Theses supervised by Prof. Dr. Ercan Yılmaz
16 theses · Bolu Abant İzzet Baysal University, İnönü University
Effects of ionizing radiation on the memory–based device with Yb2O3 as a charge trapping layer
In this thesis, we have studied the effect of annealing temperature and gamma irradiation on the Al/Al2O3/Yb2O3/Al2O3/n-Si charge trapping memory (CTM) devices. The Al2O3 oxide was utilized as the tunneling oxide and blocking oxide respectively, while Yb2O3 was used as charge trapping oxide. The thin films were deposited by sputtering technique. The samples were then annealed at 200oC 400oC, 600oC, and 800oC in N2 ambient for 40 min, while one sample was kept as-deposited. The crystallinity stucture and surface morphologies of thin films were analysed by X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. The value of root mean square (RMS) increased with an increase in the annealing temperature. The electrical characteristics of the devices were also analysed through capacitance-voltage(C-V) curves. The capacitancevalue in the accumulation region decreased with an increase in the annealing temperature. The memory window (∆𝑉𝑓𝑏) at several annealing temperature by sweeping voltage of -10V to +10V and back forth has also been studied. The device which was annealed at 200℃ had a largest ∆𝑉𝑓𝑏 8.60 and the highest capacitance at accumulation region than other devices. This could be related to the better charge storage capability of the CTM device. On the other hand, the ∆𝑉𝑓𝑏 at different sweeping voltage between ±8V and ±10V were investigated for several annealing temperature. In addition, the radiation response on CTM device has also been studied intensively through C-V characteristics by using Cs-137 gamma ray source in the dose range of 4Gy to 128Gy. The C-V curves slightly shifted both in the positive and negative voltage direction. This suggesting oxide trapped(ΔNot) and interface trapped(ΔNit) charges were induced by irradiation. It has also been shown that radiation has no significant impact on the memory window. KEYWORDS:CMTdevices, Thinfilms, PDA, Gamma irrradiation, memorywindow.
Fabrication and characterization of the stacked nuclear radiation sensing field effect transistors (NürFETs) with high-K
NürFETs are integrated ionizing radiation sensors that operate on the principle of converting radiation-induced threshold voltages into absorbed doses, which are commonly used to measure absorbed doses in spacecraft, military, high energy physics laboratories, and radiotherapy. However, one of the major drawbacks of the conventional NürFETs is the inability to sense and detect very low radiation doses at the mGy range, which are needed for personal dosimeter and low radiation environments. In this study, the NürFETs with a stacked structure, a design method, where NürFETs are coupled in a stacked structure (stacked-NürFETs) were fabricated. The stacked-NürFETs structure approach was designed to improve the sensitivity of single NürFETs and the performance of the stacked-NürFETs as radiation sensors were investigated and discussed. The pre-irradiation electrical characteristics of the device were evaluated, and the initial threshold voltages (Vth) have shifted to larger negative voltage values, which are proportional to the number of the NürFETs increased in the stacked-NürFETs structure. The post-irradiation electrical characteristics of the device were obtained, and their responses to irradiation and possible usages in radiation dosimetry have been investigated and discussed. The results demonstrate that the sensitivities of the stacked-NürFETs are directly proportional to the number of sensors used in the stacked-NürFETs structure.
