Search

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.

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.

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.