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Background: The aim of this study is to clarify the critical organs that limit treatment scheme and also evaluate the validity of currently used critical organ threshold values in neuroendocrine tumor (NET) patients, receiving peptide receptor radionuclide therapy (PRRT) with Lutetium-177 (177Lu)-DOTATATE. Thirty-six NET patients (ages 16-73 years) who received 177Lu-DOTATATE treatment were evaluated retrospectively in this study. Dosimetric calculations were made using medical internal radionuclide dose method. For calculation of organ doses, Internal Dose Assessment at Organ Level/Exponential Modelling 1.1 software program was used. Follow-up data were used to determine the organ failure. Results: A total of 141 cycles and mean of 3.91 (±1.33) cycles were applied to the patients. A mean of 691 mCi (±257 mCi) 177Lu-DOTATATE infusion in total and a dose between 70 and 200 mCi per treatment was applied to patients. Seven of 36 patients reached 23 Gy renal dose limit. In these patients, although kidney doses were between 23 and 29 Gy, there was no diminution in renal functions during follow-up. Two of 36 patients reached total bone marrow dose of 2 Gy limit. Bone marrow suppression did not develop in these patients. Conclusion: The critical organs that seem to affect the treatment scheme in PRRT with 177Lu-DOTATATE are kidney and bone marrow. Although there are established threshold levels, derived from radiotherapy experience, more studies are needed to clarify these dose limits in systemic radionuclide therapies such as PRRT.

The one of the aim ofnuclear medicine is diagnosis of an abnormal metabolic activities in targetorgans. In a routine nuclear medicineimaging procedure, a radiopharmaceutical is used. Radiopharmaceutical’sradionuclide part emits gamma radiation. This radiation is dedected by GammaCamera or Single Photon Emission Computed Tomography (SPECT). A computedtomography (CT) device was added to the SPECT(SPECT- CT). To combine anatomicalimages. Image quality of this device is important for accurate diagnosis andtreatment of diseases. By means of quality control tests, performance changesof device are dedected. A various quality control parameters such asuniformity, sensivity, resolution, linearity have been developed for Gammacameras, SPECT. Quality control test results are should be verify by comparing acceptableresults. In this study, quality control tests of SPECT-CT are performed asproposed by the National Electrical Manufacturers Association ( NEMA) and it wasaimed to investigate some correction methods., Nükleer tıbbınamaçlarından biri hedef organlardaki anormal metabolik aktivitelerin tanısıdır.Rutin bir nükleer tıp görüntüleme sürecinde, radyofarmasötik kullanılır.Radyofarmasötiğin radyonüklid kısmı gama radyasyonu yayar. Bu radyasyon GamaKamera veya Tek Foton Emisyon Bilgisayarlı Tomografi (SPECT) tarafından dedekteedilir. Anatomik görüntüleri birleştirmek için SPECT cihazına BilgisayarlıTomografi (BT) cihazı eklenmiştir (SPECT – BT) . Bu cihazın görüntü kalitesidoğru tanı ve hastalıkların tedavisi için önemlidir. Kalite konteol testlerisayesinde, cihazdaki performans değişiklikleri belirlenir. Homojenite,sensivite, rezolüsyon, linearite gibi çeşitli kalite kontrol parameterelerigama kameralar ve SPECT için geliştirilmiştir. Kalite kontrol testi sonuçlarıkabul edilebilir sonuçlarla karşılaştırılarak doğrulanmalıdır. Bu çalışmada,SPECT-CT'nin kalite kontrol testleri National Electrical ManufacturersAssociation (NEMA) tarafından önerildiği gibi yapılmış ve bazı düzeltme yöntemlerininaraştırılması amaçlanmıştır.