Silicon nano-wire fabrication and its applications
This thesis focuses on the fabrication of silicon nanowires and their applications in MOS capacitors. Silicon nanowires (SiNWs) were fabricated using the metal-assisted chemical etching method (MACE) and AgNO3, HF, and H2O2 were used as the precursors during the process. Silicon nanowires were fabricated by using three different samples of silicon substrates and were etched in HF/H2O2/H2O for 10 min, 30 min, and 60 min. Subsequently, SiO2 was grown onto n-Si (100) and SiNWs/n-Si (100) substrates by using both dry and wet oxidation methods in a diffusion furnace at 1000℃ for 30min. The crystalline structures and surface morphologies of SiNWs and SiO2/SiNWs were investigated by x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. To investigate the electrical characteristics of the capacitors, the capacitance-voltage(C-V) measurements were performed at 1MHz for the MOS capacitor without SiNWs and the length of 1µm, 2µm, and 4µm SiNWs capacitors. MOS capacitor without SiNWs was found to have the highest capacitance value and the highest calculated dielectric constant value of about 4.18. However, the value of the oxide capacitance in the accumulation region decreased with an increase in the length of the SiNWs capacitor. The 1µm SiNWs capacitor was chosen as the optimum because this capacitor had the highest oxide capacitance and highest k- value compared to other SiNWs capacitors. Therefore, this capacitor was irradiated by using a gamma-ray source at different doses ranging from 1Gy to 40Gy. It was found that the capacitance value increased with an increase in the radiation dose. Moreover, the results demonstrated that interface states density(D_it ), oxide trap(〖∆N〗_ot ) and interface trap charges ∆N_it were induced during gamma irradiation.
Total ionization dose effects on the charge storage capability of Er2O3/HfO2/Er2O3 based memory cell
Co-60 gamma radiation effects on the charge storage capability of the Er2O3/HfO2/Er2O3 based charge trapping memory (CTM) cell were studied in detail. In addition, the structural and electrical characteristics of the CTM cell were also analyzed. Transmission Electron Microscopy (TEM) was used to analyze the structural characteristics of the CTM cell. To analyze the electrical characteristics of the cell, Capacitance-Voltage (C-V) and Conductance-Voltage (G/w-V) measurements were taken for CTM cell samples left as-deposited, and those annealed at 3500C and 7000C. The memory window was seen to increase with increasing post- deposition annealing (PDA) temperature which was attributed to an increase in the oxide trap charges. 7000C was chosen as the optimum PDA temperature because the CTM cell annealed at this temperature possessed the largest memory window and a high oxide capacitance. Gamma radiation was then used to analyze the radiation effects on the electrical characteristics of the CTM cell. The Er2O3/HfO2/Er2O3 based CTM cell was found to be promising for radiation environments.
Fabrication and applications of biosensor for early diagnosis of lymphoma cancer and cancer metastasis
Lymphoma cancer ranked as the fifth cancer type is seen all around the world and death caused by lymphoma shows increment day after day. To prevention of death caused by lymphoma cancer, in the conducted study we fabricated rGO-FET biosensor device for early detection of lymphoma cancer. To do so, we synthesized the reduced graphene oxide from bulk graphite as sensing area. The fabrication of FET base structure was done by using microelectronic technology and rGO was transferred onto FET structure for use as sensing area. The characterization of rGO was completed by investigation XRD, Raman, FTIR and TEM analysis. These analysis results showed that synthesized rGO is suitable for detection. The first trials of rGO-FET biosensor were completed with various pH solutions. The pH trials revealed that the capability of rGO-FET biosensor device. For the early detection of lymphoma, the miRNA sequences were used for functionalization. The probe sequence was immobilized onto rGO sensing area for the miRNA studies. miRNA-155 sequence was dropped onto probe sequence and electrical measurements has been completed by analyzing I-V curves. The I-V curves revealed that the probe sequence immobilized on rGO matched with various concentration contained miRNA-155 sequence samples and shift was observed towards to left side with increasing concentration. The specificity study revealed that the probe sequence only matched with miRNA-155 sequence. The selectivity studies showed that rGO-FET biosensor can distinguish various concentrations. The results showed that rGO-FET can define miRNA-155 concentrations between 100 pM and 10 µM. The Limit of detection (LOD) was determined as 100 pM. Overall results suggested that the rGO-FET biosensor device successfully fabricated and can be used for early detection of lymphoma cancer and cancer metastasis.
