Dinamika izločanja radioaktivnega joda z urinom med zdravljenjem benignih bolezni ščitnice z I-131

Beguš, Urša (author), Simončič, Urban (mentor), Bajuk-Studen, Katica (comentor), Tomše, Petra (comentor)

Za zdravljenje hipertiroze ob različnih benignih obolenjih ščitnice je v klinični praksi že dolgo uveljavljena terapija z I-131, ki z izsevanjem beta žarkov selektivno uničuje hiperfunkcijsko tkivo ščitnice, hkrati pa oddaja tudi žarke gama. Med terapijo se del aplicirane aktivnosti I-131 izloči z urinom, kar lahko predstavlja sevalno tveganje za osebje in okolico. Zato je pri uporabi radioizotopov potrebno posebno pozornost nameniti varstvu pred ionizirajočimi sevanji in preprečevanju kontaminacije ljudi in okolice. Za namen preučevanja izločanja I-131 z urinom pri bolnikih z različnimi benignimi boleznimi ščitnice smo na hospitalnem oddelku na Kliniki za nuklearno medicino v Univerzitetnem kliničnem centru Ljubljana izvedli prospektivno klinično raziskavo. V raziskavo smo vključili 34 bolnikov s hipertirozo zaradi diseminiranega ali lokaliziranega avtonomnega tkiva v ščitnici, bazedovke ali zaradi obremenitve z jodom. Izvedli smo meritve aktivnosti vzorcev urina, ki so jih bolniki oddali 2 in 4 ure po aplikaciji I-131 ter ob času njihovega odpusta iz bolnišnice. Gama števec, na katerem smo izvajali meritve, smo predhodno kalibrirali. Preverili smo, kako se pri bolnikih po aplikaciji I-131 s časom spreminja aktivnost v zaporednih vzorcih urina in iz meritev ocenili spodnjo mejo deleža izločene aktivnosti I 131 s 3 vzorci urina. Rezultate smo primerjali med bolniki z različnimi benignimi obolenji. Poleg tega smo z izračunom efektivnega razpolovnega časa I-131 preverili, ali med bolniki z različnimi diagnozami prihaja do razlik v hitrosti izločanja I-131 z urinom, in kateri klinični parametri bi lahko vplivali na izločanje I 131. Rezultati naše raziskave kažejo, da so med bolniki z različnimi diagnozami opazne razlike v izločanju I-131 z urinom, pri čemer so na izločanje vplivali tudi klinični parametri. Za učinkovito izvajanje ukrepov varstva pred sevanji je zato zelo pomembno upoštevati diagnozo in klinične značilnosti bolnikov. Naše ugotovitve lahko izboljšajo oskrbo bolnikov z zagotavljanjem natančnejših smernic za varstvo pred sevanjem, ki bodo prispevale k zmanjšanju izpostavljenosti sevanju tako bolnikov kot tudi tistih okoli njih.

• Language: Slovenian
• Keywords: ščitnica, hipertiroza, bazedovka, avtonomno tkivo, I-131, izločanje I-131 z urinom, aktivnost urina, efektivni razpolovni čas, varstvo pred sevanji
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2023
• PID: 20.500.12556/RUL-151650
• COBISS.SI-ID: 167334147
• Publication date in RUL: 14.10.2023

Secondary language

• Language: English
• Title: Urinary Excretion Rate of I-131 During Treatment of Benign Thyroid Diseases

Abstract

The use of I-131 is an effective treatment for benign thyroid disease. It selectively destroys hyperfunctioning thyroid tissue by emission of beta radiation, and simultaneously emits gamma radiation. However, during treatment, the significant excretion of the administered activity in the urine poses a radiation risk to individuals and the environment. Therefore, appropriate radiation safety protocols must be followed when treating patients to prevent potential contamination. We performed a study at the Department of nuclear medicine at the University medical centre Ljubljana aimed to investigate the urinary I-131 excretion in patients with benign thyroid diseases during patients’ isolation period in hospital. We performed a study in 34 hospitalized patients with hyperthyroidism due to thyroid autonomy, Graves’ disease, or iodine-induced hyperthyroidism. Urine samples were collected 2 and 4 hours after oral administration of I-131 and at the time of patient discharge from the hospital. The activity of urine samples was measured with a gamma counter that was previously calibrated. We investigated the urinary excretion of I-131 in consecutive urine samples and estimated the lower limit of the fraction of activity excreted in three urine samples. We compared the results from patients with different benign conditions. Furthermore, we calculated the effective half-life of I-131 to ascertain whether notable variations exist in the rate of urinary I-131 excretion among patients with different diagnoses. Patients with different benign conditions exhibit diverse clinical characteristics, hence we also examined the impact of these features on the excretion of I-131. Significant differences in urinary I-131 excretion were observed among patients with different diagnoses, with the excretion also being influenced by clinical parameters. To implement radiation protection measures for patients undergoing I-131 therapy, it is crucial to consider the diagnosis and clinical characteristics of the patients, which have a significant impact on I-131 excretion. Our findings about urinary I-131 excretion may improve patient care by providing more accurate radiation safety guidelines. These will contribute to lower radiation exposure to themselves and those around them.

• Keywords: thyroid, hyperthyroidism, Graves' disease, autonomously functioning thyroid nodule, I-131, urinary I-131 excretion, urine activity, effective half-life, radiation protection