The environmental dose measurements of high dose Iodine-131 treated thyroid cancer patients during hospitalization period Nina TUNÇEL  Department of Physics, Science Faculty, Akdeniz University, Antalya, Turkey E-mail : ninatuncel@akdeniz.edu.tr

Introduction Radioiodine mostly 131I is one of the oldest clinical radionuclide types which used widely spread in diagnosis and currently used in the treatment of both thyreotoxicosis and thyroid cancer. Large doses of 131I are administered to ablate residual thyroid tissue and functional metastases from thyroid cancer. Nina TUNÇEL

Introduction The regulations In our country it is obligatory to hospitalize the patients receiving high doses of radioactive iodine, the same as European countries regulations. The limit for hospitalization that Turkey Atomic Energy Organization has defined is 800 MegaBecquerel (MBq). Hospitalization is required for patients receiving doses above this amount. However, the patients whose house conditions are not suitable and who will receive doses <800 MBq can be hospitalized(1). The Radioiodine (RI) (iodine-131, or 131I) activity is supposed to remain , <600 MBq in patients’ bodies or the external measurements received at the abdominal level from 1-m distance is required to be under 30 microSievert per hour (mSv/h) during their discharge(9). Additionally, in ‘protection from radiation guide, 97 Europe’ it was stated that this limit for the residual activity remaining in patient’s body needed to be 600 MBq or the external measurement value received from 1-m distance was required to be <30 mSv/h (2, 3). 1. Official Journal of Republic of Turkey (2000). Number 23999, Article 31. 2. European Commission. Radiation protection following Iodine-131 therapy (exposures due to out-patients or discharged inpatients). Radiation Protection 97 (Luxembourg: Office for Official Publications of the European Communities) (1998). 3. Jorgensen, H. B., Hoilund-Carisen, P. F. and Nielsen, V. E. External dose rates in radioiodine treatment of bening goitre:estimation versus direct measurement: Scand. J. Clin. Lab. I˙nvest. 66(6), 509–516 (2006). Nina TUNÇEL

Therapy Patient with I-131 The patient should be kept at least 2h, and if possible one day in the hospital. In the case of cancer treatment, the patient should generally be hospitalized for several days. In all cases, the dose rate at 1 m from the patient should be down to an acceptable level established by the RPC. Hospitalize: >1100 MBq I-131 Release with restrictions: Treatment of thyrotoxicosis Pain palliation (Sr-89, Sm-153) Lactating women (specified procedures) Release without restrictions: Diagnostic procedures IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8 and 12

IAEA Training Material on Radiation Protection in Nuclear Medicine Room for Iodine Therapy (controlled area) only one patient in the room easily cleanable surfaces and utensils extra lead shields door closed warning sign outside restrictions for visitors decontamination equipment IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

Exposures From Patient Contamination External saliva perspiration breath urine 0.5 0.1 0.06 0.03 mSv/h 1000 MBq I-131 0 0.5 1 2 m IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

IAEA Training Material on Radiation Protection in Nuclear Medicine Contamination Administered activity: 1000 MBq I-131 Excretion Concentration Contamination Saliva <2 MBq/g utensils 2 kBq Perspiration <20 Bq/cm2 surfaces 10 Bq/cm2 Breathing 100 Bq/l air 1 Bq/l Urine < 500 kBq/ml toilet 2 kBq/cm2 Generally larger than the derived limits for contamination given by ICRP (publ 57) IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

IAEA Training Material on Radiation Protection in Nuclear Medicine Restrictions Patient with Iodine-131 This is one example of behaviour restrictions IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

IAEA Training Material on Radiation Protection in Nuclear Medicine Restrictions Patient with Iodine-131 And another one IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

Estimated % of Administered I-131 I-131 Dosimetry NCCHPS

I-131 Dosimetry NCCHPS

IAEA Training Material on Radiation Protection in Nuclear Medicine Isolation Ward Bed shield is positioned Areas are covered with plastic backed absorbent material. King Faisal Specialist Hospital and Research Center, Riyadh IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

IAEA Training Material on Radiation Protection in Nuclear Medicine Discharge of Patient Abdalla Al-Haj IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

IAEA Training Material on Radiation Protection in Nuclear Medicine Monitoring Areas suspected to be contaminated are surveyed. Furniture and telephone sets are surveyed. King Faisal Specialist Hospital and Research Center, Riyadh IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

IAEA Training Material on Radiation Protection in Nuclear Medicine Monitoring Derived limit: 3 Bq/cm2 METHODS wipe testing direct surveying The measurements should be documented The measurements should be documented IAEA Training Material on Radiation Protection in Nuclear Medicine Part 8

Part 12. Protection of the public Radiation protection in nuclear medicine Structural Shielding The absorbed dose is determined by factors such as: source strength; length of exposure; distance from the source; transmission through the protective barrier. Patient with I-131 General public This is an illustration of a situation where extra shielding might be necessary D mSv/h 0.3 mSv/procedure Distance d IAEA Training Material on Radiation Protection in Nuclear Medicine Part 12

Materials and Methods In the fixed activity protocol, a high activity typically 3.7, 5.5 and 7.4 GBq (100, 150 and 200 mCi) I–131 was administered to12 patients. Therapeutic doses of 131I was administered orally in capsule form. Nina TUNÇEL

Materials and Methods In general, the patients remained in isolation for a period of 2–3 days. Patients were confined to the two isolation rooms having walls covered with lead. Each room is designed for two beds which were separated by a lead separator. The special delay tank at hospital ground is designed for radioactive waste disposal. Nina TUNÇEL

Treatment rooms Entrance door Corridor

Each treatment room has its own bath and toilet in room. Nina TUNÇEL

Materials and Methods The beta is often dominant radiation for I-131 treatments, although the associated gamma emission gives rise to exposures to other tissues and even to other individuals. Nina TUNÇEL

Materials and Methods The dose rates were measured at 1 m from the patient's thyroid and abdominal levels at different interval times. The clean and unclean room dose rate measurements were performed at each isolated room. Nina TUNÇEL

Materials and Methods For environment dose measurements the dose rate meter (Inspector Radiation Alert, S. E. International, Inc., USA) was used. Nina TUNÇEL

Therapy with <800 MBq I-131 Discharge of Patient Therapy with <800 MBq I-131 External monitoring 30 mSv/h 0 0.1 0.5 1 m

Results Discharge of Patient mR/h at 1m Day

Results Discharge of Patient mR/h at 1m Day

Results Discharge of Patient mR/h at 1m Day

Results Location The clean room overall 0.43+0.56 The toilet bowl Dose rate + SD (mRh-1) The clean room overall 0.43+0.56 The toilet bowl 1.13+1.51 The pillow 0.03 to 2.12 The unclean room overall 1.49+1.99 4.22+2.20 1.33 to 13 The pillow at unclean room 5.02+4.35 The background level was 0.014mRh-1 in the isolation area. Nina TUNÇEL

Results Location Dose rate + SD (mRh-1) Surrounding rooms 7.06+10.33 1.17+8.84 Service door-corridor 87.75+91.87 32.92+12.98 No Pts. Nina TUNÇEL

Date of survey?

Scanning at 7–10 d after therapy

I would like to thank the nuclear medicine department in Akdeniz University School of Medicine.