Akciğer kanseri ve kanser metastazı erken tanısı için biyosensör üretimi ve uygulamaları
Lung cancer has one of the greatest mortality rates of all cancer varieties. This malignancy affects millions of people throughout the globe and in our country. Unfortunately, it is too late to diagnose the disease using traditional methods because they are insufficient. This necessitates the development of a method or device for early disease diagnosis. A biosensor to detect lung cancer and metastasis at an early stage has been investigated in this study. Biosensors based on GFET are preferred. Utilizing the Hummer procedure, graphite was converted into reduced graphene oxide. FTIR, Raman spectroscopy, transmission electron microscopy, and X-ray diffraction were used to examine the properties of graphene oxide (GO) and reduced graphene oxide (rGO). The outcomes demonstrated that the production met the intended standards. The rGO that has been synthesized has been deposited on the FET structure using a technique within the scope of this research. Micro RNAs were favored as biomarkers for malignancy. The biosensor's electrical properties were determined using the output characteristic and transfer characteristic method. The device's Id-Vd measurements revealed that the rGO layer between the source and the drain formed a successful ohmic contact. In Id-Vgs measurements, pH-dependent measurements of an ionic solution were taken first, with linear results. The consistency of subsequent measurements of the analyte linked to miRNA was comparable. The device was then evaluated with an analyte containing an incompatible miRNA to ascertain its selectivity. The test revealed that the device's sensitivity was limited to its own biomarker. Finally, the biosensor's sensitivity was evaluated. The solution of the analyte was diluted from 10M to 100 pM and then applied to the sensor. At 100 pM, the biosensor produced a significant response. At the conclusion of the study, a biosensor was created that, if implemented, could detect lung cancer at an early stage.
The influence of gamma irradiation on charge storage capability of HFO2/DY2O3/AL2O3 based charge trapping memory cell
The impact of annealing temperature and Cs-137 gamma-ray irradiation on Al/ HfO2/Dy2O3/Al2O3/n-Si (100) charge trapping memory (CTM) devices has been examined in this thesis. E-beam evaporation and RF magnetron sputtering procedures were both used to deposit the thin films. The samples were annealed at 300oC, 500oC, 700oC and 900oC in N2 ambient for 40min, while one sample was left as-deposited. The XRD and AFM were used to study the crystalline structure and surface textures of the thin film. It has been observed that the sample annealed at 900oC had only one weak peak (400) of Dy2O3 while other samples turned amorphous. With an increase in annealing temperature, the surface textures have been found to diminish. The lowest RMS value of 2.06nm was found at 900oC. The impact of frequency and annealing temperature on the CTM devices has been investigated through C-V curves. We found that interface state density had a huge impact on the value of capacitance in the accumulation region. It has also been found that the C-V curves decreased with an increase in the annealing temperature between 500oC and 900oC. This might be plausibly due to the formation of dangling bonds and interfacial layers at higher annealing temperatures. The C-V curves have been observed to be shifted to the positive and negative direction, respectively. The memory window (∆Vfb) were analysed and studied through the C-V hysteresis curves for various annealing temperature at -10V to +10V and back. The device annealed at 500oC was found to have a larger ∆Vfb of 0.44V compared to other devices. The ∆Vfb were obtained at different sweeping between ±10V and ±12. The largest memory window of 8.22V was achieved at ±12V for the device annealed at 700oC. This could be related to the good charge storage capability. The effect of radiation on CTM devices has also been studied intensively through C-V curves by using Cs-137 gamma-ray source in different doses of 4Gy to 128Gy. There was a shift both in ΔVmg and ΔVfb evinced from the C-V curves due to the ΔNot and ΔNit charges that were generated by irradiation. Moreover, the memory window was found to increase with an increase in the radiation dose.
