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Prostate cancer patient with I-125 seed implants Cremated at a funeral home Resulted in contamination of retort, processing equipment and surrounding.

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Presentation on theme: "Prostate cancer patient with I-125 seed implants Cremated at a funeral home Resulted in contamination of retort, processing equipment and surrounding."— Presentation transcript:

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2 Prostate cancer patient with I-125 seed implants Cremated at a funeral home Resulted in contamination of retort, processing equipment and surrounding rooms Agreement State required decontamination to very restrictive limits

3 Part 1 – implants 63 sources (seeds) mCi /seed Total: 15.8 mCi Written discharge instructions The Radiation Safety Officer should be notified if the patient is hospitalized, or if death should occur. Part 2 – external beam treatments

4 Temperature: F Duration: 2-3 hours Combustion Air Flow: 2000 – 2500 cfm Cooling Period: 1 hour at cfm Remains: 3-9 lbs (bone fragments) Soft tissue vaporized Bone fragments normally pulverized after cremation. Source: Cremation Association of North America

5 Activity 35 mCi I-125 Dose Rates meter from patient 1.6 mR/hr on contact patients abdomen Source - Journal of Applied Clinical Medical Physics

6 Two instances in NRC jurisdiction 9.8 mCi – cremated with NRC permission 2 mR/hr on contact w/ plastic bag of remains Bkg after placing bag in metal urn 12 mCi – cremated with NRC permission No data regarding dose rates

7 Day (-14): Seeds implanted Day (-3): Patient died Day 0: Clinic notified of death, patient cremated, initial characterization, clinic RSO helps funeral home complete cremation procedures Day 1: State regulator notified, remains transferred, facility characterized Day 2: State inspection and survey Day 6: Follow up surveys – State inspector and clinic RSO Day 7: Chase notified and provides decommissioning proposal and prepares to mobilize

8 Day 6 – Day 73: Funeral Home and State negotiate course of action. Options: Shutdown and decay Decommission – refractory was scheduled for relining regardless of incident Day 73: Funeral Home decides to proceed with decommissioning Day 73 – Day 103: State decides release criteria Day 103 – Day 107: On-site work Day 110: Final Status Report submitted to State Day 131: State confirmatory surveys complete Day 133: Facility released for unrestricted use

9 Therapy Clinic RSO responds Conditions Implant patient ashes in pulverizer 2 nd cremated body (ashes) inside retort 3 rd body in refrigerator ready to cremate Dose Rates w/GM detector 100 mr/hr inside retort 10 mr/hr external to pulverizer 1 mr/hr at retort door

10 Patient remains in plastic bag and plastic transport box – 10 mr/hr contact Remains buried Remains of 2 nd person in plastic bag and plastic transport box – 0.1 mr/hr contact Remains returned to family Activity homogenously dispersed in ashes

11 Some items taken to Clinic for DIS Broom head, brushes, whisk broom, dust pan, leather gloves Clinic makes a commitment to accept all waste from remediation for DIS State approves DIS at clinic

12 Clinic RSO performed dose assessment External dose to operator estimated by dose rate measurements and time-motion study Measurements corrected for energy differences between Cs-137 (cal source) and I-125 Thyroid scan conducted at local hospital – dont know results Total dose was 12 mrem to hand and 0.6 mrem TEDE

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14 Retort and Exhaust Retort (3 x 8) No filters or pollution control equipment Crematory Room (8 x 29) Processing Room (9 x 10) (a walled-off section of the Crematory Room) Office (15 x 15)

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19 State regulations are 25 mrem/yr w/ALARA State would not consider dose modeling or application of NRC default screening values NRC DSV for I-125 is 690,000 dpm/100cm 2 Site-Specific Criteria 20 dpm/100cm 2 removable based on RG 1.86 State not really concerned with total contamination or dose rates Chase implemented criteria of detectability (~1000 dpm/100cm 2 ) as a goal for identifying areas for remediation to mitigate risk of exceeding removable contamination limits

20 Direct Measurements Field Instrument for Detection of Low Energy Radiation (FIDLER) Bicron G5 and LMI 2221 Thin Nal(TI) Scintillation Crystal (5 Dia x thick) Thin Window: Beryllium, (0.010 thick) Energy window set at kev to capture I-125 emission for survey – AND - to capture I-129 emissions for calibration and efficiency determination (~22% efficiency, ~ 700 cpm bkg) Removable Measurements Packard Tri-carb 2800 liquid scintillation counter Single channel 0-80 kev, 78% efficiency

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22 Location Total Activity (dpm/100cm 2 ) Removable Activity (dpm/100cm 2 ) Remediation Method Office Floor 5K0.8K Wet Wipe Prep Table 13K1.4K Wet Wipe Process Room Floor 312K5.6K Scabble, Vacuum Process Room Pulverizer 265K10K Vacuum, Scrubbed, scoured and wiped Retort Room Floor 1.4M60K Vacuum, Scrubbed, scoured and wiped Inside Retort Off Scale 1 mR/hr 24K Vacuumed, dose rate reduced dramatically Hammered Removed 2.5 to 5 of floor liner Process Room Exhaust Duct 3.5K112 Wet Wipe

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25 All smears (except one) < 20 dpm/100cm 2, Direct Measurements up to 1400 dpm/100cm 2 NORM in refractory materials 112 dpm/100cm 2 inside exhaust duct – performed dose assessment to leave in place Not accessible for occupancy <<<<<< DSV Short half-life Ridiculous to even think about remediating State accepted

26 State regulator - conservative release criteria No signs of the SS seed capsules Radioactivity attached to ashes – where there was no ash, there was no radioactivity Significant mixing of ashes between cremations If you get cremated, you will have company for eternity Two cases in NRC jurisdiction – NRC does not view as a concern

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