Practice and Risk at Medical Facilities in Agency Operations

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1 Practice and Risk at Medical Facilities in Agency Operations Igor Gusev Radiation Protection Unit IAEA International Atomic Energy Agency

2 Outline What is medical radiation exposure? Radiation sources and radiation generators used for medical purposes: Diagnostic and intervention radiology Radiotherapy Nuclear medicine Radioactive contamination Practicalities of individual monitoring and exposure assessment Questions IAEA

3 What is medical radiation exposure? Exposure incurred by patients as part of their own medical or dental diagnosis and treatment by persons, other than occupationally exposed, knowingly while voluntarily helping in support and comfort of patients by volunteers in a program of biomedical research involving their exposure IAEA Safety Fundamentals SS No 120: Medical Exposure IAEA

4 Medical exposures categories Diagnostic radiology Image guided interventional procedures Nuclear medicine Radiation therapy IAEA

Radiation sources and generators used for diagnostic

fluoroscopy, intervention radiology, computer

the required potential to the X Ray tube X Ray tube

are relatively low in most procedures; The X-ray

5 Radiation sources and generators used for diagnostic radiology Diagnostic radiology: radiography, fluoroscopy, intervention radiology, computer tomography (CT) Generator : power circuit supplying the required potential to the X Ray tube X Ray tube producing the X Ray beam Radiation doses to patients are relatively low in most procedures; The X-ray radiation is present when the equipment is powered on. X Ray tubes IAEA

6 msv IAEA Radiation Doses in Radiological Exam. (as multiple of chest x-ray) Relative Dose Received Arm, head,ankle & foot (1) Head & Neck (3) Head CT (10) Thoracic Spine (18) Mammography, Cystography (20) Pelvis (24) Abdomen, Hip, Upper & lower femur (28) Ba Swallow (30) Obsteric abdomen (34) Lumbo-sacral area (43) Cholangiography (52) Lumber Myelography (60) Lower abdomen CT male (72) Upper Abdomen CT (73) Ba Meal (76) Angio-head, Angio-peripheral (80) Urography (87) Angio-abdominal (120) Chest CT (136) Lower Abd. CT fem. (142) Ba enema (154) Lymphan. (180) number of chest x-rays

7 Imaging Method with highest contribution to the average medical radiation exposure (excl. angiography) IV uro. Abdomen LS Ba meal Ba enema CT 2 IAEA

8 Long fluoroscopy times and/or thick body masses Coronary Angioplasty lbs; 63 min FT TIPS placement lb Coronary angioplasty 350 lb; 50 min FT Coronary angioplasty 75 yr woman; 42 min FT IAEA International Atomic Energy Agency

Radiation sources and generators used for radiotherapy External beam therapy X Rays: Megavoltage X

40 to 400kVp Linear accelerators 137-Cs and 60-Co Linear accelerators Heavy charged particles:

in close proximity to the target area for radiotherapy) Radionuclide Half-life Photon Energy (MeV)

26 years 1.17, 1.33 11.0 137 Cs 30.0 years 0.662 5.5 192 Ir 74.2 days 0.136-1.06 (0.38 ave) 2.

9 Radiation sources and generators used for radiotherapy External beam therapy X Rays: Megavoltage X Rays: Telecurie units: Electrons:,. 40 to 400kVp Linear accelerators 137-Cs and 60-Co Linear accelerators Heavy charged particles: Protons from cyclotron, C, Ar Others: Neutrons, pions Brachytherapy (the use of radioactive sources in close proximity to the target area for radiotherapy) Radionuclide Half-life Photon Energy (MeV) Half-value Layer (mm lead) 226 Ra 1600 years (0.83 ave) Rn 3.83 days (0.83 ave) Co 5.26 years 1.17, Cs 30.0 years Ir 74.2 days (0.38 ave) Au 2.7 days I 60.2 days ave Pd 17.0 days ave Radiotherapy sources and generators belong to top danger category IAEA

