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Status of Medical Events FY 2014

Donna-Beth Howe, Ph.D.

Medical Radiation Safety Team

March 19, 2015

Medical Events 2014

• 43 Medical events reported - FY 2013

• 46 Medical events reported - FY 2014

FY13 FY14

35.200 0 1

35.300 2 3

35.400 15 5

35.600 10 10 

35.1000 16 27

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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.

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Medical Events 2014

35.200 Medical events 1

Technetium-99m

• Administered entire multi dose vial 140 mCi to

single patient

– 6-7 cGY (rad) whole body

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2

Medical Events 2014

35.300 Medical events 3

Samarium 153 1

• Administered 39 microcuries to skin of arm

• Intended 100 microcuries intravenously

Radium – 223 1

• Error in writing millicuries in written directive 

• administered micro curies

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I-131 1

• 30 millicuries delivered to wrong patient

• Patient was given bracelet id of another patient 

• Authorized User did not use another identifier to 

confirm the patient was correctly identified

• 728 cGy(rad) to the thyroid

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35.300 Medical Events

Medical Events 2014

35.400 Medical events 5

Gynecological 1

Prostate 4

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35.400 Medical Events 

Gynecological Cs-137 1

• Dislodged applicator 

• Treatment time 49.5 hours – planned 63.1 

• Treatment site received 78% of intended dose

• inner thighs received up to 1,509 cGy (rad) 

expected 652 cGy (rad).

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35.400 Medical Events

Prostate 4

• Air Kerma - received 18,400 cGy (rad) 

instead of the prescribed 14,500 cGy (rad) 

medical physicist mistakenly ordered using 

mCi instead of the air kerma value.

• Some seeds inadvertently implanted into the 

scar tissue - 54% of prescribed dose 

delivered to treatment site

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35.400 Medical Events

Wrong Site - Ultrasound Issues 2

• Seeds implanted 3.5 cm inferior from the 

target location 29.31% of the prescribed 

dose was delivered to the target tissue. 

• 88 seeds were implanted in penile bulb 

34 seeds prostate gland attending 

urologist mistook the penile bulb for the 

prostate gland

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Medical Events 2014

35.600 Medical events 10

HDR 9 

• Skin 2

• Bronchial 1 

• Not designated 2

• Pelvic 1

• OBGYN 3

Gamma knife 1

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Medical Events 2013

35.600 Medical events 

HDR 9

• Wrong Site 3

• Wrong Patient 1

• Decay correction 1 

• Right patient wrong treatment plan 1

• Source Retraction 1

• Wrong dwell time 1

• Wrong interpretation of dose per fraction 1

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4

35.600 Medical Events

HDR Wrong Site 3

• OBGYN - wrong location during three treatment 

fractions of 700 cGy (rad) per fraction

• During follow-up visit burns observed to the skin on the 

patient’s thighs and labia. 

• The estimated skin dose received by the patient was 

4,200 cGy (rad). 

• the source was 100 mm short of the intended treatment 

site due to Source reference length error,. 

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35.600 Medical Events

HDR Wrong Site cont.

• Broncial/tracheal - each fraction had two 

segments, a distal portion using a simple 

catheter and a proximal portion using a 

centering catheter. 

• In 1st fraction the centering catheter was 

positioned incorrectly 

• Treatment offset of 9 cm superior to the 

intended treatment site

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35.600 Medical Events

HDR Wrong Site cont.

• OBGYN - first of three fractions vaginal cylinder 

position checked with planar digital x-ray image and 

unusual inferior cylinder placement was noted, 

attributed to special patient anatomy. 

• On next fraction vaginal cylinder was approximately 5 

cm superior to the first treatment..

• dose in 1st fraction to unintended tissue was 900 cGy

(rad) and 100 cGy (rad) was to the intended tissue.

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35.600 Medical Events

HDR Wrong Patient – Skin 1

• physicist selected a different patient's treatment plan 

with shorter channel length 

• The correct site and applicator were used

• Recognized error when time was too long – manually 

stopped procedure

• Intended treatment site received less than half of the 

500 cGy (rad) intended dose, 

• Area adjacent to the intended site received a maximum 

dose of 2,300 cGy (rad) to a single point and 1,000 cGy

(rad) to a 1 cm radius and 4.5 mm depth

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35.600 Medical Events

HDR Decay correction – Skin 1

• Decay corrected value for the source activity 

was used in data entry for the treatment plan. 