Yüksek verimli PIN foto diyot üretilmesi ve tıbbi uygulamalar için değerlendirilmesi
Today, radiation safety has become an extremely important issue. Therefore, tracking the doses of radiation that people who work in radiated environments are instantly exposed to is extremely important. While passive dose measuring devices used for this purpose are successful in measuring the dose exposure rate, reading the dose information that these devices measure is a considerable waste of time. For this reason, it is extremely important to get the dose information in the medium instantly. Semiconductor-based sensors have been studied extensively in the literature, and the results have shown that silicone-based photodiodes are very successful in instantaneous dose mortality, and Si-PIN PDs are well-designed to measure instant dose speeds. However, the architectural design of a Si-PIN PD, which is planned to be used in radiation sensing, and the knowledge of the variables necessary for the production of this structure are critical. In the literature, the radiation responses of produced Si-PIN PDs are studied, but the data shared on production is quite insufficient. In this study, the Si-PIN PD architecture was designed using Silvaco software tools. The electrical properties of the designed Si-PIN PDs have been studied using ATLAS software to obtain the most suitable original Si- PIN PD architecture for use in dosimeters. The variables of the production stages have been determined using the Silvaco ATHENA tool so that the resulting architecture can be produced in a laboratory environment. After the completion of the design, electrical tests of Si-PIN PDs were carried out, X-rays test of Si-PIN PD's were performed in ion chamber conditions. Subsequently, radiation spectroscopy from 204Tl, 90Sr sources was analyzed. The results show that Si-PIN PDs are promising for future use in healthcare applications.
PIN foto diyot sensörlerinin üretimi ve karakterizasyonu
p-type, intrinsic, n-type (PIN) photodiodes with active areas of 3.5 x 3.5 mm2, 5.0x5.0 mm2, and 7.0x7.0 mm2 were fabricated using the conventional photolithography method on a 6 inch (100) intrinsic silicon wafer with a surface resistivity of 2.4 kΩ - 2.8 kΩ at 500 μm thicknesses. n and p regions were formed using the phosphorus (POCl3) and boron (BBr3) doping at 950 °C via thermal diffusion method. As expected for the capacitance – voltage (C-V) characteristic of the fabricated PIN photodiodes decreases exponentially with the reverse-biased voltage. The capacitance of each PIN diode reached a fully depleted point at -5V. The capacitance was measured at the fully depleted point as the order of pF. The dark current-voltage (Id-V) characteristics of the PIN diodes were measured at room temperature in the reverse biased. Thanks to the structure of the PIN diodes, they have worked on high voltages without breakdown. However, due to the effects of high voltage and the effects of silicon temperature dependency, the dark current is observed in µA at breakdown voltage. At lower voltages, the dark currents drop to nA. Silicon PIN photodiodes, which are produced according to the results of quantum efficiency and spectral responses, can detect wavelengths between 380 nm and 1100 nm and have reached maximum efficiency at 810 nm wavelength. The fabricated PIN diodes can be used in optoelectronic applications.
Fabrication and characterization of doped metal-oxide thin film gas sensors
Tin-oxide based thin film gas sensors were produced by Electron Beam Evaporation (e-beam) method and annealed at 600oC. The structural, morphological, chemical and the electrical properties of SnO2/SiO2 thin films were studied in detail. The structural analysis were obtained by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) was used for analyzing the morphological properties of the thin film. Also chemical bonding structures were analyzed via Fourier Transform Infrared Spectroscopy (FTIR) and electrical properties of the SnO2/SiO2 thin films were investigated by using current-voltage (I-V) characteristics measurement. Then, by using sputtering technique the Platinum (Pt) was doped onto the produced thin film in 1 second, 3seconds, and 5 seconds respectively. The same structural, morphological, chemical, and the electrical properties of the Pt doped thin films were investigated and discussed. Finally, the Oxygen sensing property of the each fabricated SnO2/SiO2 thin films and the effect of Pt doping on gas sensitivity were investigated and discussed in this study.
