Evaluation of whole body dose reduction by modified injection technique.

Joemon JohnPET Imaging CentreGuy’s, King’s & St.Thomas’ School of MedicineKing’s College London

Evaluation of whole body dose reduction by modified injection technique.BACKGROUNDMATERIALS & METHODSRESULTSCONCLUSION

PET Imaging at St Thomas’ HospitalFacilities

two dedicated PET/CT scannerson-site cyclotronradiochemistry production laboratory

Scanning activityclinical & research scanning – 3,500 patient scans

per annumoncology, cardiology & neurology5 dedicated PET/CT scanning technologists /

radiographers

Radiation Protection Issues Increase in patient throughput with PET/CT

scanning raised concerns about staff whole body radiation dose

Imaging staff receive radiation when handling radioactivity & interaction with patients

65 % of staff WBD received when administering radiopharmaceutical activity to the patient

Staff Dose in mSv injecting

Total Dose in mSv

% from injecting

A 0.5 0.78 64%

B 0.33 0.58 56%

C 0.7 1.0 70%

D 0.93 1.35 68%

E 1.0 1.55 64%

Purpose of the studyTo improve the method of F-18 FDG

administration To evaluate a modified injection technique for

reducing staff WBDTo compare WBD received during the time of

administration by comparing the two different techniques

Materials & MethodsPersonnel involved

5 technologists

120 ambulatory clinical patients

Devicessyringe holders

lead shieldsdose monitor(Atomtex)extension tubing ( 30cm long, 1mm ID,

2mm OD )

Activity administrationOld technique New technique

Old technique

New technique

ResultsStaff member Doses in mSv

(old technique)

Doses in mSv(new technique)

Difference

A 1.07 0.63 40%

B 0.64 0.39 39%

C 1.5 0.94 38%

D 1.76 0.67 36%

E 0.65 0.5 28%

Results

A B C D E0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

OLDNEW

staff

mSv

ResultsMean WBD received during administration:

old technique was 0.64 – 1.9 mSv

new technique was 0.39 – 0.94 mSv

Other factor affecting WBD:speed of administration

ConclusionSimple techniqueCost effective - less than £1 per patient

increaseSignificant reduction in staff WBDIncreased patient throughput per day whilst

remaining within staff dose limits

Activity administrationOld technique New technique

Whole body dosesNo of clincal scans

done in 2006/07 - 3248

2007/08 - 3551

A B C D0

0.5

1

1.5

2

2.5

2006/072007/08

Other methods to reduce WBD

WBD Distribution5%

65%

7%

14%

10%

Drawing upAdministrationPatient changeScanner onScanner off