🕹 O-ARM MACHINE
🔘 The O-arm surgical imaging system is a mobile X-ray system designed for 2D fluoroscopic use and 3D imaging and is intended to be used where physician benefits from 2D and 3D information of anatomic structures and objects with high X-ray attenuation such as bony anatomy and metallic objects.
🔘 It provides intra operative imaging of patient anatomy in real time and it provides high quality images with large field of view.
🔘 It was launched in 2006 by Medtronic.
🔘 It is a multi dimensional surgical imaging platform optimized for use in
⚫ Spine surgeries
⚫ Trauma related surgeries
How it works
💢 It consists of X-ray source and flat panel detector, these are incorporated in gantry called as ring.
💢The ring can be opened and closed, so that patient doesnt have to be moved. It rotates to take 2D real time moving X-rays and 3D images of the body.
💢 It includes a navigational component, like a GPS system, that allows the surgeon to track and guide instruments through the body in real time, ensuring the placement of hardware or implant more precisely.
💢 The navigation system converts the 3D image on the O-arm into a transparent image, like an x-ray. The images of the anatomy, includes bones and implants.
💢 It helps in cases where large areas need to be visualized. The processing is fast, capturing the entire cervical spine in one 13 second scan. In less than 30 seconds, the O-arm can take almost 400 images, which are reconstructed on a flat-panel monitor for reviewing.
💢 These images provide information, that the hardware or implant has been positioned in optimal location, avoiding a second surgery.
🎯 Fast 3D reconstruction displays axial, coronal, saggital views in seconds
🎯 It enables lateral patient access
🎯 Enclosed gantry system maintains sterile field and safety
🎯 Can take 391 images in 13 seconds
🎯 Low dose mode provides images at 50% lower dose to patient compared to standard mode
🖲 It uses distortion free flat panel detectors 30cm x 40cm with 3 Mega pixel (1.5k x 2k) resolution.
🖲 It has powerful 32Kw generator to enable imaging of heavier patients.
🖲 In 3D mode the system offers two levels of image acquisition using a 512 x 512 x 192 reconstruction matrix.
🖲 Standard Definition 3D,
– Exposure time= 13 sec and 391 images over 360 degrees
🖲 High Definition 3D,
– Exposure time= 26 sec and 750 images over 360 degrees
🖲 2D fluoroscopic pictures- The detection acquires images 3 times bigger than 9 standard C arm, simplifying treatment of large fractures
GANTRY MOTION RANGES
🔮 Up/ down – 18 inches (45cm) total range
🔮 Left/ right = +/- 7 inches(17.8cm) in either direction
🔮 In/ out – 18 degrees away from cabinet
🔮 Tilt – 45 degrees around center axis
🔮 Isowag motion – 12 degrees
🔮 Wag – 15 degrees
⚠ During 3D spin acquisition, person who remain in room should be at either end of gantry, 2 metres away and protected by barrier of not less than 0.5 mm of lead.
⚠ When imaging with O arm, always follow ALARA guidelines (As Low As Reasonably Achievable)
⚠ Reduce exposure time if possible, with lowest dose that gives adequate image quality
⚠ Effective dose for conventional operation ranges from 1.5 mSv to 6.9 mSv
PROS AND CONS
🔵 Highly precise and used in image guided surgery
🔵 High spatial resolution and self propulsion
🔵 Eliminates manual repositioning
🔵 Low dose rate
🔵 Isowag isocentric positioning eliminates need to reposition gantry for off axis imaging
⭕ The O arm uses significantly two to three times more radiation than C arm using O arm in conjunction with navigation system helps to control exposure of dose
⭕ Breakable gantry
⭕ Highly expensive
By : S.M. Inthiyas 3rd year BME Student B V Raju Institute of Technology,
Hyderabad, Telangana, India.
Work Together Develop Together