Yüksek-K dielektrikli alan etkili nükleer radyasyon dedektörlerinin (NürFET) üretimi ve karakterizasyonu
The continuous development of a gate stack system and continually shrinking gate-dielectric thickness, have been necessitated by the requirement of higher gate capacitance in order to reduce excessive leakage currents in Metal- Oxide- Semiconductor Field- Effect transistors (MOSFETs). To obtain high gate capacitance and inhibit tunneling, relatively thick insulators with high dielectric constants (high-k) are needed in place of SiO2 gate dielectric in MOSFETs. In this thesis, the Hafnium Oxide (HfO2) and Erbium Oxide (Er2O3) have been used as two distinct high-k dielectrics as an alternative gate dielectric materials to conventional SiO2. Although several technological applications of the HfO2 and Er2O3 dielectrics are available in microelectronics, there still exists reliability problem for the usage of them in radiation environments. The detailed investigation should be performed for the realistic microelectronic applications of high- k materials. Hence, in the scope of this thesis, the MOSFETs with HfO2 and Er2O3 gate dielectrics have been fabricated and the possible device usage as a radiation sense materials for defense/space applications and/or radiation soft materials for possible dosimeter applications have been discussed. The device used for the dosimetric purposes, called Nuclear Radiation Sensing Field Effect Transistor (NürFET), is discrete p-channel MOSFET. In addition, the device failure mechanisms including the structural, morphological, electrochemical and electrical changing under radiation environment have also been discussed in details for understanding behaviors of the high- k based devices under radiation environment. The high-k device characteristics have been compared to experimentally fabricated and commercially available conventional devices with SiO2 gate.
Kadmiyum çinko telleryum radyasyon dedektörlerinde kullanılan kadmiyum çinko telleryum ince filmlerin yapısal ve optik karakterizasyonu
The microstructural and morphological characterizations of Cadmium Zinc Tellur (CZT) thin films were studied in details. The CZT thin films were deposited on glass substrates at 200, 300 and 400 °C by radio frequency magnetron sputtering technique and annealed at 200, 300 and 450 °C for an hour under N2 and mixed N2H2 ambient at atmospheric pressure. X-ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), and UV transmission spectroscopy measurements were performed. The XRD measurements emphasized that the annealed CZT films have a cubic-oriented (111), (220) and (311) polycrystalline structure, whereas as deposited films are mostly-amorphous. The effects of sputtering and annealing temperatures on the composition of the thin films were also discussed. EDS analysis was used to study the chemical composition of source and CZT thin films. SEM was used for surface morphology. It was concluded that post-annealing and deposition temperatures have explicitly effects on variation of the CZT thin film structure and morphology. AFM was used to study roughness of the CZT thin films which deposited under various sputtering and annealing temperatures. Then XPS measurements were performed in the depth profiling mode to comprehend the chemical composition of the films. Finally, transmission measurements were performed to find out band gaps of the samples. The optimum conditions were revealed for CZT deposition in accordance with their applications.
BiFeO3 ince filmlerin yapısal ve elektriksel özellikleri ve radyasyon sensörü olarak kullanımı
In this thesis, the structural and electrical characterization of BiFeO3 thin films and possible usage of BiFeO3 in MOS based radiation sensors were investigated. BiFeO3 thin films were deposited on (100) p-type silicon wafers with a thickness about 300 nm by magnetron sputtering. The deposited thin films were divided into two groups. First group samples were annealed at 550°C for 30 minutes under atmospheric environment. The second group samples were kept as-deposited. Structural characterizations were studied by using XRD and SEM measurements before and after annealing of samples. The BiFeO3 MOS capacitors were fabricated in both annealed and as-deposited samples by using evaporation technique. High frequency C-V measurements were performed for both type samples, but frequency dependent C-V hysteresis and G/ω-F measurements were carried out for annealed samples exhibited the desired characteristic. To examine their gamma irradiation response of the annealed ones, the devices were irradiated up to 16 Gray by using the GAMMACELL 220 Co-60 radioactive source at a dose rate of 0.0030 Gy/s. C–V measurements were recorded prior to and after irradiation and the effects of radiation were determined from the mid-gap and flat-band voltage shifts. The results show that BiFeO3 can be used as dielectric layer for future dielectric applications such as radiation sensors.
