Will frusemide administered to horses prior to scintigraphic examinations reduce the radiation dose rate?

Erichsen C*, Falck-Andersen H*, Lønning M*, Bjørnstad A*, Eksell P #

*Norwegian School of Veterinary Science, Oslo – Norway # Private practice, Ôrbyhus - Sweden

Introduction

Scintigraphy has high sensitivity for lesions in bone

Scintigraphy is commonly used in equine practice

Introduction

Radiation safety

The radiation dose from the horse has been claimed to be reduced after administration of frusemide.

No published data to support this.

Introduction

Pilot study at SLU, Uppsala 31 horses in two groups

3 measurepoints Measured at 2, 6 and 24

hours post injection No difference between groups

Present study with improved method at NVH, Oslo

More horses 1 measurepoint 2 and 24 hours post

injection

Purpose

To determine if administration of frusemide prior to scintigraphic examinations reduce the radiation dose rate from the horse at 2 and 24 h post injection.

Material

74 HorsesReferred to NVH for scintigraphic examination

32 horses

Group F (Frusemide)Group C (Control)

42 horses

Material

Group F Horses referred for scintigraphic examinations including the

pelvis

Group C All horses referred for scintigraphic examinations of areas

other than the pelvis

Material

Group F Group C

Age 7,4 8,1

BW (kg) 517 522

Dose 99mTc-HDP(MBq/kg BW)

10,3 10,1

Dose frusemide(mg/kg BW)

0,33 -

Material

Group F Group C

Age 7,4 8,1

BW (kg) 517 522

Dose 99mTc-HDP(MBq/kg BW)

10,3 10,1

Dose frusemide(mg/kg BW)

0,33 -

Method

All horses injected with radiopharmaceutical 99mTc HDP (10 MBq/kg BW)

Placed in a dedicated stableControlled area

Method

Group F Frusemide i.v. one hour post injection

Group C Control horses

Method

Geiger Müeller survey meter Canberra Military

Pocket Radiac

Accumulated Radiation

dose during minimum 30

min was registered

beginning

2 hours post injection 24 hours post injection

Method

Highest radiation dose 15 cm cranial to the tuber coxae against the skin

Method

Highest radiation dose 15 cm cranial to the tuber coxae against the skin

Method

Material and Methods

All measurements werecorrected for time relatedto the time of injectionand converted into Sv/hour.

Minimum level of significance was set to p0.05

Results

No significant differences in measured radiation dose between the groups

Hours after injection

Sv/h

0

10

20

30

40

50

60

70

80

2 24

F C

Results

Radiation dose (Sv/hour)

Mean Range

2 hours 63,6 39-100

24 hours 3,4 2-7

Results

Radiation dose (Sv/hour)

Mean Range

2 hours 63,6 39-100

24 hours 3,4 2-7

Myocard scan 100 60-160

Bone scan 31 30-38

Results

Significant correlations:

1. Dose 99mTc-HDP and radiation dose Higher dose gives higher

radiation dose

2. Bodyweight and radiation dose Increased BW gives lower

radiation dose

Discussion

Claimed Advantages

Encourage urination

Improve image quality

Less radiation dose to personell

Claimed Disadvantages

Possible increased restlessness during

examination

Increases the risk of contamination by radioactive

urine

Discussion

Claimed Advantages

Encourage urination

Improve image quality

Less radiation dose to personell

Claimed Disadvantages

Possible increased restlessness during

examination

Increases the risk of contamination by radioactive

urine

Conclusion

Dose 99mTc & Horse size matters

Conclusion

For radiation safety reasons it should not be

recommended to administer frusemide to all

horses that undergo scintigraphy.

Administration of frusemide should only be

recommended when pelvic imaging is performed,

because of the increased risk of radioactive

contamination due to urination.

Acknowledgements

The three students that did

most of the measurements

during 2006

Technicians at the Equine

section, NVH

Anders Unoson

Thank you for your attention!