The Improvements and Options of Bone Densitometers


Bone densitometers are very powerful machine but are generally underutilized and employed in imaging modality. According to research in osteoporotic fractures in woman the numbers of woman with the condition are greater than the population suffering from breast cancer, stroke and heart attack combined. There are three main methods used in bone densitometers and while you may be looking to replace or consider your options here are the different approaches.

Pencil Beam

Pencil beams uses a singular beam of x-ray to generate an image is the original technology as a bone densitometers. The single bean travels across the measured region or entire body. While the pencil beam machine is the original machine and has always been seen as the standard for bone thing it is a long process for the beam to gradually move across the area and collect the data from its single beam. The pencil beam is seen as the choice where there is low demand for the procedure. The GE Lunar DPX Duo and GE Lunar DPX Bravo are great examples of pencil beam DXA systems

Fan Beam

Fan beam, also referred to as wide angle fan beam, was introduced as a substitute for the pencil beam. The x-ray instead of a single beam is constructed with a number of tube emissions with multiple detectors moving across an area. While there is minimal distortion compared to the accurate pencil beam, the fan beam has taken been seen as the future with a much shorter scan time.  

Narrow Angle Fan Beam

The last method is known as the third generation of DXA machines, Narrow Angle Fan Beam or Micro Angle Fan Beam. This technology developed and introduced by General Electric Healthcare division is still technically a fan beam. The difference is that a number of narrow beams pass over a measured area producing a number of images. It proposes to be the best of both worlds taking the gold standard of pecison from the pencil beam and the speed from the fan beam. Image construction software takes these images and constructs an image based on the series of images compiled during the procedure. The GE Lunar Prodigy Primo and Advance are third generation systems that are recommended for practices scanning more than 15 patients per day. The developments in the area of bone densitometers has allowed the dose of radiation to decrease while improving the image quality and general results for both  bone mineral content (BMC) and bone mineral density (BMD).

The narrow fan beam (4.5) orientated parallel to the longitudinal axis of the body. Compared to previous densitometers where the fan beam was positioned perpendicular to the longitudinal axis of the body. The fan beam angles of 30 and 12. A dual-energy X-ray source with peak X-ray energy of 80kVp and a current of 3mA with a K-edge filter (cerium 300mg/cm2) gives effective energies of approximately 38 and 70keV. The images are usually constructed over a 24mm length with longitudinal steps of 17mm. Pixel size are arranged according to the procedures for spine, femoral neck, and total body standard scan modes are 0.6 1.05, 0.6 1.05 and 4.8 13.0 mm compared to 1.2 1.2, 1.2 1.2 and 4.8 9.6mm for the DPXL. In the case of fan beams the while the technology and results are the finest there remains a magnification effect to reduce this effect; a software correction is utilized with the Prodigy densitometer. The times for the scanning procedures to measure areas are impressive with standard mode spine and femoral neck being reduced to 30 seconds and total body to 5 minutes compared to 8 seconds and 20 minutes for medium scan mode.