Browsing by Author "Yeyin N."

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    The evaluation of urine activity and external dose rate from patients receiving radioiodine therapy for thyroid cancer
    (2013) Demir M.; Parlak Y.; Çavdar I.; Yeyin N.; Tanyildizi H.; Gümüşer G.; Sayit E.; Erees S.; Sayman H.
    The aim of this study was to determine the external dose rate of iodine retention as a function of time in the bodies of thyroid cancer patients during their isolation period in the hospital. Urine samples were collected at 6th, 12th, 18th, 24th h and 2nd, 3rd, 4th, 5th d from 83 patients after oral administration of 131I and counted. The external dose rates were also simultaneously determined at the same time points. Then, it was expressed as retained radioiodine body activity versus dose rate. Effective half life calculated from urine sample measurements was found as 18.4±1.8 h within the first 24 h and 64±2.7 h between 48 and 120 h. According to this results, the external dose rate (<20 μSv h-1), which patients could be discharged, was achieved after 48 h for 3700 and 5550 MBq, and after 72 h for 7400 MBq of131I treatments. © The Author 2013. Published by Oxford University Press. All rights reserved.
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    Acceptance Tests and Quality Control of the Positron Emission Tomography (PET) Systems; [Pozitron Emisyon Tomografi (PET) sistemlerinin kalite kontrolü ve kabul Testleri]
    (Galenos Publishing House, 2020) Hacıosmanoğlu T.; Demir M.; Toklu T.; Suna Kıraç F.; İnce M.; Parlak Y.; Kovan B.; Dönmez S.; Ayan A.; Özaslan İ.A.; Hiçürkmez M.; Yeyin N.; Poyraz L.
    Quality control (QC) applications are important for the reliability and accuracy of the results obtained from positron emission tomography (PET) imaging systems in clinical trials. With these applications, exposure of patients and employees to more radiation will be prevented, and it will be possible to detect the systems that lost their performance compared to their installation time. QC applications are grouped as acceptance and reference tests, routine periodic QC tests. PET performance tests standardized by National Electrical Manufacturers Association (NEMA) should be used as acceptance and reference tests. In addition, the performance of the device should be monitored by following these tests at six-month intervals. PET/computerized tomography (CT) manufacturers often recommend routine QC procedures for their equipment and require users to follow these recommendations to a minimum. If standards are not defined for routine QC procedures, it is recommended to comply with the general minimum standards for routine QC that all PET/CT centers must perform. Routine QC protocols, the image quality of the PET system; CT image quality and CT dose of the patient; the accuracy of CT-based attenuation corrections; the accuracy of the CT and PET co-registration should ensure that problems that can interact any of the performance characteristics are identified. Since performing PET/CT scans by equipment that does not comply with their specifications may compromise image quality, interpretation of images and reliability of results, daily QC parameters must be evaluated and necessary corrective procedures must be taken prior to scanning. The tests are carried out using the protocol provided by the manufacturer. © Telif Hakkı 2020 Türkiye Nükleer Tıp Derneği / Nükleer Tıp Seminerleri, Galenos Yayınevi tarafından yayınlanmıştır.
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    Radiation Safety Guide: General Definitions and Radiation Protection Rules in Nuclear Medicine Applications
    (Galenos Publishing House, 2020) Parlak Y.; Uysal B.; Kıraç F.S.; Kovan B.; Demir M.; Ayan A.; Poyraz L.; Özaslan İ.A.; Köseoğlu K.; Yeyin N.; Dönmez S.
    Ionizing radiation which is widely used in the field of medicine and industry, and in scientific studies leaves some or all of its energy to the tissue as it passes through living tissue. It causes known possible harmful effects on living organisms, from low exposure doses to high doses. These are stochastic effects (cancer, mutations) and deterministic effects which are recently named as tissue reactions (such as dermatitis, cataracts). It is important to keep the radiation exposure of the radiation workers and the public as low as possible and to keep within the acceptable dose limits in order to avoid unknown harmful effects. Radiation risks to health are assessed by radiation absorbed dose, dose equivalent and effective doses. In routine daily practices, as low as reasonably achievable dose and as low as reasonably practible dose principles, and also, occupational and public permissible dose limits defined by international and national atomic energy agencies should be complied. Radiation protection rules should be followed to reduce an exposure dose as much as possible while working in the radiation areas. Radiation accidents, transportation of radioactive materials and radioactive waste disposal are important special issues for the protection of environmental health, and compliance with radiation protection rules are necessary. With the development of new targeted radiopharmaceuticals, radionuclide treatments are frequently applied in nuclear medicine clinics, especially in the treatment of malignant diseases. Therefore, radiation protection is an important issue especially for the hospital workers performing procedures to the patients who die shortly after administration of high-dose radionuclide therapy. In this guide, the terms related to radiation will be presented at first, and then, the national and international radiation protection rules in radiation works will be given. © Telif Hakkı 2020 Türkiye Nükleer Tıp Derneği / Nükleer Tıp Seminerleri, Galenos Yayınevi tarafından yayınlanmıştır.