ML19116A137
| ML19116A137 | |
| Person / Time | |
|---|---|
| Issue date: | 04/03/2019 |
| From: | Donna-Beth Howe NRC/NMSS/DMSST/MSEB |
| To: | |
| Howe, Donna-Beth | |
| References | |
| Download: ML19116A137 (17) | |
Text
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Status of Medical Events FY 2018 Donna-Beth Howe, Ph.D.
Medical Radiation Safety Team April 3, 2019 Medical Events The dose threshold for diagnostic events precludes reportable events most years.
Each year, there are approximately 150,000 therapeutic procedures performed utilizing radioactive materials.
2 Medical Events FY 2013 - 2015
- 43 Medical events reported - FY 2013
- 46 Medical events reported - FY 2014
- 57 Medical events reported - FY 2015 FY13 FY14 FY15 35.200 0 1
3 35.300 2 3 8
35.400 15 5 9 (10*)
35.600 10 10 17 35.1000 16 27 20 (30)
- The total number of patients involved if greater than the number of reports 3
Medical Events FY 2016 - 2018
- 50 Medical events reported - FY 2016
- 43 Medical events reported - FY 2016
- 48 Medical events reported - FY 2018 FY16 FY17 FY18 35.200 4
0 0 35.300 4 4 2 35.400 6 (18) 7 11 (13) 35.600 6 8 (14) 10 35.1000 30 24 25 (26) 4
2 Medical Events 2018 35.300 Medical events 2
Iodine-131 MIBG 1 Radium-223 1 5
35.300 Medical Events Iodine-131 MIBG 1
- 50,000 to 12,000 cGy skin dose to 15 cm²
- Patient was disconnected from infusion pump at Spiros connection to use restroom.
- At end of procedure, high activity of I-131 on patients clothing and bed linen.
- Two days later, patient reported discomfort and reddening of skin on upper right thigh erythematous lesion to desquamation the next day.
6*
35.300 Medical Events Iodine-131 MIBG (cont.)
- 50,000 to 120,000 cGy skin dose to 15 cm²
- Did not decontaminate patient until signs of erythema.
- Will only disconnect patient if medical emergency.
- Will use adsorbent pads under administration line.
- Will develop patient specific decontamination procedures.
7 8
Ra-223 dichloride 1
- Administered 176.1 µCi instead of 180 µCi
- Signed written directive called for oral administration
- Technologist administered intravenous
- Will implement new written directive
- Review current policy and procedures with staff 35.300 Medical Events
3 Medical Events 2018 35.400 Medical events 13 (15)
Eye Plaque 1 Unknown procedure 1 Prostate 9 (11)
One licensee, 3 reports 3 (5)
Human error 2
Wrong site 1 Larger than pre-plan or swelling 2 9
35.400 Medical Events Eye Plaque 1
- Prescribed 8,600 cGy - received 6,500 cGy
- Used new model of eye plaque that differed from old model
- Isodose curves differed from brachytherapy plan.
- Dose was deeper than expected 10 35.400 Medical Events Unknown Procedure 1
- 70% of the intended dose was delivered 11 35.400 Medical Events Prostate 9 (11)
One licensee, 3 separate reports, 5 patients
- Report 1 - First patient prescribed 14,000 cGy, but administered 8,990 cGy - 62% of prescribed dose
- No root cause, but attributed to human error
- Some seeds may have migrated post-implant
- Performed historical review after inspection
- Second Patient prescribed 14,500 cGy, but received 19,200 cGy - 132% of the prescribed dose
- Third Patient prescribed 14,500 cGy, but received 18,900 cGy - 130% of the prescribed dose 12
4 35.400 Medical Events One licensee, 3 separate reports, 5 patients (cont.)
