Shoukat H. Khan, Syed Mushtaq Ahmad

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1 IJNM, 18(3): 57-61, 2003 ORIGINAL ARTICLE Whole Body Dose to Radiation Workers at a Tertiary Care Hospital in Kashmir: Analysis and Comparison with Naional Multi-Institutional Pool of Medical Radiation Workers Shoukat H. Khan, Syed Mushtaq Ahmad Department of Nuclear Medicine, Sher-i-Kashmir Institute of Medical Sciences Srinagar, J and K Aretrospective analysis of whole body dose to 109 radiation workers of Sher-i-Kashmir Institute of Medical Sciences, Srinagar, was done for a single block of 5 years from 1995 to The observations were compared with a pool of multi-institutional medical radiation workers of the country. The average annual whole body dose to radiation workers at our institute was showing a rising trend from 1997 ~ and has been much higher than that of medical radiation workers from the multi-institutional pool. During the later half of the block the workers of all the radiation departments of the institute except Radiotharpy had received a higher radiation exposure in comparison to similar workers from the multi-institutional pool. No doubt the annual dose of radiation workers at our institute is within safe limits but there is a rising trend in this dose and the radiation exposure to workers at our institute is well above the national annual average as reflected in the multi- institutional pooled data. The causes of this consistent observation need to be evaluated. Key words: Monitoring, Film badge, Radiation workers, Whole body dose Correspondence to: Dr. Shoukat H. Khan, MD., DRM, Assistant Professor Department of Nuclear Medicine, Sher-i-Kashmir Institute of Medical Sciences P. Bag 27, Soura, Srinagar, J & K Introduction In the present day practice of medicine, the use of ionizing radiations is quite common. Radiation technology is most frequently used for diagnosis, accurate localization and treatment planning. Radiations in the form of X-rays, gamma rays and beta particles have widespread therapeutic applications in a wide variety of diseases, notably cancers. Unsealed radioactive sources like Technetium-99m (Tc-99m), Thallium-201, Indium-lll, Gallium-67 etc., are used extensively for imaging various organs and systems. Radioisotopes like Iodine-131, Strontium-89, Phosphorous-32, Semarium-153, Rehenium-186 etc are frequently used, in treatment of various endocrine disorders, mostly pertaining to thyroid gland and for pain palliation in metastatic cancers of bone(l). Almost all the leading hospitals of the country have mainstream radiation facilities like Radiodiagnosis, Radiotherapy and Nuclear Medicine. Non-conventional radiation departments like Cardiology, Gastroenterology, Immunology and Neurosurgery also use ionizing radiations in some form or the other for diagnosis and treatment. Intraluminal brachythesepy and endovascular radioactive stents are emerging as acceptable alternative treatment modalities in advanced cancers of luminal organs and in coronary artery disease (2, 3). The rapid expansion of radiation technology has resulted in an exponential increase in the quantum of radiation related works and the number of professional radiation workers. The issue of safety standards in radiation work has acquired new dimensions and is a matter of serious concern. International agencies like, International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection(ICRP) have from time to time recommended basic safety standards and prescribed safe limits of radiation exposure to the professional radiation workers and general public (4,5). Atomic Energy Regulatory Board of India (AERB) is the apex national authority concerned with matters of radiological safety and radiation protection (6). The present study was undertaken with the primary objective of ascertaining the overall status of radiation safety at Sher-i-Kashmir Institute of Medical Sciences (SKIMS),

2 Shoukat H. Khan et al Table 1: Diagnostic and therapeutic radiation work done at SKIMS during Radiodiagnosis Radiotherapy Nuclear Medicine Year X-ray CT scans Patients treated Scans Iodine-131 Low-dose Studies with cobalt-60 (TC-99m) uptakes I-131 Therapy x Srinagar as reflected by the whole body dose to its radiation workers during the block of 5 years ftom 1995 to SKIMS is a 600 bedded tertiary care, teaching, university hospital and only one of its kind in the state of Jammu and Kashmir. Radiation facilities available at SKIMS include departments of Radiodiagnosis, Radiotherapy and Nuclear Medicine (Table-1). A total of approximately 2000 CAT scans and 25,000 plain radiographs are performed in the department of Radiodiagnosis annually. The department of Radiotherapy is equipped with two Cobalt-60 teletherapy units. Approximately 700 patients receive radical and palliative radiation therapy annually. Nuclear Medicine department at SKIMS has two gamma cameras (planar and SPECT), a thyroid uptake probe and a radioisotope dose calibrator. The department procures 11.1 GBq (300 mci) of radioactivity in the form of Mo-Tc 99m generator every week. On an average 2500 scan views are performed annually, that include static, dynamic and cardiac SPECT studies. About 30 patients receive Iodine- 131 for thyrotoxicosis every year (Table-1). All the radiation workers at SKIMS are subjected to regular personal whole body dose monitoring by Thermo luminescence dosimeter (TLD, Calcium Sulphate:Dysprosium) since the year 2000, and film badge s earlier. The dosimeters are supplied through Bhabha Atomic Research Centre (BARC), Mumbai. SKIMS has a full time level-iii Radiological Safety Officer. Materials and Methods One hundred and nine radiation workers of SKIMS subjected to personal radiation dose monitoring between 1975 to 1999 were retrospectively included in this study. The study group included 37 radiation workers from the department of Radiodiagnosis, 18 from the department of Radiotherapy, 15 workers ftom the department of Nuclear Medicine and 39 from other departments like Immunology, Cardiology, Gastroenterology and Medical Physics. Whole body dose to all these radiation workers was monitored regularly using a Figure 1: Comparison of radition burden of workers at SKIMS and Multi-institutional pooled data in block years