Dose calibrators are used to measure the amount of radioactive to be given to the patient. It is necessary to determine the correct dose and measure the amount of radioactive material with the least possible error. To minimize these potential errors, quality control (QA) tests should be carried out periodically according to the United States Nuclear Regulatory Authority (NRC). ATOM LAB 400 (serial number:11070208 ) and 500 (serial number: 15091215) dose calibrators which are actively used in our clinic were used. Our aim is to verify the accuracy of the dose calibrator which needs to be updated by using a recently calibrated dose calibrator. QA tests were performed on both dose calibrators. Test results of the currently certified dose calibrator and ATOM LAB 400 dose calibrator whose certificate will be updated were found to be compatible with each other.The tests performed on both dose calibrators remained with the error limits. Calibration certificate of the ATOM LAB 400 calibrator has been updated in accordance with NRC protocol.

Amac: Doz kalibratorlerinden dogru ve guvenilir sonuc elde etmek yalnizca periyodik kalite kontrol testleri ile saglanir. Tani ve tedavi uygulamalarinin optimizasyonunu saglamak ve hastanin radyasyon guvenligi buyuk olcude doz kalibratore bagli oldugu icin test prosedurlerini dogru olarak gerceklestirmek gerekir. Hastalar ve yontemler: Calismamizda Istanbul Tip Fakultesi Nukleer Tip Ana Bilim Dali’nda bulunan Biodex marka Atom Lab 500 doz kalibratoru kullanilarak kalite kontrol testleri yapildi. Test sonuclari Nukleer Duzenleme Kurulunun (NRC) uygunluk kriterleri kullanilarak degerlendirildi. Bulgular: NRC’ye gore, kalite kontrol testlerinin sonuclari ±%5’lik hata payi icinde bulunmalidir. Bu calismada doz kalibrator kalite kontrol testleri NRC standartlarina gore yapildi ve kabul edilebilir sonuclar elde edildi. Sonuc: Doz kalibratorleri nukleer tip bolumlerinde hastaya verilecek radyoaktif maddenin olcumu icin bir zorunluluktur. Bu nedenle bu cihazlarin kalite kontrolleri hastaya minimum radyasyonun verilmesi acisindan son derece onemlidir.

In stereotactic radiotherapy, high radiation doses were delivered to tumors using small fields in 1-5 fractions. It is very important to make sure accuracy of dose and position of given dose in stereotactic radiotherapy. In this study, dosimetric measurements of small sized brain tumors irradiated in CONE- based linear accelator (linac) and the volumetric arc therapy (VMAT) linac modalities were performed with EBT3 film. 1,2 and 3 cm diameter tumors were virtually created in Cyberknife head and neck phantom. Gafchromic EBT3 film was placed into the phantom to evaluate the accuracy of the doses given. The phantom was irradiated with Gafchromic EBT3 film according to treatment plans created in the treatment planning system of two separate devices for each tumor size. Conformity Index (CI) and Homogeneity Index (HI) were calculated for the quality of created treatment plans. The dose distributions calculated in the film and the TPS were compared. When the CI and HI values were examined, the CI and HI values of the cone-based linac device were close to 1. The EBT3 measurement results indicate that all SRT treatment modalities achieved accurate doses. According to results, if a critical organ, such as the brainstem, is located near the tumor and the situation requires a steep dose gradient, the cone-based linac should be used for SRT therapy. This study has shown that on CONE-based linac or VMAT-based linac devices can be used instead of each other in small-area irradiations.