- Report 2 - Patient prescribed 14,500 cGy, but received 10,500 cGy - 72.4% of the prescribed dose
- Report 3 - Patient prescribed 14,500 cGy, but received 7,000 cGy - 48% of the prescribed dose 13 35.400 Medical Events
- Patient prescribed 11,000 cGy, but received 5,815 cGy - 53% of dose
- Partial seed strand implanted in the bladder
- Removed errant seeds immediately with cystoscopy
- Attributed to human error
- Corrective actions include:
- New written procedure
- Use of more needles, more seeds, and less aggressive sparing of the urethra
- Stop using pre-loaded stranded seeds, so improperly implanted seeds can be individually 14 35.400 Medical Events
- Patient intended 10,800 cGy, but 50% of prostate received no dose
- Ultrasound volume of prostate was smaller on ultrasound pre-implant scan than CT post-implant scan
- Real-time implantation with ultrasound did not permit potential visualization errors
- Attributed to human error
- Corrective actions include:
- Additional training to personnel and improved supervision
- Terminate the seed implant program due to low patient volume 15 35.400 Medical Events
- Patient prescribed 11,000 cGy, but received 6,215 cGy - 56.5% of dose
- Attributed to human error
- Improve imaging techniques
- Patient prescribed 14,400 cGy, but received only 73% of dose
- Attributed to 18% increase in prostate size compared to pre-plan
- Planned intentional cooler coverage near rectum
- Additional training to personnel 16
5 35.400 Medical Events
- Patient intended 12,500 cGy, but received 1,000 cGy 12.5% of dose (Pd-103 seeds)
- Used Foley catheter but inflated balloon in prostate urethra instead of bladder
- 32 of 54 seeds placed outside prostate and 3 seeds could not be seen
- Expect risk of radiation damage to rectum and surrounding tissue
- Failed to locate Foley catheter compounded by using magnification factor of ultrasound device that did not give full view of relevant anatomy 17*
35.400 Medical Events
- Patient intended 12,500 cGy, but received 1,000 cGy 12.5% of dose (Pd-103 seeds) [cont.]
- Physician and medical physicist will audibly concur on image quality before preceding
- Manufacturer reset new default magnification value that will initial view of relevant prostate anatomy
- Once first seed is implanted, fluoroscopic image will be used to verify relative location of seed and Foley catheter is where it is expected to be 18 35.400 Medical Events
- Patient prescribed 12,500 cGy, but received 9,670 cGy - 77% of dose (Pd-103 seeds)
- Three seeds from one needle did not remain in place
- Contributing factors:
- AUs preference for peripheral loading
- Potential rotation of the prostate during needle insertion
- Pressure effects from using hydrogel to separate prostate from rectum
- Corrective actions:
- No longer implant needle between urethra and rectum - will use two needles offset on axis
- Use stabilized needles during surgery 19 Medical Events 2018 35.600 Medical events 10 HDR
- Skin 1
- Breast 2
- Gynecological 7 Device malfunction 2 Wrong site 3 Human mistake 2 20
6 35.600 HDR Events Skin 1
- Patient prescribed 8 fractions of 500 cGy each to temple area, but received 350 cGy on first 2 fractions
- First physicist used incorrect setup - forgot to use accuform - second physicist used correct setup
- Wrong position - gap between treatment device and patients skin 21 35.600 HDR Events Skin (cont.)
- Lack of policy for custom immobilization devices for skin treatment
- Therapist present at first treatment and any time there is a new physicist
- Photograph set up with and without patient to show accuform
- Barcode scanning to track custom set up devices 22*
35.600 HDR Events Breast 2
- Wrong site - 1,200 cGy to lateral breast skin
- Patient contacted oncologist because of skin reaction
- Physicist used tip end instead of connector end in treatment plan
- Corrective actions:
Additional training to personnel 23 35.600 HDR Events Breast 2
- Wrong site - 1 cc volume of skin received 850 cGy instead of intended 256 cGy
- Savi applicator - struts 2 and 6 mislabeled - changed orientation of the applicator - direction of radiation
- Corrective actions:
Second physicist to independently verify catheter struts in treatment plan.
