Publications by authors named "Bahar Dirican"

Background: Adaptive radiation therapy (ART) refers to redesigning of radiation therapy (RT) treatment plans with respect to dynamic changes in tumor size and location throughout the treatment course. In this study, we performed a comparative volumetric and dosimetric analysis to investigate the impact of ART for patients with limited-stage small cell lung cancer (LS-SCLC).

Methods: Twenty-four patients with LS-SCLC receiving ART and concomitant chemotherapy were included in the study.

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Background: There is a paucity of data on the management of recurrent lymph nodes after primary or adjuvant radiotherapy (RT) for prostate cancer (PCa). In this study, we report our tertiary cancer center experience with stereotactic body radiotherapy (SBRT) for the management of pelvic lymph node recurrences after adjuvant or primary RT for PCa.

Materials And Methods: Patients who underwent SBRT for pelvic lymph node metastases from PCa between 2013 and 2019 were retrospectively assessed for local control (LC), androgen deprivation treatment-free survival (ADT-FS), and toxicity outcomes.

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Pilocytic astrocytoma (PA) may be seen in both adults and children as a distinct histologic and biologic subset of low-grade glioma. Surgery is the principal treatment for the management of PAs; however, selected patients may benefit from irradiation particularly in the setting of inoperability, incomplete resection, or recurrent disease. While conventionally fractionated radiation therapy has been traditionally utilized for radiotherapeutic management, stereotactic irradiation strategies have been introduced more recently to improve the toxicity profile of radiation delivery without compromising tumor control.

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The purpose of the study is that introduce novel universal Conformity Index (CI) and Unconformity Index (UCIs) Algorithms that can be used for all radiotherapy treatment planning methods. The applicability of existing CIs has been reviewed and analyzed for each radiotherapy plan dose distribution. Novel CI and UCIs have been derived in this study to complement the calculation deficiencies.

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Lung cancer is a global health concern as the leading cause of cancer related mortality worldwide. Small cell lung cancer (SCLC) poses a formidable challenge to the treating physicians with the worst prognosis among all lung cancers. However, limited stage SCLC (LS-SCLC) has a relatively better outcome with multimodality management.

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Background: Vertebral hemangiomas are defined as benign proliferation of blood vessels. Vertebral hemangiomas are generally found incidentally by computerized tomography or magnetic resonance imaging; however, they may also cause pain and quality-of-life impairment in some circumstances with reference to their location and association with the spinal cord. In this study, we assessed the utility of image-guided radiation therapy (IGRT) in the management of patients with painful vertebral hemangioma.

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Background: Currently, CBCT system is an indispensable component of radiation therapy units. Because of that, it is important in treatment planning and diagnosis. CBCT is also an crucial tool for patient positioning and verification in image-guided radiation therapy (IGRT).

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Brain tumors, which are among the most common solid tumors in childhood, remain a leading cause of cancer-related mortality in pediatric population. Gliomas, which may be broadly categorized as low grade glioma and high grade glioma, account for the majority of brain tumors in children. Expectant management, surgery, radiation therapy (RT), chemotherapy, targeted therapy or combinations of these modalities may be used for management of pediatric gliomas.

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Background: The aim of our study is to assess the dose enhancement from scattered radiation due to dental restorative materials used for occlusal and mesio-occlusal-distal (MOD) cavity filling during simulated head and neck radiotherapy.

Methods: We have studied the dose enhancement ratio (DER) of conventional amalgam, high-copper amalgam, and resin composite dental restorative materials at cadaver mandible teeth using 2 therapeutic photon energies of 1.25 MeV (Co-60 gamma ray) and 6 MV (Linac X-ray) for irradiation.

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Background: Adverse effects of breast irradiation have been an important concern given the increased survival of early stage breast cancer (ESBC) patients with more effective treatments. However, there is paucity of data on the utility of Active Breathing Control (ABC) technique for right-sided ESBC patients. In this study, we assessed the incorporation of ABC into adjuvant Radiation Therapy (RT) of right-sided ESBC patients and report our dosimetric results.

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Background: Radiodermatitis is a frequent side effect of breast cancer radiotherapy (RT). Treating radiation oncologist should know the prevention and treatment of every grade of radiodermatitis.

Aims: The aim of this study was to compare the topical corticosteroid and moisturizer usage in breast cancer RT.

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Breast cancer is the most frequent cancer among females and also a leading cause of cancer related mortality worldwide. A multimodality treatment approach may be utilized for optimal management of patients with combinations of surgery, radiation therapy (RT) and systemic treatment. RT composes an integral part of breast conserving treatment, and is typically used after breast conserving surgery to improve local control.

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Background: Infiltration of the breast by leukemic cells is uncommon but may manifest as an oncological emergency requiring prompt management. Extramedullary relapse of T-cell acute lymphoblastic leukemia (T-ALL) within the breast is exceedingly rare and there is paucity of data in the literature regarding this entity. No consensus exists on management of isolated extramedullary breast relapses of T-ALL.

