Bayram Demir

Radiation protection for accompanying person and radiation workers in PET/CT

The purposes of the present study are to measure the total radiation doses for the radiation workers and for the accompanying person to the patients in positron emission tomography (PET)/computed tomography (CT) imaging. Urines samples from the patients were collected at 43, 62, 87, 117, 238, 362 min after the 555-MBq (18)flour-fluorodeoxyglucose ((18)F-FDG) injection and activities were measured. Dose rates were recorded using a Geiger-Muller counter and the total radiation doses were measured with using an electronic personnel dosemeter. According to the results here, 18.4 % of (18)F-FDG was excreted in the urine in 117 min after injection. At 117th min after injection, dose rates were determined as 345, 220, 140, 50 and 15 µSv h(-1), at proposed distances. The radiation doses after 117 min were measured as 3.92 mSv at 0.1 m, 2.11 mSv at 0.25 m and 1.08 mSv at 0.5 m. In conclusion, radiation protection will be sufficient within 2 h after (18)F-FDG injection for PET/CT imaging in daily practice.

The Effect of Oblique Electron Beams to the Surface Dose Under the Bolus

The aim of this study is to determine the effect of bolus to the surface dose in oblique electron incidences. Irradiations with 4.5, 6, 7.5, 9, and 12-MeV electron beams were made for the incidence angles of 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees and using 3 different bolus setups: (1) unbolused (no bolus), (2) 5-mm bolus, and (3) 10-mm bolus. A set of EBT gafchromic film pieces placed on the phantom surface was irradiated with a 400-cGy dose at D(max) for each setup. Whereas surface dose increased with increasing incidence degrees in the absence of a bolus, it was seen that there was a large surface dose decreasing in the presence of a bolus with increasing incidence angles. For 60 degrees incidence angle, the relative surface doses with unbolused setup were: 88.10%, 90.06%, 89.35%, 90.25%, and 97.10%; with 5-mm bolus: 66.45%, 81.20%, 99.78%, 124.43%, and 116.07%; and with 10-mm bolus: 22.65%, 45.20%, 55.20%, 65.82%, and 90.27% for 4.5, 6, 7.5, 9, and 12 MeV, respectively. The use of bolus in the treatment of highly oblique surfaces with low-energy electron beams significantly decreases the surface dose.

Verification and uniformity control of doses for 90 Sr/ 90 Y intravascular brachytherapy sources using radiochromic film dosimetry

Intravascular brachytherapy (IVBT) is a useful treatment modality for the recurrence of in-stent restenosis following drug-eluting stents (DES) or IVBT failure. The objective of this study was to measure the dose rate of 90Sr/90Y IVBT sources for comparison with that given by the manufacturer and to control the dose uniformities of these sources along the source axis. The dose rates of 90Sr/90Y beta sources were measured with a radiochromic film in a custom-made phantom. The films for calibration were irradiated using 60Co photon beams. The results for the three sources were 4.5%, 2.3%, and 3.5% higher than the corresponding certificate values. Maximum and minimum of the dose rates varied within ±10% of those at source center; and maximum dose discrepancy for the first 90Sr/90Y source train was 8.2%; for the second source train, 7.1%; and for the third source train, 5.1%. Our study showed that the dose rates given by the manufacturer for the three 90Sr/90Y IVBT sources were reliable and dose uniformities were within ±10% along two thirds of the treatment length.

Depth Dose Characteristics of Electron Beams at Extended SSDS.

The purpec: of this study is to investigate the behaviour of the percent depth dose curves (%DD) and surface doses of electronbeams at extended Source-to Surface Distances (SSDS). A (GE) Saturne 42 linear accelerator was used in this study, which produces dual photon energies of 6 and 15 MV as well as eight electron energies ranging between 4.5 and 21 MeV. The % Depth Dose curves were geneated with water scanning equipment at 6, 9, and 15 MeV for 4x4 cm(2) and 20x20 cm(2) field sizes at SSDS of 100 cm, 108 cm, and 115 cm. According to the measurements from surface to the depth of dose maximum the surface dose increased for all of the electron energies studied at extended SSDS for small field sizes. On the other hand for larger field sizes the surface doses decreased at extended SSDS. It was also observed that the increase in the surface dose diminished as the field size approached to 10x10cm(2) then the surface dose started decreasing at extended SSDS as the field sizes increased. Extended SSDS have no observable effect on the tail portion of the depth dose curves.