HDR review checklist - verify digitization of struts in treatment plan Add HDR plan review to monthly audit Additional training to personnel 24
7 35.600 HDR Events Gynecological 7
- Device malfunction
- Patient to receive 1,500 cGy during 3 fractions in 13 dwell points
- HDR unit malfunctioned at dwell point 9
- Treatment adjusted after repair of the HDR unit 25 35.600 HDR Events
- Device malfunction
- Device failed to fully retract at completion of treatment fraction
- Dose of 100 cGY to patient thigh - source was 5 cm from cylinder guide tube connector
- Source wire was bent near source
- Delay in removing source from vicinity of patient and reporting the event to RSO 26 35.600 HDR Events
- Catheter movement - connector locking nut too loose, which allowed catheter to slide out
- Event discovered by skin reaction progressed to moist desquamation
- Dose to skin of 5,154 to 8,555 cGy
- Corrective action:
Retrain medical staff and AU AU will double check all connections and placement before and after each treatment Purchased new cylinder with new design 27 35.600 HDR Events Prescribed 6 fractions of 350 cGy each - first fraction received 2,100 cGy
- Total treatment time incorrectly entered into treatment planning system
- Human error and poor decision making - started first treatment after hours - second physicist not available
- Corrective actions:
Second physicist has to independently verify treatment plan Physicist to check that plan was exported correctly to the treatment console 28
8 35.600 HDR Events Wrong Site - 587 cGy dose to small intestine and bowel instead of 220 cGy
- Patients pelvis had extensive damage from uterine cancer
- Two dwell positions shifted to deliver dose to non-targeted small intestine/bowel in first of 3 fractions
- Treatment plan modified for next 2 fractions
- Licensee thought not reportable - 10 CFR 35.3045(a)(1) and (3); NRC determined reportable - 10 CFR 35.3045(a)(1)(iii) and (a)(3) 29 35.600 HDR Events Wrong site - 5.5 cm outside the treatment site received 500 cGy in 0.5 cm volume
- Channel 12 digitized twice with no digitization of Channel 13 (Channel 13 digitization included in Channel 12 with no dwell positions for 13)
- Treatment plan displayed expected dose distribution to critical organs and tumor and no dwell positions for Channel 13
- Physician approved the plan 30*
35.600 HDR Events Wrong site - 5.5 cm outside the treatment site received 500 cGy in 0.5 cm volume (cont.)
- Patient discomfort (full bladder)
- Physicist rushed to complete the plan and export to treatment console - error overlooked
- Corrective action:
Second check by physicist that did not prepare the plan Each channel will be carefully reviewed Patient not brought to treatment area until plan has been checked and exported to console 31 35.600 HDR Events Wrong site - 100 cGy outside treatment site Prescribed 1,890 cGy, but received 1,675 cGy
- In first of three fractions digitize the catheter as linear instead of as a single curved catheter
- Physicist failed to recognize the incorrectly reconstructed catheter shape in planning software
- Treatment length of 15.7 cm instead of 9 cm 32*
9 35.600 HDR Events (cont.)
Wrong site - 100 cGy outside treatment site (cont.)
- Discovered on second fraction
- Treatment plan was not enlarged so physicist could not see the dwell points overlapping
- Corrective actions:
Enlarge each treatment plan in which the physicist signs off Use of a formalized check list 33 Medical Events 2018 35.1000 Medical events 25 Perfexion 1 Intervascular Brachytherapy 1 Radioactive seed localization 1 Y-90 Microspheres 22 Unidentified 2 Therasphere 13 SirSphere 7
34 35.1000 Medical Events Perfexion 1
- Device malfunctioned
- Device recorded an error and backup power was low, so the sources were returned to the shielded position
- One-third of prescribed dose delivered 35 Intravascular Brachytherapy 1
- First extra long delivery catheter - source could not get to treatment site and retracted safely to unit
- Second extra long treatment catheter - source still could not get to treatment site but source could not be returned to IVB unit; all catheters removed
- Hydraulic return mechanism failed to return source.