3 Indian Journal of Nuclear Medicine, Vol. 18, No. 3, September, 2003 Table2: Average block (95-99) dose to radiation workers of various departments of SKIMS Department Average Block (95-99) Dose / Person (msv) film badge dosimeter. AIl the radiation workers wore the film badge at the chest level during their working hours. The film badge dosimeters were regularly sent to personnel monitoring section ofbarc for analysis and report. The records of individual radiation doses were properly maintained for further statistical evaluation. Average annual dose to ~e radiation workers at SKIMS was calculated and compared with multi-institutional average annual dose across the country involving 14,384 to 16,514 medical radiation workers belonging to 1903 to 2238 institutions for the similar period of 5 years ftom 1995 to The average annual radiation dose to workers of various departments at SKIMS was also compared to multi-institutional departmental average annual dose. The average block (95-99) dose of radiation workers in various departments of SKIMS was worked out. Results Range (msv) Radiodiagnosis to Radiotherapy to 4.40 Nuclear Medicine to 4.90 Others to 3.65 The average annual whole body dose to the radiation workers at SKIMS for successive years from 1995 to 1999 (Table 2) though within the prescribed safety limits has shown an intermittent rise, with the maximum dose of 0.99 milli Sieverts (msv) during The average yearly dose among radiation Table 3: Average annual whole body dose per radiation workers Year SKIMS (msv) Multi-institutional Pooled data (msv) (15847 persons /2203 institutions) (16514 persons /2238 institutions) (15769 persons /2092 institutions) (14384 persons /1903 institutions) (15204 persons / 2083 institutions) workers at SKIMS has been on a higher side since 1997 in comparison to the radiation workers from the multi-institutional pool (Fig-I). The maximum average annual dose of 0.99 msv per radiation worker at SKIMS is in excess of the maximum yearly dose of 0.55 msv among radiation workers of multiinstitutional pool (Table 3). The average annual dose among multi-institutional radiation workers has been, more or less a constant level during the years from 1995 to 1999, which is in contrast to the radiation workers at SKIMS. On departmental analysis, the workers of Radiodiagnosis at SKIMS have all along received a dose higher by a factor of 2-3 in comparison to Radiodiagnosis workers from the multi-institutional pool (Table 4). Comparatively the dose to workers of Radiotherapy department at SKIMS was less than that of Radiotherapy workers among the multi-institutional pool of radiation workers (Table 4). The average annual whole body dose to Nuclear Medicine workers of SKIMS when compared to similar workers amongst the multi-institutional pool has been less from 1995 to 1997, however, thereafter a significant rise in the dose was seen in successive years of 1998 and 1999 (Table 4). The average block dose (Table 2) to radiation workers at SKIMS was maximum for radiodiagnosis at 4.80 msv, followed by Nuclear Medicine at 2.33 msv. The lowest dose was seen Figure 2: Histogram comparison of radition burden of workers at SKIMS and Multi-institutional pooled data in block years