• HDR software also corrected for decay in 

determining the exposure time for the fraction

• patient received approximately twice the 

prescribed 600 cGy (rad) during a skin 

treatment

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35.600 Medical Events

HDR Wrong Treatment Plan – 1

• Two Ir-192 high dose rate (HDR) fractions of 

700 cGy (rad) each

• The patient returned for the second fraction and 

treatment plan for the first fraction instead of 

the second fraction was loaded. 

• 700 cGy (rad) to 60% of intended dose 

received by planned volume. 

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35.600 Medical Events

HDR Source retraction – Pelvic 1

• Received 5.94 cGy (rad) of the prescribed 300 

cGy (rad), 

• First fractions, unexpected resistance detected 

in moved to the second dwell position. 

• HDR unit detected a delay and automatically 

retracted the source. 

• The dummy source wire could not traverse the 

pathway and the treatment was abandoned. 

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35.600 Medical Events

HDR Dwell time – unspecified 1

• Before third of six fractions an error was 

identified in planning the correct dwell position 

for the first two fractions. 

• Corrective actions included updating 

procedures to provide all catheter 

measurements, producing a checklist of 

necessary equipment for the operating room, 

briefing staff physicists in utilizing the 

equipment, and hiring additional staff.

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35.600 Medical Events

HDR Wrong interpretation of dose per 

fraction – OBGYN 1

• Intended treatment was three fractions of 500 

cGy (rad) each

• During the second of three fractions error noted 

• Treatment plan was set to deliver three 

fractions for a total of 500 cGy (rad) 

• Cause was attributed to human error. 

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35.600 Medical Events

Gamma knife 1

• Two similar patients arrived and had head 

frames attached 

• Scheduling change to treat only patient 2 was 

made with out communicating the change to 

nursing staff 

• Patient identification was not checked

• Physician realized mistake 2 minutes into the 

treatment

• 175 cGy (rad) to the wrong site. 

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Medical Events 2014

35.1000 Medical events 28

Perfexion 1

I-125 Seed localization 1

Y-90 Microspheres 24

SirSphere ® 15

Therasphere ® 9

Gliasite 1

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35.1000 Medical Events

Perfexion 1

• Treatment prescribed for left side of brain. 

• Treatment planner set up plan for right side of brain as 

done for two previous treatments 

• Incorrect treatment plan was reviewed and signed 

• The treatment stopped at 1.72 minutes into the 19.14 

minute procedure. 

• Approximately 1,800 cGy (rad) deliver to wrong site. 

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35.1000 Medical Events

I-125 Seed localization 1

• received two I-125 seeds when only one was intended. 

• The patient had two marker clips, one for benign biopsy 

site and other for a papilloma. 

• the benign site was marked with a 9.32 MBq (252 μCi) I125 seed

• The unintended dose from two days seed placement 

was 61 cGy (rad) at 0.5 cm

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Y-90 Microspheres 24

SirSphere ® 15

– Wrong site 2

– Written Directive 1

– 3-Way Stopcock 2

– Bubbles 1

– Contamination 1

– Transfer error 1

– Occluded /kinked catheters 6 

– No Information 1 

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35.1000 Medical Events

35.1000 Medical Events

SirSphere ® Wrong Site 2

• Duodenal Ulcer

– First of 3 treatments – 36.2 mCi (1,339 MBq)

– Duodenum lesion and an ulcer that had developed 

seemingly as a result of microspheres migrating to 

the stomach. 

– A biopsy of the affected region revealed synthetic 

beads. 

– Aberrant hepatic arterial vasculature supplying the 

stomach.

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35.1000 Medical Events

SirSphere ® Wrong Site cont. 

• Gastric fundus 

– 1,100 cGy (rad) to the gastric fundus

– Prescribed microspheres to the right liver 

lobe 

– Stopped when unanticipated shunting was 

identified. 

