ESTIMATION OF HOSPITAL STAY TIME FOR CA-THYROID PATIENTS TREATED WITH RADIOIODINE-131 By Sudipta Saha 1 Dr. Ashoke kumar paul 2 Dr. M. Shakilur rahman 1 Dr. Jharna das 2 Dr. Jasmin ferdous 2 1. Institute of Nuclear Science and Technology, AERE, Savar 2. Center for Nuclear Medicine & Ultrasound, Khulna

Introduction Oral administration of radioiodine (I -131) has been a commonly accepted procedure in nuclear medicine for treatment of hyperthyroid, thyrotoxicosis and thyroid carcinoma patients. I -131 as sodium iodide has been used to treat residual cancerous thyroid tissue and metastatic disease after partial or complete thyroidectomy (surgery). The service is also a regular practice in Center for Nuclear Medicine & Ultrasound, Khulna with the facility of indoor cabin of Khulna medical college hospital.

Aim and Objective The study has been carried out - to assess the risk to the environment from these radioactive patients after radioiodine-131 capsule administration. - to re-estimate the time to stay in hospital after post surgery radioiodine therapy procedures for complete thyroid ablation.

Method Type of Study: Prospective Study Place: Center for Nuclear Medicine & Ultrasound, Khulna Khulna Medical College Hospital Study Period:December, 2011 to April, No. of Patients:20 [Twenty] Measuring Tools:Radiation survey meter (Geiger-Muller Counter)

Method (Cont.) According to the suggested procedure by Society of Nuclear Medicine, Bangladesh* the condition to release the patient from hospital is After 7 days with other following steps. or, the survey meter reading at 1 meter distance from patient is 0.2 mrem/h or 2.0µSv/h. One Physicist and one Physician with an expert Scientific personnel are appointed for regular surveillance as well as to take Gamma counts by Radiation survey meter (Geiger-Muller Counters) for dose measurement. * F. Alam, A. S. M. Moinul Islam and M. A. Karim, Bangladesh J. Nucl. Med., 5(2), pp 39 (2002)

Method (Cont.) In the present proceedings, all the patients are categorized in three ways- (a) Sex (b) Surgical Procedure (c) Radioiodine dose received The below table shows the categorized scenario of 20 patients: Table I: SexSurgical ProceduresDose Received MaleFemale Near Total Sub Total Modified neck resection 75 mci 100 mci 150 mci 200 mci Total20

Method (Cont.) The present study is been carried out using the below pictured survey meters. The energy range countable in these survey meters is 0.45 KeV – 2 MeV.

Results In the demonstrated study, total patients were classified into four groups according to their administered activities. P-75 (1-2) = 75 mci capsule administered patients. P-100 (1-14)= 100 mci capsule administered patients. P-150 (1-3)= 150 mci capsule administered patients. P-200-1= 200 mci capsule administered patients.

Results (Cont.) The Table II, III, IV, V show the real picture of decreasing dose rate of radiation at 1 meter distance from patients for 7 days or until the dose decreased below 0.2 mrem/h. The Figures I, II, III, IV are representing the decreasing character of radiation dose from patients graphically.

Results (Cont.) Table II: The doses from patients received 75 mCi. PatientsSurvey counts from 1m distance in µSv/h Just after administration 24 hrs48 hrs72 hrs96 hrs120 hrs144 hrs P P STDEV

Results (Cont.) Figure-1: The graph shows the nature of decrease of radiation dose from patients received 75 mCi. Y-axis is representing the radiation doses in µSv/h with the change according to time in days on X-axis.

PatientsSurvey counts from 1m distance in µSv/h Just after administration 24 hrs48 hrs72 hrs96 hrs120 hrs144 hrs P P P P P P P P P P P P P P STDEV Results (Cont.) Table III: The doses from patients received 100 mCi.

Results (Cont.) Figure-II: The line graph shows nature of decrease of radiation dose from patients received 100 mCi. Y-axis is representing the radiation doses in µSv/h with the change according to time in days on X-axis.

PatientsSurvey counts from 1m distance in µSv/h Just after administration 24 hrs48 hrs72 hrs96 hrs120 hrs144 hrs P P P STDEV Results (Cont.) Table IV: The doses from patients received 150 mCi

Results (Cont.) Figure-III: The line graph shows nature of decrease of radiation dose from patients received 150 mCi. Y-axis is representing the radiation doses in µSv/h with the change according to time in days on X-axis.

PatientsSurvey counts from 1m distance in µSv/h Just after administration 24 hrs48 hrs72 hrs96 hrs120 hrs144 hrs P Results (Cont.) Table V: The doses from patients received 200 mCi Figure-III: In the line graph Y-axis is representing the radiation doses in µSv/h with the change according to time in days on X-axis. of 200 mCi administered patients.

Patient Categories Standard deviation with Time (%) After Administration 24 hrs48 hrs72 hrs96 hrs120 hrs144 hrs P P P Results (Cont.) Table VI: Table of standard deviation calculation with time.

Results (Cont.) According to this guideline 65% of all patients could be released after 96 h as the dose decreased to the required value and the remaining the patients could be released after 120 hrs with maiden exception.

Discussion Study represents, within first 72 hours more than 80% radioiodine has been washed out from the patient body. This time interval after oral administration of therapeutic capsule becomes very important from the point of view of radiation protection. The patient and his/her attendant must be well motivated to follow the written guidelines for lesser contamination.

Discussion (Cont.) In 5 th day the dose decreases to 0.2 mrem/h at 1 meter distance for about 45% patients and near 0.3 mrem/h came from others with one exception. So on the 4 th day and day after, taking the measure of radiation dose the patient can be identified to be released earlier than 7 days.

Discussion (Cont.) Comparing with other guidelines from different countries, considering the socio-economic condition, literacy level, nature of job and family the criteria to release the patient from hospital can be suggested to re- estimate the isolation time duration from seven days to 72 hrs of capsule administration or the dose in radiation survey meter is 4 µSv/h at one meter distance is recorded.

Discussion (Cont.) Advantages of regular monitoring of these patients using survey meter is - Hospital burden of indoor patients can be minimized. - Financial burden of patient and attendants will be minimized.

Conclusion Monitoring of radiation dose during radiation therapy of Ca-thyroid patients is important to assess time limit for discharge of them. Motivation and good communication of patients and measurement of radiation dose using survey meter in hospital admission time may ensure radiation protection to the public as well.

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