John Craig PhD and Monique Craig BSCE, APF: Calibration for radiography of the equine hoof

Forge Knowledge, September 2019

The FRC is content to accredit 2 (two) CPD points for the completion and submission of correct answers to this article. Forge magazine will advise the FRC of those successfully achieving their points for audit purposes only subject to completion of the agreement below

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* 1. I authorise the Forge to share the results of this survey with the Farriers Registration Council for the purpose of auditing my CPD activity.

Signed -

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* 2. Why is a horse's hoof generally stood on a block to create a proper radiograph?

X-rays might reflect off the ground surface and cause distortion.

Due to the divergence of the x-ray beam, the lower portions of the hoof capsule will not be imaged unless they are raised relative to the lower edge of the film or detector panel.

For health and safety of the operators.

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* 3. Is it possible to position the x-ray generator, subject anatomy, and detector panel so that there is no magnification in the image?

Yes, by carefully adjusting OFD and FFD.

No. There is always magnification in a radiographic image.

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* 4. What is an advantage of the ‘two-ball scale marker’ compared to the ‘one-ball scale marker’.

The two points used for calibration are farther apart - giving a better baseline which is less prone to errors due to pixelization.

Easier to place on the anatomy of interest.

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* 5. Is the measurement of the palmar angle robust to small misalignment of the imaging system?

Yes. With some amount of care, the value can be measured within a degree.

No. If the equipment is not aligned properly, the result will be useless.

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* 6. What are some length measurements of the hoof that would be important to know accurately?

Sole thickness, HL-zones (describe the distance from front hoof wall to the pedal bone).

The angle of the coronary band.

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* 7. Can sophisticated software automatically detect a scale marker built into a block?

Yes

No, not yet.

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* 8. With a typical X-ray generator, how best to describe the shape of the volume of space irradiated?

A cone.

A truncated pyramid.

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* 9. Why, for the best measurements, should you move the X-ray generator farther from the subject?

Exposes the patient to less radiation.

Minimises the ‘distortion’ in the image due to varying magnification values through a thick subject.

Question Title

* 1. I authorise the Forge to share the results of this survey with the Farriers Registration Council for the purpose of auditing my CPD activity.Signed -

Question Title

* 2. Why is a horse's hoof generally stood on a block to create a proper radiograph?

Question Title

* 3. Is it possible to position the x-ray generator, subject anatomy, and detector panel so that there is no magnification in the image?

Question Title

* 4. What is an advantage of the ‘two-ball scale marker’ compared to the ‘one-ball scale marker’.

Question Title

* 5. Is the measurement of the palmar angle robust to small misalignment of the imaging system?

Question Title

* 6. What are some length measurements of the hoof that would be important to know accurately?

Question Title

* 7. Can sophisticated software automatically detect a scale marker built into a block?

Question Title

* 8. With a typical X-ray generator, how best to describe the shape of the volume of space irradiated?

Question Title

* 9. Why, for the best measurements, should you move the X-ray generator farther from the subject?

* 1. I authorise the Forge to share the results of this survey with the Farriers Registration Council for the purpose of auditing my CPD activity.

Signed -