A project of mine.

HDR motion study

• Background– Hollow plastic catheters implanted through the skin into the prostate

– Implant locked together and stitched to the patient’s skin

– A tiny radioactive source moved through the catheters in the prostate and treats it from the inside

– Very tightly defined dose distribution

– Called brachytherapy and is a very successful treatment

– Patients lie in hospital and get 2 treatments over 2 days

Next slide not for the squeamish!

HDR Motion study • Collection of catheters into prostate• The template is being stitched to the skin

HDR Motion study

• Problem– The catheters tend to move out of the patient

• Question– Is this due to movement of the patient while in bed in hospital, or is it

due to swelling?

The Project

• To get a measure of patient movement while in bed

• Uses electronic inclinometers to measure angles of legs and torso

• Based on solid state accelerometer

• Now cheaply available since used in laptops to detect motion

• If acceleration detected HDD suspends operation

Inclinometer

• Device measures ‘static acceleration’ due to gravity

• Can easily calculate angle to vertical

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yaTan

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Analysis

• Angle of leg to vertical can be calculated

• Use with sensor on abdomen to find hip flexion

Leg Angle (rel horizontal)

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•Search for correlation between hip flexion/extension angles and implant movement.

Results

• No relationship between patient movement and implant displacement.

• In publication

Spares

• Following slides just junk for recycling

• An opportunity to review restrictions on patient movement

• May reinforce/reduce need to for patients to lie still

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Prevalence Vs Incidence

• Autopsy results

• Patients did not die from the cancer.

Waveguide cont