4 Shoukat H. Khan et al amongst the workers of department of radiotherapy at 0.44 msv. Discussion The present study shows an overall dose proflle of radiation workers at SKIMS within the prescribed safety limit of 20 msv annually. However, a serious analytical introspection needs to be undertaken to fmd out possible reasons for a higher annual dose with a rising trend among the radiation workers at SKIMS in comparison to others represented in the multi-institutional pool. Comparative analysis of various departments at SKIMS has revealed an annual dose higher by a factor of 2-3 among the staff of Radiodiagnosis department at SKIMS (Table 2). One of the workers of this department crossed the prescribed annual safety limit in 1998 and received 21 msv. These observations regarding the department of Radiodiagnosis at SKIMS are quite disturbing. The average annual whole body dose to the workers of Radiotherapy department at SKIMS is within safe limits and much below the national average of radiotherapy workers represented in the multi-institutional pool. It is pertinent to mention that as of today the Radiotherapy department at SKIMS does not have facilities for brachytherapy. Nuclear Medicine department of SKIMS when compared to the pooled data from other Nuclear Medicine centers of the country had a higher annual dose to its workers from 1997 to 1999 (Table 4). A lower dose to Nuclear Medicine workers at SKIMS during 1995 and 1996 is explainable by the fact that very little scintigraphy work was done in these years as the gamma camera was non-functional. The annual dose and its excess over the multi-institutional average is alarming, considering the fact that the quantum of work and activity handled in Nuclear Medicine department at SKIMS is modest and the department as yet does not administer larger doses of Iodine-131 to patients suffering from metastatic or residual cancer of thyroid gland (Table 4 & Table 5). The whole body radiation dose to workers of other SKIMS department like Gastroenterology, Immunology, Cardiology and Medical Physics is within safe limits at an annual average of less than 0.33 msv. Paradoxically even in these departments that use low level radiations there is an upward trend in the annual whole body dose. The fluctuating and rising levels of average annual dose to the radiation workers at SKIMS are alarming. The results of this analysis presume that personal dosimeters (film badge) Table 4: Average annual whole body dose of radiation workers in various departments Radiodiagnosis Radiotherapy Nuclear Medicine (msv) (msv) (msv) Year SKIMS Multi- SKIMS Multi- SKIMS Multiinstitutional institutional institutional Table 5: Approximate quantity of radionuclidies (GBq) handled in Nuclear Medicine Deptt. of SKIMS and the average annual whole body dose (msv) to workers of Nuclear Medicine during Year I-131 Mo-99 Tc-99m Total Dose (GBq) (GBq) (GBq) (GBq) (msv) x x

5 Indian Journal of Nuclear Medicine, Vol. 18, No. 3, September, 2003 were worn during all the working hours by those monitored, which is too optimistic a situation and these film badges are not stored in radiation area. Conclusion The average annual whole body dose to radiation workers at SKIMS though within safe limits is above the national average. Radiological safety officers together with concerned consultants and technologists will have to find the cause of this observation and evolve a strategy to bring down the exposure according to the well laid principles (7-12). Good work practices among the radiation workers at SKIMS will need to be emphasized and implemented. Regular workshops in co-ordination with national regulatory bodies on radiological safety need to be held apart from other appropriate measures.. Acknowledgement We are thankful to Dr. R.K. Kher, in charge Dose Records and Statistics, Radiological Physics and Advisory Division, BARC. Mumbai fur providing me the multi-institutional data for block We are also thankful to Dr. Wahat H. Andrabi, Radiological Safety Officer, SKIMS, for his help in providing the details of personnel dose monitoring at our Institute. 2. Burt P, O Driscoll R, Notley M et al. Intraluminal irradiation for palliation of lung cancer with high dose rate micro-selectron. Thorax 45:765, Teirstein P, Masullo V, Jani S et ai. Catheter based radio-therapy to inhibit restenosis after coronary stenting. N Engl J Med 336: , ICRP,Recommendations of international commission on Radiological Protection, Report 60, Pergamon press, Oxford: ICRP, Recommendations of international commission on Radiological protection. Publication 26, Pergmon press, New York: AERB safety code no. SC/MED-4: Safety code for Nuclear Medicine Laboratories, AERB, Mumbai, India, Hendee INR, Edwards FM. ALARA and an integrated approach to radiation protection. Seminar Nucl Med 16(2), , Murphy PH. Guidelines of radiation protection. Seminar Nucl Med 16(2), , Nuclear Regulatory Commission: Notices, Instructions and Reports to workers: Inspections. Code of Federal Regulations, Title 10, Part Evans RD. Radiation protection and the staff of Nuclear Medicine departments. Eur J Nucl Med 16, , Basic principals of occupational radiation monitoring. Safety Series no. 84 IAEA, Vohra K.G., Bhatt R.C., Bhuwan Chandra et al. A personnel dosimeter TLD Badge based on CaS04: Dy Teflon TLD discs. Health Physics, 38: 193,1980. References 1. Coursey B.M., Radionuclides for bone palliation. Appl Radiat Isot, ,

Radiation physics and radiation protection. University of Szeged Department of Nuclear Medicine

Radiation physics and radiation protection University of Szeged Department of Nuclear Medicine Radiation doses to the population 1 Radiation doses to the population 2 Sources of radiation 1 Radiation we