EVALUATING LONG-TERM EXTERNAL DOSES AT SHORT RANGE IN PATIENTS RECEIVING 131I TREATMENT FOR DIFFERENTIATED THYROID CARCINOMA

Öz

Objective: Iodine-131 (131I) treatment offers imaging advantages due to its emission of high-energy gamma radiation, despite concerns being raised regarding radiation safety. Various rules and standards for radiation protection have been established internationally and nationally. Patients undergoing this treatment can present a risk of external radiation exposure to the people around them. The purpose of this study is to measure the radiation dose rates around patients who have undergone treatment and to assess the effects of cumulative doses received by those who have been exposed. Material and Method: The study includes a total of 44 patients who had undergone radioactive iodine therapy for differentiated thyroid cancer and measures their thyroid stimulating hormone (TSH) levels and 24-hour radioiodine uptake. The 131I doses administered to the patients were recorded. Following treatment, external dose rates (EDR) were measured at distances of 30 cm and 1 m from the patients at 0, 4, 24, 48, 72, 144, and 240 h post 131I treatment. Radiation exposure was calculated by considering three scenarios for those accompanying the patient. Result: The study calculated the median TSH values of the 44 patients as 81.74±41.98 mlU/L, while the median of their 24- hour uptake values was determined as 6.39±8.42%. The mean administered treatment dose was 5.28 GBq (±1.3). A correlation was observed between the initial 24-hour measurements and the administered dose. Furthermore, another correlation was found between the measurements taken after the 24th hour and the 24-hour uptake value. The radiation exposure for accompanying individuals was estimated to range between 0.4-1.62 mSv across three scenarios. Conclusion: Patients receiving 131I treatment should be given comprehensive information about the importance of radiation protection after treatment and the precautions to be taken during isolation.

Anahtar Kelimeler

• Radiation safety
• differentiated thyroid carcinoma
• 131I
• external dose rate
• radiation protectio

DİFERANSİYE TİROİD KARSİNOMUNDA 131I TEDAVİSİ ALAN HASTALARDA KISA MESAFEDE UZUN DÖNEM EKSTERNAL DOZUN DEĞERLENDİRİLMESİ

Öz

Amaç: İyot-131 (131I) tedavisi, yüksek enerjili gama radyasyonu yayması nedeniyle görüntüleme avantajları sunmakla birlikte, radyasyon güvenliğine ilişkin endişeleri de artırmaktadır. Radyasyondan korunmaya yönelik uluslararası ve ulusal düzeyde çeşitli kurallar ve standartlar oluşturulmuştur. Bu tedaviyi gören hastalar, etraflarındaki kişilerin dışarıdan radyasyona maruz kalma riski oluşturabilir. Bu çalışmanın amacı tedavi gören hastaların yakınındaki radyasyon doz oranlarını ölçmek ve maruz kalanların aldığı kümülatif dozları değerlendirmektir. Gereç ve Yöntem: Diferansiye tiroid kanseri nedeniyle radyoaktif iyot (RAI) tedavisi gören toplam 44 hasta çalışmaya dahil edildi. Tiroid uyarıcı hormon (TSH) düzeyleri ve 24 saatlik radyoiyot alımları ölçüldü. Hastalara uygulanan RAI dozları kaydedildi. Tedaviyi takiben 131I tedavisinden sonraki 0, 4, 24, 48, 72, 144 ve 240. saatlerde hastalardan 30 cm ve 1 m mesafeden eksternal doz oranları (EDR) ölçüldü. Hastaya eşlik edenlerin radyasyon maruziyetleri üç senaryo dikkate alınarak hesaplandı. Bulgular: 44 hastanın ortanca TSH değeri 81,74±41,98 mlU/L olarak hesaplanırken, 24 saatlik alım değerlerinin ortancası %6,39±8,42 olarak belirlendi. Ortalama uygulanan tedavi dozu 5,28 GBq (±1,3) idi. İlk 24 saatlik ölçümler ile uygulanan doz arasında korelasyon gözlendi. Ayrıca 24. saatten sonra alınan ölçümler ile 24. saatteki alım değeri arasında korelasyon bulundu. Eşlik eden kişilerin radyasyona maruz kalma oranının üç senaryoda 0,4 ila 1,62 mSv arasında olduğu tahmin edildi. Sonuç: RAI tedavisi gören hastalara tedavi sonrasında radyasyondan korunmanın önemi ve izolasyon sırasında alınması gereken önlemler konusunda kapsamlı bilgi verilmelidir.

