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Vol . 8 No. 3 June 2000  

Therapeutic Nuclear Medicine

Radioiodine Administration

A nuclear medicine physician supervising administration of low-noise radioiodine to a patientInternational rules ratified by BARC permit oral administration of 1-131 below 15 mCi dose on OPD basis for treating hyperthyroidism. This is because no raDIATion related risk enhancement was noted in patients or the exposed public in 1arge cohort studies done all over the world. As a conservative estimate, over 500 patients per year for the last 35 years have been benefited by radio iodine treatment given by DRDO firstly on research and later on no-profit basis. The figure includes both defence personnel and civilians.

RaDIATion-Monitoring & Radio-Protection Backup

Usually the raDIATion dose received by the patient undergoing a nuclear medicine test is so low that no extra
precautions need to be taken. The laboratory staff is also never expected to receive raDIATion dose more
than what is prescribed by the international standards. However, there has been a myth and unrealistic doubt in the public mind regarding safety aspects of nuclear medicine. Studies conducted by DRDO using sensitive instrumentation have gone a long way in establishing public confidence in this regard. Handling large quantities of radioactivity (particularly for therapeutic purposes) and the ever-present possibility of spillage make it mandatory for the Different types of table-top and hand-held dosimeters for detecting radioactive contaminationlaboratory to have staff and hardware necessary to assess exposure to the staff as a routine and handle spillage and contamination, if needed. DRDO is using thermo-luminiscent dosimetry (TLD) batches to monitor personal dose exposure to the staff handling radioactive material. The batches are worn over the chest pocket and wrist to estimate the dose received by the individual over a period of time. TLD is still considered the most sensitive and easy method to estimate personal exposure effective over a wide range and type of raDIATions. Besides, various types of contamination monitors ranging from a pen-sized detector (which is actually kept in pocket for instant use) to hand-detector to fixed detector are available for specific exposure rate ranges.

Whole body raDIATion counter is an important raDIATion protection device to correctly estimate the type and quantity of a radionuclide consumed accidentally. This procedure is a prerequisite for starting efforts to decontaminate the body. DRDO has developed such a devise for internal use several decades back both for protection and experimental purposes. Besides, the device has important use at the time of nuclear accidents.