Neutron production cross–section calculations for some gamma and proton induced reactions on 89Y

Neutron moderation for nuclear applications has an undeniable importance. To be able to moderate neutrons, one of the important step is to choose the convenient material. The material’s response for different type of nuclear reactions, define its possibility and availability for using as a neutron moderator material. The cross–section data of a reaction, which could be expressed as the probability of a reactions occurrence, could provide many benefits in the cases of the experimental difficulties or unsuitable conditions. For such cases, theoretical calculations obtained via verified methods are highly acceptable. In this study, 89Y, which is a neutron moderator material used in nuclear reactors, has been investigated and neutron production cross–section calculations for some gamma and proton induced reactions on 89Y have been completed in the energy interval of 6–772 MeV with two most known and accepted calculation codes, TALYS 1.8 and EMPIRE 3.2. The Two Component Exciton and Exciton models have been used within the codes, respectively. Obtained results by using both code’s mentioned models and exist experimental data reached from EXFOR database have been compared with each other.Neutron moderation for nuclear applications has an undeniable importance. To be able to moderate neutrons, one of the important step is to choose the convenient material. The material’s response for different type of nuclear reactions, define its possibility and availability for using as a neutron moderator material. The cross–section data of a reaction, which could be expressed as the probability of a reactions occurrence, could provide many benefits in the cases of the experimental difficulties or unsuitable conditions. For such cases, theoretical calculations obtained via verified methods are highly acceptable. In this study, 89Y, which is a neutron moderator material used in nuclear reactors, has been investigated and neutron production cross–section calculations for some gamma and proton induced reactions on 89Y have been completed in the energy interval of 6–772 MeV with two most known and accepted calculation codes, TALYS 1.8 and EMPIRE 3.2. The Two Component Exciton and Exciton models have been us...

Nurse exposure doses resulted from bone scintigraphy patient

Bone scintigraphy is used for displaying the radiologic undiagnosed bone lesions in nuclear medicine. It’s general indications are researching bone metastases, detection of radiographically occult fractures, staging and follow-up in primary bone tumors, diagnosis of paget’s disease, investigation of loosening and infection in orthopedic implants. It is applied with using 99mTc labeled radiopharmaceuticals (e.g 99m Tc MDP,99mTc HEDP and 99mTc HMDP). 20 -25 mCi IV radiotracer was injected into vein and radiotracer emits gamma radiation. Patient waits in isolated room for about 3 hours then a gamma camera scans radiation area and creates an image. When some patient’s situation is not good, patients are hospitalized until the scanning because of patients’ close contact care need. In this study, measurements were taken from ten patients using Geiger Muller counter. After these measurements, we calculated nurse’s exposure radiations from patient’s routine treatment, examination and emergency station.

Medikal fizikçilerin eğitimi, görev ve sorumlulukları

Due to the late onset of symptoms, Klatskin tumors or hilar cholangiocarcinoma are usually diagnosed late and long-term life expectancy is very low. In this case, an 83-year-old female patient with diagnosis of obesity and depression was admitted to Family Medicine Outpatient Clinic in Duzce University Medical Faculty because of abdominal pain and nausea ongoing for two days. In hepatobiliary ultrasound examination made in Family Medicine Clinic, gallbladder diameter was 50 mm and bile duct was seen distended to 14 mm. With these findings the patient was assessed by Infectious Diseases and Gastroenterology Clinic. She was directed outside cholangiopancreatography (ERCP). After ERCP clinical situation is further aggravated by developed bacteremia. Due to the late onset of symptoms of the disease, as in our case, and developing bacteremic infections, the disease has resulted in a rapid mortality. In this case, it has been evaluated that table of bacteremic infection superimposed invasive medical procedures resulted to severe prognosis and increases the mortality in elderly patient with Klatskin tumor

Production cross–section calculations of medical 32P, 117Sn, 153Sm and 186,188Re radionuclides used in bone pain palliation treatment

Abstract In this study, production cross–section calculations of 32P, 117Sn, 153Sm and 186,188Re radionuclides used in bone pain palliation treatment produced by 30Si(d,γ)32P, 118Sn(γ,n)117Sn, 116Sn(n,γ)117Sn, 150Nd(α,n)153Sm, 154Sm(n,2n)153Sm, 152Sm(n,γ)153Sm, 186W(d,2n)186Re, 187Re(γ,n)186Re, 185Re(n,γ)186Re and 187Re(n,γ)188Re reactions have been investigated in the different incident energy range of 0.003–34 MeV. Two-component exciton and generalised superfluid models of the TALYS 1.6 and exciton and generalised superfluid models of the EMPIRE 3.1 computer codes have been used to pre-equilibrium (PEQ) reaction calculations. The calculated production cross–section results have been compared with available experimental results existing in the experimental nuclear reaction database (EXFOR). Except the 118Sn(γ,n)117Sn, 150Nd(α,n)153Sm and 185Re(n,γ)186Re reactions, the two-component exciton model calculations of TALYS 1.6 code exhibit generally good agreement with the experimental measurements for all reactions used in this present study.