Amaç: Radyasyonlu ortamda çalışan sağlık personelinin radyas-yon konusundaki bilincini değerlendirmek için bir anket çalışması yapılmıştır. Ankete Radyoterapi ve Radyoloji bölümlerinde çalışan Teknikerler ile bu bölümde okuyan öğrencilerin katılımı sağlanmış-tır. Bu iki grup için elde edilen anket sonuçlarının karşılaştırılması amaçlanmıştır. Materyal ve Metot: Bu çalışma, bölüm, deneyim ve eğitim duru-muna göre değerlendirilmiştir. Çalışma verileri değerlendirilirken tanımlayıcı istatistiksel metotların ( frekans, yüzde) yanı sıra verile-rin meslek, tecrübe ve eğitim düzeyleri ile karşılaştırılmasında fark bulunup bulunmadığı ki-kare testleri kullanılarak araştırılmıştır. Elde edilen verilerin analizinde SPSS 22.0 programı kullanılmış ve P değerinin 0.05’in altında olduğu durum istatiksel anlamlı sonuç-lar olarak değerlendirilmiştir. Bulgular: Anket sonuçlarına göre; Teknikerler, öğrencilerden istatistiksel anlamda daha çok doğru yanıt vermişlerdir. Bu durum aldıkları eğitimin daha kaliteli olması ile açıklanabilir. Bunun ya-nında, teknikerlerin bilgi düzeylerinin tecrübe ile arttığı ancak temel bilgilerin yerinin doldurulamadığı görülmektedir. Sonuç: Hizmet içi ve hizmet dışı olarak radyasyonlu ortamda çalışan sağlık personelinin radyasyon güvenliği ile bilgilendirmeye ihtiyacı vardır. Bu bilgilerin belli aralıklarla yenilenmesi fayda sağlayacaktır. Ayrıca radyasyon ile çalışan personelin zaman za-man mesleki bilinçlendirme eğitim, seminer ve kongrelere katılarak mesleki bilgilerinin güncellenmesi gerektiği görülmektedir., Objective: A survey study was conducted to evaluate the aware-ness of the health personnel working in the radiation environment on radiation. The technicians working in the departments of radio-therapy and radiology and the students studying in this department were included in the survey. The aim of this study was to compare the results of the two groups.Material and Method: This study was evaluated according to department, experience and educational status. In the evaluation of the study data, whether there is any difference between the descrip-tive statistical methods (frequency, percentage) and the comparison of data with occupation, experience and education levels, the chi-square tests were used.SPSS 22.0 program was used in the analy-sis of the data obtained and the value of P value below 0.05 was evaluated as statistically significant results.Results: According to the results of the survey; technicians statis-tically gave more accurate answers than students. This can be explained by the higher quality of the education they received. Besides, it is seen that the level of knowledge of technicians in-creased with experience but basic knowledge could not be re-placed. Conclusion: Personnel working in radiation environments need to be informed about radiation safety. Periodic renewal of knowledge will be beneficial. Moreover, it is seen that the personnel working with radiation should update their professional knowledge from time to time by participating in vocational awareness training, seminars and congresses.

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.

Osteoporosis is the most common metabolic bone disease and can result in devastating physical, psychosocial, and economic consequences. It occurs in women after menopause and affects most elderly. Dual-energy x-ray absorptiometry (DXA) is currently the most widely used method for the measurement of areal Bone Mineral Density (BMD) (g/cm2 ) .DXA is based on the variable absorption of X-ray by the different body components and uses high and low energy X-ray photons. There are two important values in the assessment of the DXA. These values are T-score and Z-score. The T-score is calculated by taking the difference between a patient’s measured BMD with the mean BMD of the young normal population, matched for gender and ethnicity, and then by dividing the difference with the standard deviation (SD) of the BMD of the young normal population. T-score and also Z-score are directly depends on the Bone Mineral Density (BMD). BMD measurements should be made periodically in a patient life. But mostly, it is not possible with the same device. Therefore, in this study, for the quality assurance of bone densitometry devices, we evaluated the BMD results measured in the different Bone Densitometry (DXA) devices using a spine phantom.

Neuroendocrine tumours (NET) are cancers usually observed and arisen in the stomach, intestine, pancreas and breathing system. Recently, radionuclide therapy applications with Lu-177 peptide compound are rapidly growing; especially effective clinical results are obtained in the treatment of well-differentiated and metastatic NET. In this treatment, Lu-177-DOTA, a beta emitter radioisotope in the radiopharmaceutical form, is given to the patient by intravenous way. Lu-177 has also gamma rays apart from beta rays. Gamma rays have 175 keV average energy and these gamma rays should be under the control in terms of radiation protection. In this study, we measured the exposure dose from the Lu-177 patient.