Erken evre endometriyum kanserinde prognostik faktörlerin belirlenmesi
Amaç: Bu çalışmanın amacı erken evre endometriyum kanseri olgularında prognostik faktörleri belirlemektir. Gereç ve Yöntem: Ocak 2011- Aralık 2022 tarihleri arasında, İnönü Üniversitesi Tıp Fakültesi Kadın Hastalıkları ve Doğum Kliniğinde opere edilen ve takibi yapılan endometrium kanseri olguları retrospektif olarak tarandı ve bu olgular içerisinde FIGO evrelemesine göre erken evre (Evre Ia, Ib ve II) olan 241 hasta değerlendirmeye alındı. Bulgular: Çalışmamıza dahil edilen hastaların median yaşı 57 olup (en düşük: 34 -en yüksek: 86), 181 hastada (%75.10) evre Ia, 47 hastada (%19.50) evre Ib ve 13 hastada (%5.40) ise evre II endometriyal kanser saptandı. Gravida, parite, serum CA-125 seviyeleri ve histolojik derecenin mortalite gelişmeyen hasta grubunda anlamlı şekilde yüksek olduğu saptandı (sırasıyla p=0.011, p=0.047, p<0.001 ve p=0.029). Univariate regresyon analizinde artmış serum CA-125 düzeyleri [Hazard ratio (HR), 1.009; 95% Confidence Interval (CI), 1.003–1.016; p=0.004)], artmış hastalık evresi (HR, 2.69; %95 CI, 1.009–6.722; p=0.048) ve artmış histolojik grade'in (HR, 4.85; %95CI, 1.35–17.40; p=0.015) daha kısa genel sağkalım (OS) ile ilişkili olduğu saptandı. Multivariate analiz, histolojik grade'in hem OS'ı hem hastalıksız sağkalım (DFS)'ı bağımsız olarak öngördüğü sonucunu ortaya koydu (sırasıyla HR, 5.942; %95CI, 1.593–22.158; p=0.008; HR, 4.830; %95CI, 1.487–15.687; p=0.009). Sonuç: Çalışmamız erken evre endometrial kanser hastalarında histolojik tümör grade'inin hem OS hem de DFS için bağımsız belirleyici olduğu sonucunu ortaya koydu. Bu çalışmanın bulguları erken evre endometriyum kanseri vakalarında intraoperatif frozen kesit analizinde yüksek histolojik tümör grade'i saptanması durumunda kapsamlı bir değerlendirme sağlamak için tam bir cerrahi evreleme yapılması gerektiği önermesini desteklemektedir. Anahtar Kelimeler: CA-125 antijeni, Endometriyum Kanseri, Hastalıksız sağkalım, Prognoz, Sağkalım analizi.
Antenatal dönemde ölçülen umblikal kord koiling indeksinin gebelik sonuçlarına etkisi
Amaç: İntrauterin yaşamda bebekle anne arasındaki bağı oluşturan ve fetüsün gelişimini sağlayan umbilikal kordon vardır. Birçok çalışmada umbilikal kordun kıvrımsal yapısının, az kıvrımlı veya çok kıvrımlı olmasının gebelik üzerine olumsuz etkileri olduğu öngörülmüştür. Bu çalışmanın amacı; ikinci trimesterda, primigravid gebelerde bakılan, umbilikal kordunkıvrımsal yapısının karakteristiğinin, gebelik üzerine etkisinin araştırılmasıdır. Gereç ve Yöntem: Çalışmaya 461 tane primigravid gebe dahil edildi. 18-24 gebelik haftaları arasında ultrasonografik olarak bakılan gebelerde, umbilikal kord koiling indeksi hesaplandı. Umbilikal koil indeksine göre hastalar; hipokoil (az kıvrımlı), normokoil(normal), hiperkoil (çok kıvrımlı) olacak şekilde üç gruba ayrıldı. Gebelikte gelişebilecek hastalıklar (Gestasyonel Diyabetes Mellitus, Gestasyonel Hipertansiyon, Preeklampsi, İntrauterin gelişme geriliği, Oligohidroamniyos) açısından takipleri yapıldı. Hastaların doğum haftaları ve doğum şekilleri kaydedildi. Doğum sırasında fetal distres gelişen hastalar kaydedildi. Bebek doğum ağırlıkları, mekonyumlu doğum olup olmamasına, kord kan gazı pH'ına, bebeklerin beşinci dakika Apgar skorlarına, plasenta ağırlığı ve kalınlığına bakıldı. Veriler SPSS.22 istatistiksel program kullanılarak değerlendirildi. Bulgular: Umbilikal kord koiling indeksinin, hipokoil ve hiperkoil olma durumunun, bebek doğum ağrılığının küçük olması, İntrauterin gelişme geriliği oluşması, oligohidroamniyos gelişmesi, fetal distres gelişimi, mekonyumlu doğum olması ve daha asidoza kaymış kan gazı pH ı ve beşinci dakika Apgar skorlarının daha düşük olması ile ilişkili olduğu saptanmıştır. Diğer taraftan koiling indeksinin erken doğum, Gestasyonel Diyabetes Mellitus, Gestasyonel Hipertansiyon, preeklampsi, plasenta dekolmanı ve fetal ölümle ilişkili olmadığı saptanmıştır. Sonuçlar: İkinci trimestırda rutin ultrasonografi muayenesi sırasında, muayene süresini çok uzatmayacak olan kord koiling indeksine bakmak birçok gebelikte gelişebilecek hastalıklar açısından fikir verebilir.
