CLINICAL STUDY OF RADIO ACTIVE IODINE UPTAKE IN DIFFERENT GOITRE CASES IN CO-RELLATION WITH NORMAL INDIVIDUALS

Aim: to measure the radioactive iodine uptake in different variants of goiter Materials & Methods: subjects with normal levels of T 3,T4 & TSH and no goiter (control group) and examination group which is divided in to three sub groups eu-thyroid goiter, hypo-thyroid goiter and hyper-thyroid goitre cases. Each group is having 10 subjects. All the subjects are females aged 35 yrs±5 and no one is receiving any drugs since 6 weeks just before the beginning of the study. Radioactive iodine uptake is measured by using the bellow formula % uptake = CPM in thyroid –CPM of background activity X CPM standard X 100 CPM standard CPM dose administered Results and Observations: At 2 hrs: in hypo-thyroid cases RAIU is elevated, in hyper-thyroid subjects RAIU uptake is increased and in eu-thyroid subjects the uptake is decreased. At 24 hrs: in hypo-thyroid cases RAIU is decreased, in hyper-thyroid subjects RAIU uptake is increased and in euthyroid subjects the uptake is decreased in comparison with the control group. Conclusion: Radioactive iodine uptake is increased at 2 hrs and decreased at 24 hrs and 48 hrs in hypo-thyroid subjects, P value is significant at 24 and 48 hrs only.


INTRODUCTION
Thyroid gland is a centre of attraction for the biological research. Goitre is the enlargement of thyroid gland. Goitre could be with normal T 3, T 4 and TSH levels in the blood (eu-thyroid), could be with increased T 3, T 4 levels with normal or decreased TSH levels 5 (hyperthyroid) and it could be with decreased T 3, T 4 levels with increased TSH levels (hypothyroid).There are so many tests to study the functioning of thyroid gland like f MRI,PET scan etc.,but radio active uptake of iodine studies along with blood T 3, T 4 assay is considered to be the most sensitive and more reliable than the other tests. In the clinical study we are correlating the uptake of radioactive iodine in eu-thyroid, hypo-thyroid and hyper-thyroid goitre cases with normal individuals.

Aims & Objectives:
To study the radioactive iodine uptake in different variants of goiter in comparison with normal individuals.

MATERIAL & METHODS
All the subjects including examination group and control group are female's only. Average age of the subjects is 30yrs±5. Normal subjects without goitre and with normal plasma T 3 , T 4 and TSH levels are as control group. We have selected 30 cases of goitre as examination group and divided the subjects in to three groups one group is eu-thyroid, second group is hypo-thyroid and the third group is hyperthyroid and each group is consisting of 10 subjects. We have classified the subjects in to eu-thyroid, hypo-thyroid and hyper-thyroid basing on plasma T 3 , T 4 and TSH levels 4 . The subjects were not taking any thyroid medications since 6 weeks just before the test 3 . Blood sample was collected from the subjects in to the test tube during the early hours of the day before breakfast at 7-8 am. Collected blood sample is allowed to clot at room temperature then centrifuged and serum is collected and stored at 2-8 degree centigrade temperature for assay on the same day. 2.1 Radio immune assay (RIA) of T 3 T 4 and TSH: in our study the kits used for RIA of T 3 and T 4 are RIAK -4/4 A and RIAK -5/5, respectively 7 . For TSH estimation Immuno-Radio Metric Assay (IRMA) 1 Kit for Human thyroid stimulating hormone -IRMAK -9 is used. These kits were collected from radio pharmaceuticals operations, board of radiation and isotope technology of navi Mumbai.

Reagents of RIAK -4/4 A:
1. T 3 Standard (lyophilized) 2. Antisera complex (lyophilized) 3. 125 I-T 3 (lyophilized) 4. T 3 free human serum (lyophilized) 5. Control serum A and B (lyophilized) 6. Concentrated assay buffer (solution) 7. Polyethylene glycol (PEG) dry powder Reconstitution of Reagents: the reagents of the T 3 assay kit are reconstituted as follows: 1. Assay Buffer: 100 ml of double distilled water is added to the contents of concentrated buffer vial. This reconstituted assay buffer contains 0.1% Gelatine in 0.14 M THAM (Tris-Hydroxymethyl Amino Methane) buffer, PH adjusted to 8.6. 2. T 3 standard: 5 ml of assay buffer is added to the T 3 standard and gently mixed. The reconstituted standard is 2.4 ng/ ml and called standard A. Other standards are reconstituted as follows: Assay buffer in ml 0.5 1. 3. T 3 Antisera complex: 10 ml of buffer is added to T 3 anti sera complex. 4. 125 I -T 3 : 10 ml of buffer is added and gently mixed. 5. T 3 free serum: 2 ml of doubled distilled water is added. 6. Control serum A&B: 0.5 ml of doubled distilled water & mixed gently. 7. Polyethylene glycol (PEG): PEG powder is transferred to a 125 ml reagent bottle containing 100 ml of 1% (W/V) Nacl .The powder is mixed well till dissolution is obtained. All the reconstituted reagents are stored at 5 0 C, thus stored reagents are stable up to one week.

T 3 ASSAY FLOW CHART
Volumes in micro-liters In thyroiditis 8 trapping function is normal or increased and organification is impaired, in iodine deficiency RAIU is increased .The uptake is increased in hyper-thyroid subjects suggesting hyper functioning of gland. In euthyroid cases the uptake is decreased and it could be because of decompensated dyshormonogenesis or thyroiditis.At 24 hours: in hypo-thyroid cases RAIU at 24 hours is decreased, in hyper-thyroid subjects RAIU uptake is increased and in eu-thyroid subjects the uptake is decreased.At 48 hrs: RAIU uptake is reduced in hypo-thyroid individuals, in hyper-thyroid subjects the uptake is increased but not significantly and in eu-thyroid subjects the uptake is decreased 6 .   1. Radioactive iodine uptake is reduced at 2 hrs, 24 hrs and 48 hrs in eu-thyroid subjects P value in all three cases is significant 2. Radioactive iodine uptake is increased at 2 hrs and decreased at 24 hrs and 48 hrs in hypo-thyroid subjects P value is significant at 24 and 48 hrs only 3. Radioactive iodine uptake is reduced at 2 hrs, 24 hrs and 48 hrs in hyper-thyroid subjects P value is significant in all three cases.