- No dose to treatment site and 39 cGy to surrounding tissue
- Deformation of delivery catheter confirmed root cause 36 35.1000 Medical Events
10 Radioactive seed localization 1
- Expected dose 12 cGy to tissue, but patient received 99 cGy to tissue
- Seed implanted and scheduled for removal 6 days later
- Insurance company rescinded approval after seed was implanted and required 3 medical opinions
- Surgery performed approximately 64 days after implant 37 35.1000 Medical Events Y-90 Microspheres 25 Unknown 2
38 35.1000 Medical Events 35.1000 Unknown Y-90 Events Unknown 2
- Prescribed 13,400 cGy to a segment of the liver, but received 10,300 cGy - 77% of intended dose
- Patient received 60% of prescribed dose 39 Y-90 Microspheres 25 Therasphere 13 (14)
- Overdose 1
- Catheter/Obstruction 8
- Bubbles 2
- Backflow to contrast 1
- Human mistake 1
40 35.1000 Medical Events
11 35.1000 Y-90 Therasphere Events Overdose
- Prescribed 13,600 cGy, but received 29,400 cGy
- Picked up wrong dosage, measured and compared activity to shipping box information and not the written directive
- Shipping box was for next weeks patient
- Post administration calculations identified the medical event
- Will add a dose verification step in interventional radiology 41 35.1000 Y-90 Therasphere Events Dose in Waste Jar
- Prescribed 12,000 cGy administered 1,770 cGy -
liver volume - 14% of intended dose
- Licensee thought equipment did not function as designed
- Most of the dosage was in the waste jar
- Manufacturer could not determine root cause 42 35.1000 Y-90 Therasphere Events
- Two patients received less dose than prescribed
- First patient prescribed 72.6 mCi, but received 15 mCi. Inspector thought expansion tubing resulted in turbulent flow triggering suspension issues
- Second patient prescribed 72 mCi, but received 36.75 mCi - Inspector thought lack of adequate agitation prior to administration or issues with quality/sizing of microspheres
- Extension tubing no longer used
- Manufacturer supported Inspectors findings 43 35.1000 Y-90 Therasphere Events
- Prescribed activity 122 mCi - received 46 mCi - 38%
of intended activity
- From device components sent to manufacturer no cause for the blockage was determined
- Obstruction/blockage located in microcatheter -
obstruction in the outlet tubing at the E junction
- Manufacturer recommended handling microcatheters with extra care and looking for kinks 44
12 35.1000 Y-90 Therasphere Events
- Prescribed 12,000 cGy - received 2,000 cGy (rad)
- Malfunction in the administrative set - significantly less pressure than usual to press syringe
- Saline accumulating in overflow vial
- Only returned portion of administration set that infused dosage into patient to manufacturer
- May have been a kink or obstruction in treatment catheter but not conclusive
- Will send complete administrative set next time 45 35.1000 Y-90 Therasphere Events One licensee - 2 reported medical events
- Report 1 - Prescribed 64.8 mCi, but received 41 mCi - 65% of activity
- Air bubbles noted in overflow tubing connected to the micro-catheter
- Connected 3-way stopcock between overflow tubing and micro-catheter aspirated bubbles to syringe with stopcock close to patient
- Resurvey of delivery kit showed residual activity 46*
35.1000 Y-90 Therasphere Events
- Report 2 - Prescribed 46 mCi but received 27 mCi -
59% of activity
- Used left radial artery with 5-French Sarah Radial catheter with coaxial micro-catheter
- Nothing unusual was encountered
- No radioactive contamination of the suite
- Dose was in catheter, gauze, dose vial and other waste 47 35.1000 Y-90 Therasphere Events
- Prescribed 89,200 cGy, but received 57,500 cGy -
64% of dose
- Backflow of microspheres into contrast line and syringe
- Significant contamination in contrast syringe, flushing syringe, contrast tubing, and associated y-adaptor
- Thought contrasting syringe and tubing were made of materials that bind microspheres more than administration kit - will look for same materials
- Will use clamp and one-way valve 48
13 35.1000 Y-90 Therasphere Events
- Prescribed 23 mCi, but received 7.4 mCi - 32% of the activity
- Blockage occurred in the delivery apparatus
- Imaged the administration set and saw most of the undelivered activity near where plunger connects to the dose vial
- Will send administration set and procedure waste to contractor for manufacturer 49 35.1000 Y-90 Therasphere Events
- Prescribed 35 mCi, but received 5.4 mCi - 16% of activity
- Microspheres were coagulated in the tubing
- Unexpected activity remained near the Touhy-Borst connector
- Manufacturer thought caused by issues with the micro-catheter
- Will flush micro-catheter immediately prior to connecting it to the administration kit 50 35.1000 Y-90 Therasphere Events
- Prescribed 13,000 cGy to left lobe of liver, but received 8,490 cGy - 65% of dose
- First vial administered without incident
- Second vial primed and prepped, but saw a train of bubbles in the line between the dose vial and patient
- AU stopped the procedure; did not want the bubbles to cause the flow to reflux into gastric artery and cause permanent damage to the stomach
- Could not pinpoint cause of bubbles
- Limit number of staff trained to prime and do set-up and ensure enough are available on treatment days 51 35.1000 Y-90 Therasphere Events
- Prescribed 24,500 cGy, but administered 13,083 cGy
- 53% of dose
- CT scan verified dose was administered to correct location
- Remainder of dose hung up in catheter despite flushing
- Catheter tubing met manufacturers specifications
- No root cause identified 52
14 35.1000 Y-90 Therasphere Events
- Prescribed 1,300 cGy to specific part of liver, but received 931 cGy - 71% of dose
- Used 3 different written directives to fractionate the delivery
- Thought the small activity prescribed contributed to under dose because of typical losses in the valve and tubing
- Order higher dosages for any administration below 10 mCi
- Amend license to go to different manufacturer 53 SirSphere 7
- Wrong site 2
- Measurement unit error 1
- Written Directive error 1
- High activity clogging 1
- Low activity administration 1
54 35.1000 Medical Events Wrong treatment site 2
- Prescribed 38.4 mCi to liver but received about 13 mCi to abdominal wall
- Post-treatment scan appeared normal with small uptake in bowel
- Pain in abdomen with erythema on abdomen -
thought dose was above 55 cGy but less than 1,000 cGy
- Thought one-third of dose migrated up a venous ligament and lodged in abdominal wall 55*