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35.1000 Medical Events

SirSphere ® Written Directive 1

• Over dose 36,300 rad instead of 10,200 rad

– Authorized user provided radiopharmacist

with an incorrect version of the written 

directive treatment form

– failure to follow all procedures and the defeat 

of normal checks and balances that should 

have identified the incorrect dosage

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35.1000 Medical Events

SirSphere ® 3 Way Stopcock 2

• 45.8 % under Dose

– Majority of undelivered Y-90 in and around 

the 3-way stop

– 3-way stop system was defective 

• 29.7% under dose

– Microspheres in the tubing near the stop 

cock valve

– Dextrose not Saline

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35.1000 Medical Events

SirSphere ®

• 75 % under Dose

– Noticed bubbles in the administration line 

during the treatment and stopped. 

• 44.7 % under dose

– elevated readings at the catheter/vial 

interface - coagulation of microspheres. 

– contamination on physician’s glove and table

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35.1000 Medical Events

SirSphere ®

• 34 % under Dose

– Error transferring microspheres from the 

delivery vial to the dosing via. 

• 22.7 % under dose

– Larger than expected amount of 

microspheres remained in the needle and 

tubing and did not reach the patient. 

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35.1000 Medical Events

SirSphere ®

• 22.5 and 30 % under Dose

– Split dose, not detected until end of both.

– Blockage in the delivery system.

• 25 % under dose

– catheter clogged halfway through the 

procedure

– catheter removed, replaced, and remaining 

microspheres administered

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35.1000 Medical Events

SirSphere ®

• 41% under Dose

– Same lobe but two different arterial 

pathways.

– No microspheres delivered to second part.

– Short arterial segment and the acute angle at 

the arterial origin, with possible manipulation 

or patient movement, resulted in a kink or 

fold

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35.1000 Medical Events

SirSphere ®

• 41.1% under Dose

– blockage 

– Not problem with administration kit .

– Significant number of kinks, bends, clots, and 

other blockages at catheter tip

• 32.2 under Dose

– last bolus could not be pushed through

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35.1000 Medical Events

SirSphere ®

• 38% under Dose

– No information provided

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Y-90 Microspheres cont.

Therasphere ® 9

– Wrong site 2 

– Reflux & Precipitated out 1

– Dosage error 1

– Remained in vial 1

– Settle out /kink 4

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35.1000 Medical Events 35.1000 Medical Events

Therasphere® Wrong Site 2 

• SHUNTING - Two tumors right and left lobes

– Tested right hepatic artery found shunting -

intended 370 cGy (rad) to lung

– Treated left lobe through left hepatic artery –

untested shunting

– lungs received 3,450 cGy (rad)

– Patient died 5 months later

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35.1000 Medical Events

Therasphere®

Wrong site - Catheter Position Error 

• Could not properly position the catheter for 

Segment IV 

• Bilateral disease that would eventually require 

the treatment of both lobes 

• 0.81 GBq (21.8 mCi) to Segment IV and 0.91 

GBq (24.5 mCi) in the right lobe. 

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35.1000 Medical Events

Therasphere®

Reflux & Precipitated out 

• 24 % under dose – noted some reflux into the 

common hepatic artery/gastroduodenal artery.

• reduced flow rate during administration 

process, which resulted in the precipitation of 

microspheres along the outflow tube 

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35.1000 Medical Events

Therasphere®

Dosage error over dose 

• Written directive for 20 % less activity.

• Reviewed treatment plan but verified standard 

activity not prescribed activity

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35.1000 Medical Events

Therasphere®

• 20% remained in vial

• 44% under dose

– Targeting vessel was flowing slowly

– Microspheres to settle out prior to reaching 

the target.

• 73 % under dose

– Wrong catheter - kinking

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35.1000 Medical Events

Therasphere®

• 23.5% under dose

– Microspheres adhered to the connector and 

first one inch of manufacturer supplied tubing 

• 28.7% under dose

– kink in the delivery catheter - created 

blockage 

– thinner, more flexible catheter walls and a 

small internal catheter diameter were 

contributing factors. 

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35.1000 Medical Events

GliaSite

• No dose to treatment site

– The balloon had not inflated incorrectly 

positioning a three-position stopcock

– I-125 saline solution being diverted to 

another syringe instead of filling the balloon.

– The stopcock was not part of the vendor’s kit

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Acronyms

• FY – Fiscal Year

• HDR – High Dose Rate Remote Afterloader

• mCi – millicurie

• MBq – Mega Becquerel

• Pts - Patients

• Y – Yttrium

• I-131 – Iodine-131

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QUESTIONS?

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