10 Nuclear Medicine application according to type of Radionuclide Radionuclide Diagnostics Therapy Pure emitter ( ) e.g. ; Tc99m, In111, Ga67, I123 Positron emitters (ß + ) e.g. : F-18, ß - emitters e.g. : I131, Sm153 Pure ß - emitters e.g. : Sr89, Y90, Er169 emitters e.g. : At211, Bi213 IAEA 10

Preparation of radiopharmaceuticals Administration Examination of the

11 Exposure of the Worker Unpacking radioactive material Activity measurements Storage of sources Internal transports of sources Preparation of radiopharmaceuticals Administration Examination of the radioactive patient Care of the radioactive patient Handling of radioactive waste Accidents IAEA 11

12 Contamination of the Worker spills improper administration experimental work with animals emergency surgery of a therapy patient autopsy of a therapy patient IAEA 12

13 To Minimize Contamination Risks - adopt clean operating conditions - adopt good laboratory practices - do not eat, smoke etc - use protective gloves and clothing IAEA 13

14 DECONTAMINATION PROCEDURES Use adsorbent paper on wet spill or wet absorbent paper on dry spill Repetitively swab the area inwards towards the center of the spill Place contaminated paper in a plastic bag or container Monitor the area Repeat the procedure until the exposure rate is below given limits If the decontamination is not successful, mark the contaminated area and classify the room as a controlled area (If not already done) until the contamination is completely removed. IAEA 14

15 Decontamination 120 Remaining activity (%) Tc99m pertechnetate Number of washings IAEA 15

16 Decontamination of Skin If contamination of the skin occurs, immediately the area should be thoroughly washed using mild soap and tepid (not hot) water. Particular care should be paid to cleaning under the fingernails. If this does not bring the contamination to an acceptably low level the procedure should be repeated using a decontaminating detergent. Scrub with a nail brush but take care not to break the skin. IAEA 16

17 DECONTAMINATION OF SKIN Remaining activity (%) Method Substance Tc99m-DTPA Tc99m-MDP Pertechnetate Tc99m-colloid <1 <1 <1 <1 I131-hippuran <1 <1 <1 <1 I131-iodide 8 5 <1 2 Ga67-citrate In111-DTPA <1 <1 <1 < : 90 s in water, 2: 90 s in soap and water, 3: skin lotion and 90 s in soap and water, 4: commercial decontamination substance IAEA 17

18 MONITORING OF THYROID (internal contamination) IAEA 18

19 WHOLE BODY MONITORING (contamination) The gamma camera without collimator can be used IAEA 19

20 Individual monitoring and exposure assessment Individual external doses should be determined by using individual monitoring devices: Thermoluminescent or optically stimulated luminescence Film badges Electronic dosimeters Worn at breast level, between the shoulders and the waist The monitoring period should be one month, and shall not exceed three months. The exchange of dosimeters and report receipt should not exceed three months IAEA 20

21 Personal dosimetry Several personal dosimeters are recommended From: Avoidance of radiation injuries from interventional procedures. ICRP Publication 85 IAEA 21

22 Individual monitoring when a lead apron is used The dosimeter should be worn under the apron for estimating the effective dose The other body areas not protected by the apron will receive higher dose One dosimeter worn under the apron will yield a reasonable estimate of effective dose for most instances In case of high workload (interventional radiology) an additional dosimeter outside the apron should be considered by the RPO IAEA 22

23 Pregnant worker In some circumstances, the exposure is inappropriate and the unborn child may be at increased risk Prenatal doses from most properly done diagnostic procedures present no measurably increased risk of prenatal death, malformation, mental impairment Higher doses such as those from therapeutic procedures can result in significant fetal effects. IAEA 23

24 Termination of pregnancy Termination of pregnancy at fetal doses of less than 100 mgy is NOT justified based upon radiation risk At fetal doses in excess of 100 mgy, there can be fetal damage, the magnitude and type of which is a function of dose and stage of pregnancy In these cases decisions should be based upon individual circumstances IAEA 24

25 Thank you for your attention IAEA

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