Anahtar Kelimeler

• Radyasyon güvenliği
• diferansiye tiroid karsinomu
• 131I
• harici doz hızı
• radyasyon koruması

Kaynakça

1. 1. Sartor O, Hoskin P, Bruland OS. Targeted radio-nuclide therapy of skeletal metastases. Cancer Treat Rev 2013;39(1):18-26. [CrossRef] google scholar
2. 2. Parthasarathy KL, Crawford ES. Treatment of thyroid carcinoma: emphasis on high-dose 131I outpatient therapy. J Nucl Med Technol 2002;30(4):165-71; quiz 172-3. google scholar
3. 3. Environment ECD-Gf, Protection C. Radiation Protection 97: Radiation Protection Following Iodine-131 Therapy (exposures Due to Outpatients or Discharged Inpatients): European Communities; 1998. google scholar
4. 4. Ayan A, Dönmez S, Aras F, Günalp B, Kıraç S, Özaslan İA, et al. Radyoaktif madde veya radyonüklid tedavi uygulanmış hastanın tıbbi durumunda değişiklik olması halinde radyasyon güvenliği süreci: Acil tıbbi müdahaleler. Nucl Med Semin 2016;3:168-71. [CrossRef] google scholar
5. 5. Parlak Y, Uysal B, Kıraç FS, Kovan B, Demir M, Ayan A, et al. Radyasyon güvenliği kılavuzu: genel tanımlar ve nükleer tıp uygulamalarında radyasyondan korunma kuralları. Nucl Med Semin 2020;6(2):71-89. [CrossRef] google scholar
6. 6. Mulazimoglu M, Edis N, Tamam MO, Uyanik E, Ozpacaci T. The evaluation of the external dose measurement of the patients treated with radioiodine therapy. Radiat Prot Dosimetry 2010;141(3):233-8. [CrossRef] google scholar
7. 7. Flux GD, Haq M, Chittenden SJ, Buckley S, Hindorf C, Newbold K, et al. A dose-effect correlation for radioiodine ablation in differentiated thyroid cancer. Eur J Nucl Med Mol Imaging 2010;37(2):270-5. [CrossRef] google scholar
8. 8. Barrington SF, Kettle AG, O’Doherty MJ, Wells CP, Somer EJ, Coakley AJ. Radiation dose rates from patients receiving iodine-131 therapy for carcinoma of the thyroid. Eur J Nucl Med 1996;23(2):123-30. Erratum in: Eur J Nucl Med 1997;24(12):1545. [CrossRef] google scholar

9. 9. Li P, Zhang A, Liu Y, Xu C, Tang L, Yuan H, et al. Radioactive Iodine Therapy in Patients with Differentiated Thyroid Cancer: Study of External Dose Rate Attenuation Law and Individualized Patient Management. Thyroid 2019;29(1):93-100. [CrossRef] google scholar
10. 10. Azizmohammadi Z, Tabei F, Shafiei B, Babaei AA, Jukandan SM, Naghshine R, et al. A study of the time of hospital discharge of differentiated thyroid cancer patients after receiving iodine-131 for thyroid remnant ablation treatment. Hell J Nucl Med 2013;16(2):103-6. google scholar
11. 11. Pacilio M, Bianciardi L, Panichelli V, Argiro G, Cipriani C. Management of 131I therapy for thyroid cancer: cumulative dose from in-patients, discharge planning and personnel requirements. Nucl Med Commun 2005;26(7):623-31. [CrossRef] google scholar
12. 12. Demir M, Parlak Y, Cavdar I, Yeyin N, Tanyildizi H, Gümüser G, et al. The evaluation of urine activity and external dose rate from patients receiving radioiodine therapy for thyroid cancer. Radiat Prot Dosimetry 2013;156(1):25-9. [CrossRef] google scholar
13. 13. Ahmadi Jeshvaghane N, Paydar R, Fasaei B, Pakneyat A, Karamloo A, Deevband MR, et al. Criteria for patient release according to external dose rate and residual activity in patients treated with 131I-sodium iodide in Iran. Radiat Prot Dosimetry 2011;147(1-2):264-6. [CrossRef] google scholar
14. 14. Yazdanpanah G, Nematdar M, Talebian H, Shabestani Monfared A. Relationship between body mass index and external exposure in hyperthyroid patients treated with iodine-131. Am J Nucl Med Mol Imaging 2022;12(3):99-105. google scholar
15. 15. Dewji S, Bellamy M, Hertel N, Leggett R, Sherbini S, Saba M, et al. Estimated dose rates to members of the public from external exposure to patients with 131I thyroid treatment. Med Phys 2015;42(4):1851-7. [CrossRef] google scholar
16. 16. Bhatia N, Dhingra VK, Mittal P, Saini S. Radiation safety and external radiation exposure rate of patients receiving I-131 therapy for hyperthyroidism and remnant ablation as outpatient: An institutional experience. World J Nucl Med 2023;22(3):203-7. [CrossRef] google scholar
17. 17. Lahfi Y, Anjak O. Evaluation of the release criteria from hospital of thyroid carcinoma patient treated with 131i. Radiat Prot Dosimetry 2016;171(4):534-8. [CrossRef] google scholar
18. 18. Zhang H, Jiao L, Cui S, Wang L, Tan J, Zhang G, et al. The study of external dose rate and retained body activity of patients receiving 131I therapy for differentiated thyroid carcinoma. Int J Environ Res Public Health 2014;11(10):10991-1003. [CrossRef] google scholar
19. 19. Trubey, D. K. New gamma-ray buildup factor data for point kernel calculations: Ans-6. 4. 3 standard reference data. No. ORNL/RSIC-49. Nuclear Regulatory Commission, Washington, DC (USA). Office of Administration and Resources Management; Oak Ridge National Lab., TN (USA). Radiation Shielding Information Center, 1988. [CrossRef] google scholar
20. 20. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP 2007;37(2-4):1-332. google scholar