35.1000 Y-90 SirSphere Events Wrong treatment site (cont.)
- Difficult visualizing arterial access to the tumor
- Micro-catheter was not advanced far enough into correct artery
- Pre-existing kidney impairment precluded using more contrast
- Add second monitor to refer to original arteriogram without switching tasks and improve confidence of correct location
- Take prophylactic measures for future patients with impaired kidney function 56 35.1000 Y-90 SirSphere Events
15 Wrong site
- Prescribed 4,874 cGy to right lobe of liver, but received 11,080 cGy to left lobe
- Human error
- Placed catheter in left hepatic artery instead of right hepatic artery 57 35.1000 Y-90 SirSphere Events Measurement Unit Error
- Prescribed 0.91 GBq, but received 8.9 mCi
- Ordered 0.91 mCi - marked wrong box in computer
- Did not multiply measured dose value by correction factor of 10
- Not identify until post-procedure check
- Worksheet revised to be in SI units
- Written directive sheet to be in SI units
- Dose preparation and post-procedure forms to be in SI units 58 35.1000 Y-90 SirSphere Events Written Directive Error
- Prescribed 1,504 cGy to right lobe of liver, but received 1,498 cGy in left lobe
- Written directive prepared incorrectly - AU wanted to treat left lobe
- Identified after completion of the procedure
- AU did not indicate correct treatment site on written directive; AU did not forward pre-treatment information to the RSO
- Clinical staff failed to identify discrepancy during patient time-out just before the implantation 59 35.1000 Y-90 SirSphere Events High activity clogging 1
- Prescribed 4,320 cGy, but received 828 cGy - 19%
of the dose
- Micro-catheter clogging due to unusually large number of microspheres being used
- Prescribed activity was at high end of the treatment range
- Patient administration delayed 1 day - 25% increase in number of microspheres were needed to deliver the dose
- Will use smaller aliquots and/or slower infusion rate 60 35.1000 Y-90 SirSphere Events
16 Device malfunctioned 1
- Prescribed 32.5 mCi but received 8 mCi - 25% of activity
- Treatment device malfunctioned and ceased to deliver microspheres
- Manufacturers representative was present, but cause of malfunction is unknown
- Will return delivery device to manufacturer for technical analysis and root cause determination 61 35.1000 Y-90 SirSphere Events
- Prescribed 19.6 mCi to left lobe of liver, but received 10 mCi - 51% of activity
- Planned to deliver activity in two split dosages
- Written directive not properly reviewed, so split one dosage in two instead of the total dosage in two
- Radiation oncologist failed to check the drawn dosages prior to injecting them
- Identified after injection when the remainder of the dosage was discovered 62*
35.1000 Y-90 SirSphere Events
- Prescribed 19.6 mCi to left lobe of liver, but received 10 mCi - 51% of activity (cont.)
- Lack of comprehension of dose draw worksheet
- Miscommunication and failure to review the written directive
- Failure to perform a safety pause and properly review the dosage to be administered against the written directive prior to the administration 63 35.1000 Y-90 SirSphere Events Acronyms
- AU - Authorized User
- cGy - centiGray
- FY - Fiscal Year
- GBq - Giga Becquerel
- HDR - High Dose Rate Remote Afterloader
- I-124 - Iodine-124
- IVB - Intravascular Brachytherapy
- MBq - Mega Becquerel 64
17 Acronyms
- µCi - microcurie
- mCi - millicurie
- MIBG - Metaiodobenzylguanidine
- Pd-103 - Palladium-103
- RSO - radiation safety officer
- SI units - International System of Units
- Y Yttrium-90 65 QUESTIONS?
66