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Introducton: Adjuvant radiotherapy after surgical resection is used for the treatment of patients with brain metastasis. In this study, we assessed the use of adjuvant hypofractionated stereotactic radiotherapy (HFSRT) to the resection cavity for the management of patients with brain metastasis.

Materials And Methods: A total of 28 patients undergoing surgical resection for their brain metastasis were treated using HFSRT to the resection cavity.

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Background And Objective: Colorectal cancer is a major health concern as a very common cancer and a leading cause of cancer-related mortality worldwide. The liver is a very common site of metastatic spread for colorectal cancers, and, while nearly half of the patients develop metastases during the course of their disease, synchronous liver metastases are detected in 15% to 25% of cases. There is no standardized treatment in this setting and no consensus exists on optimal sequencing of multimodality management for rectal cancer with synchronous liver metastases.

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Aims And Background: There is scant data on the utility of repeated radiosurgery for management of locally recurrent brain metastases after upfront stereotactic radiosurgery (SRS). Most studies have used single-fraction SRS for repeated radiosurgery, and the use of fractionated stereotactic radiosurgery (f-SRS) in this setting has been poorly addressed. In this study, we assessed the utility of f-SRS for the management of locally recurrent brain metastases after failed upfront single-fraction SRS and report our single-center experience.

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Objectives: The aim of this study was to investigate the effect of dental implant materials with different physical densities on dose distribution for head and neck cancer radiotherapy planning.

Methods: Titanium (Ti), Titanium alloy (Ti-6Al-4V), Zirconia (Y-TZP), Zirconium oxide (ZrO), Alumina (AlO) and polyetheretherketone (PEEK) dental implant materials were used for determination of implant material effect on dose distribution. Dental implant effect was investigated by using pencil beam convolution (PBC) algorithm of Eclipse treatment planning systems (TPS) and Monte Carlo (MC) simulation technique.

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Background And Objective: Although accounting for a relatively small proportion of all lung cancers, small cell lung cancer (SCLC) remains to be a global health concern with grim prognosis. Radiotherapy (RT) plays a central role in SCLC management either as a curative or palliative therapeutic strategy. There has been considerable progress in RT of SCLC, thanks to improved imaging techniques leading to accurate target localization for precise delivery of RT.

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Purpose: In this study, lung radiotherapy target volumes as well as critical organs such as the lungs, spinal cord, esophagus, and heart doses calculated using pencil beam (PB) and Monte Carlo (MC) algorithm-based treatment planning systems (TPSs) were compared. The main aim was the evaluation of calculated dose differences between the PB and MC algorithms in a highly heterogeneous medium.

Methods: A total of 6 MV photon energy conformal treatment plans were created for a RANDO lung phantom using one PB algorithm-based Precise Plan Release 2.

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Purpose: The aim of this study is to evaluate adaptive radiotherapy (ART) by use of replanning the tumor bed boost with repeated computed tomography (CT) simulation after whole breast irradiation (WBI) for breast cancer patients having clinically evident seroma.

Materials And Methods: Forty-eight patients with clinically evident seroma at the time of planning CT simulation for WBI were included. Two RT treatment plannings were generated for each patient based on the initial CT simulation and tumor bed boost CT simulation to assess seroma and boost target volume (BTV) changes during WBI.

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Purpose: While microsurgical resection plays a central role in the management of ACMs, extensive surgery may be associated with substantial morbidity particularly for tumors in intimate association with critical structures. In this study, we evaluated the use of HFSRT in the management of ACM.

Materials And Methods: A total of 22 patients with ACM were treated using HFSRT.

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Purpose: The aim of this study was to evaluate the outcomes of total skin electron beam therapy (TSEBT) with "translational technique" in the management of mycosis fungoides (MF).

Methods: Between January 1995 and October 2014, 51 patients with MF were treated using TSEBT with translational technique. The total dose was 2800-3600 cGy, de-livered in 7 to 20 fractions.

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Aims: The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife).

Methods: Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique.

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Article Synopsis
  • Glioblastoma (GBM) is a challenging brain tumor with poor prognosis, and this study reviewed the effectiveness of hypofractionated stereotactic radiotherapy (HFSRT) for patients with recurrent GBM.
  • Twenty-eight patients were treated with a total dose of 25 Gy over 5 days, and their outcomes were evaluated based on variables such as age, tumor size, and overall health status.
  • Results indicated that HFSRT is a viable treatment option, with median overall survival of 10.3 months influenced by factors like longer time before recurrence, smaller tumor size, better performance status, and younger age.
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Purpose: This study evaluated the dose distribution and homogeneity of four different types of intensity-modulated radiotherapy (IMRT) in comparison with standard wedged tangential-beam three-dimensional conformal radiotherapy (3DCRT) of the left breast in patients who had undergone lumpectomy.

Materials And Methods: Five radiotherapy treatment plans, including 3DCRT, forward-planned IMRT (for-IMRT), inverse IMRT (inv-IMRT), helical tomotherapy (HT) and volumetric-modulated arc therapy (VMAT), were created for 15 consecutive patients.

Results: All modalities presented similar target coverage.

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