Plasenta akreta spektrumu olgularının maternal ve neonatal sonuçlarının retrospektif analizi: Antenatal risk faktörlerinin etkisinin ve yönetim yaklaşımlarının araştırılması
Amaç: Bu çalışmanın amacı plasenta akreta spektrumu (PAS)'nun erken tanı ve tedavi yaklaşımlarını değerlendirmek ve uygulanan tedavi modalitelerinin maternal ve neonatal sonuçlar üzerindeki etkilerini incelemektir. Materyal ve Metot: Çalışmaya, 1 Ocak 2014-25 Mart 2024 tarihleri arasında İnönü Üniversitesi Tıp Fakültesi Kadın Hastalıkları ve Doğum Anabilim Dalında PAS tanısı konulan ve tedavisi gerçekleştirilen 210 hasta dahil edilmiştir. Hastaların klinik ve demografik özellikleri, cerrahi yöntemler, maternal ve neonatal sonuçlar retrospektif olarak incelenmiştir. Bulgular: Hastaların %66.67'sine elektif, %33.33'üne acil cerrahi uygulanmıştır. Uterus koruyucu cerrahi yapılan hastalarda akreta ve inkreta oranları daha yüksekken, histerektomi yapılanlarda perkreta oranı anlamlı şekilde fazladır. Elektif doğum yapanların yenidoğan kilosu, 1. ve 5. dakika APGAR skorları anlamlı olarak daha yüksek bulunmuştur (P<0.001). Acil doğum yapanlarda gebelik yaşı daha düşük, intraoperatif kan kaybı ve neonatal komplikasyon oranları ise anlamlı derecede yüksektir. Ayrıca acil doğum grubunda üreter hasarı daha sık görülürken, elektif grupta mesane yaralanmaları daha fazladır (P=0.024). Cerrahi yönetime göre histerektomi ve koruyucu cerrahi uygulanan hastaların preoperatif ve postoperatif hemoglobin ve hemotokrit değerleri benzer saptandı (sırasıyla p=0.397. p=0.406). Preoperatif ve postoperatif hemoglobin ile hematokrit değerlerinde cerrahi yönetimlere göre belirgin bir fark tespit edilmedi. Plasentanın anterior yerleşimi, komplet invazyon ile ilişkili bulundu (P<0.001). Sonuç: Bu PAS ile komplike gebeliklerde acil şartlarda gerçekleştirilen doğumların planlı doğumlara göre daha yüksek komplikasyon riski taşıdığı gözlenmiştir. Bu çalışmanın sonuçlarına dayanarak PAS yönetiminde erken tanı ve doğum planlamasının kritik öneme sahip olduğu söylenebilir. Maternal ve neonatal sonuçları iyileştirmek için plasenta invazyon tipine uygun cerrahi yaklaşımlar geliştirilmesi ve bireyselleştirilmiş bir yönetim planı uygulanması gerektiği sonucuna varılmıştır. Anahtar Kelime: Cerrahi işlemler, gebelik komplikasyonları, plasenta akreta, uterus kanamaları