer subtype differentiation from positron emission tomography images
(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, ATATURK BULVARI NO 221, KAVAKLIDERE, ANKARA, 00000, TURKEY, 2020) Ayyildiz, Oguzhan; Aydin, Zafer; Yilmaz, Bulent; Karacavus, Seyhan; enkaya, Kubra; Icer, Semra; Tasdemir, Arzu; Kaya, Eser; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
Lung cancer is one of the deadly cancer types, and almost 85% of lung cancers are nonsmall cell lung cancer (NSCLC). In the present study we investigated classification and feature selection methods for the differentiation of two subtypes of NSCLC, namely adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). The major advances in understanding the effects of therapy agents suggest that future targeted therapies will be increasingly subtype specific. We obtained positron emission tomography (PET) images of 93 patients with NSCLC, 39 of which had ADC while the rest had SqCC. Random walk segmentation was applied to delineate three-dimensional tumor volume, and 39 texture features were extracted to grade the tumor subtypes. We examined 11 classifiers with two different feature selection methods and the effect of normalization on accuracy. The classifiers we used were the k-nearest-neighbor, logistic regression, support vector machine, Bayesian network, decision tree, radial basis function network, random forest, AdaBoostM1, and three stacking methods. To evaluate the prediction accuracy we performed a leave-one-out cross-validation experiment on the dataset. We also considered optimizing certain hyperparameters of these models by performing 10-fold cross-validation separately on each training set. We found that the stacking ensemble classifier, which combines a decision tree, AdaBoostM1, and logistic regression methods by a metalearner, was the most accurate method for detecting subtypes of NSCLC, and normalization of feature sets improved the accuracy of the classification method.
Metabolic Imaging Based Sub-Classification of Lung Cancer
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA, 2020) Bicakci, Mustafa; Ayyildiz, Oguzhan; Aydin, Zafer; Basturk, Alper; Karacavus, Seyhan; Yilmaz, Bulent; 0000-0001-5810-0643; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
Lung cancer is one of the deadliest cancer types whose 84% is non-small cell lung cancer (NSCLC). In this study, deep learning-based classification methods were investigated comprehensively to differentiate two subtypes of NSCLC, namely adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). The study used 1457 F-18-FDG PET images/slices with tumor from 94 patients (88 men), 38 of which were ADC and the rest were SqCC. Three experiments were carried out to examine the contribution of peritumoral areas in PET images on subtype classification of tumors. We assessed multilayer perceptron (MLP) and three convolutional neural network (CNN) models such as SqueezeNet, VGG16 and VGG19 using three kinds of images in these experiments: 1) Whole slices without cropping or segmentation, 2) cropped image portions (square subimages) that include the tumor and 3) segmented image portions corresponding to tumors using random walk method. Several optimizers and regularization methods were used to optimize each model for the diagnostic classification. The classification models were trained and evaluated by performing stratified 10-fold cross validation, and F-score and area-under-curve (AUC) metrics were used to quantify the performance. According to our results, it is possible to say that inclusion of peritumoral regions/tissues both contributes to the success of models and makes segmentation effort unnecessary. To the best of our knowledge, deep learning-based models have not been applied to the subtype classification of NSCLC in PET imaging, therefore, this study is a significant cornerstone providing thorough comparisons and evaluations of several deep learning models on metabolic imaging for lung cancer. Even simpler deep learning models are found promising in this domain, indicating that any improvement in deep learning models in machine learning community can be reflected well in this domain as well.
Prognostic significance of the texture features determined using three dimensional 18F-FDG PET images: new potential biomarkers
(SOC NUCLEAR MEDICINE INC1850 SAMUEL MORSE DR, RESTON, VA 20190-5316, 2016) Karacavus, Seyhan; Yilmaz, Bulent; Kayaalti, Omer; Tasdemir, Arzu; Kaya, Eser; Icer, Semra; Ayyildiz, Oguzhan; Eset, Kubra; Vardareli, Erkan; Asyali, Musa; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Yilmaz, Bulent; Ayyildiz, Oguzhan
Prognostic significance of the texture features determined using three dimensional 18F-FDG PET images: new potential biomarkers
Registration and Fusion of Lung Tumor PET/CT Images
(IEEE, 2015) Ayyildiz, Oguzhan; Yilmaz, Bulent; Karacavus, Seyhan; Kayaalti, Omer; Icer, Semra; Eset, Kubra; Kaya, Eser; 0000-0003-2954-1217; 0000-0002-8473-9720; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Ayyildiz, Oguzhan; Yilmaz, Bulent
Görüntü birleştirme medikal alanda tamamlayıcı yönüyle ve teşhis ve tedavi planlama gibi uygulamalarda kullanılmasıyla dikkat çekmektedir. Bu çalışmada 8 adet küçük hücre dışı akciğer kanserli hastanın positron emisyon tomografi (PET) ve bilgisayarlı tomografi (BT) görüntüleri önce çakıştırılmış sonra dalgacık ve temel bileşen analizi metotlarıyla birleştirilmiştir. Karşılıklı bilgi ve eğitimli gözle kıyaslama sonucunda dalgacık daha başarılı bulunmuştur.