Not Your Parents' Gamma Camera
Not Your Parents' Gamma Camera
By William L. Hubble, M.A., CNMT, RT, (R)(N)(CT), FSNMTS
Posted on: November 10, 2009
Link to original article
One of the many advantages of attending nuclear medicine conferences is the opportunity to preview new imaging equipment. Within the past few years, vendors have introduced several innovative imaging cameras that will change the way we perform nuclear medicine scans. Allow me to introduce you to some of these new machines.
All of the systems I'm discussing are cameras that employ semiconductor detectors and/or other unique imaging hardware. Semiconductors typically offer better energy and spatial resolution than what is expected from conventional NaI gamma cameras. This equates into high quality patient images with shorter acquisition times. Other systems redesign the conventional gamma camera or modify the collimators to offer overall improvements. Most of these systems provide additional diagnostic information and improve patient comfort.
One such system is the Discovery NM 530c with Alcyone technology by GE. This gamma camera can increase standard cardiac acquisition times by 400 percent. The Alcyone technology consists of cadium zinc telluride (CZT) solid state detectors, focused collimation and 3-D reconstruction-with no detector motion. GE combines this system with a 64-slice Lightspeed VCT CT scanner in the Discovery NM/CT 570c to enable a complete cardiac scan consisting of SPECT, attenuation correction, calcium scoring and CT angiography in less than five minutes.
Another innovative gamma camera is the D-SPECT cardiac imaging system by Spectrum Dynamics. The D-SPECT also employs CZT detectors. Its uniqueness comes in the form of nine independently operating detectors. The use of these detectors increases the sensitivity of the D-SPECT by a factor of 10 compared to a conventional gamma camera. A gated SPECT of the heart can be performed in two minutes! Patients are in a natural sitting position (they don't have to raise their arms overhead), and there's no perceivable camera and chair motion. If you dig innovative camera technology, take a look at this camera.
The CardiArc, another relatively new dedicated cardiac imaging system, employs three curved NaI detectors with a unique collimation system. The system advertises an increase in acquisition times by a factor of five or more. Acquisition is performed in the upright seated position, with detector boards arranged in a 180-degree arc around the patient. Between the detectors and the patient is a thin sheet of lead called the aperture arc. The aperture arc has 6 narrow slots that collimate the incoming photons within each slot. The positions of the aperture arc slots define a "line of sight" into the patient for each detector pixel; the aperture rotates back and forth during acquisition. This is the only moving camera part and is not seen by the patient or technologist. This approach provides angle sampling at one sample every 0.14 degrees as compared to one every 3 degrees in a conventional camera. Diagnostic images can be obtained in as little as 60 seconds with no adjustment of dose.
Two other systems uniquely designed for breast imaging are the Dilon 6800 gamma camera and the NaviScan PET scanners. The Dilon 6800, distributed by Philips Healthcare, features more than 3,000 individual crystals and 48 position-sensitive photomultiplier tubes (PMTs). The camera is portable and has a moveable detector head that allows imaging in all mammographic positions, plus selective study of hard-to-reach areas such as the axilla. The system has a predicted resolution of 3 mm. The NaviScan scanner is a dedicated PET mammography unit that features a short 4 to 10 minute scan time and 2 mm spatial resolution. Compact and portable, it uses 50 percent less compression than a radiographic mammogram. Take a look at these PEM images!
Finally, Digirad offers several solid state gamma cameras. The Digirad 2020tc, plugged into a standard wall outlet, is portable and uses Cesium Iodide[Tl] detectors with pixelated crystals. The 2020tc can be fitted with different collimators to perform many routine nuclear medicine procedures. It's approved for radionuclides with an energy of 60-300 KeV. Digirad also offers the C1 XPO single-head SPECT system, C2 XPO dual head cardiac SPECT system and C3 XPO triple head SPECT system. The chair turns as patients are imaged in an upright sitting position.
There are many substantial developments occurring in molecular imaging instrumentation, and these companies are leading the way.
William L. Hubble, MA, CNMT, RT, (R)(N)(CT), FSNMTS is associate professor, NMT program director and chairman of the department of medical imaging and radiation therapeutics at the Doisy College of Health Sciences at Saint Louis University, in St. Louis
By William L. Hubble, M.A., CNMT, RT, (R)(N)(CT), FSNMTS
Posted on: November 10, 2009
Link to original article
One of the many advantages of attending nuclear medicine conferences is the opportunity to preview new imaging equipment. Within the past few years, vendors have introduced several innovative imaging cameras that will change the way we perform nuclear medicine scans. Allow me to introduce you to some of these new machines.
All of the systems I'm discussing are cameras that employ semiconductor detectors and/or other unique imaging hardware. Semiconductors typically offer better energy and spatial resolution than what is expected from conventional NaI gamma cameras. This equates into high quality patient images with shorter acquisition times. Other systems redesign the conventional gamma camera or modify the collimators to offer overall improvements. Most of these systems provide additional diagnostic information and improve patient comfort.
One such system is the Discovery NM 530c with Alcyone technology by GE. This gamma camera can increase standard cardiac acquisition times by 400 percent. The Alcyone technology consists of cadium zinc telluride (CZT) solid state detectors, focused collimation and 3-D reconstruction-with no detector motion. GE combines this system with a 64-slice Lightspeed VCT CT scanner in the Discovery NM/CT 570c to enable a complete cardiac scan consisting of SPECT, attenuation correction, calcium scoring and CT angiography in less than five minutes.
Another innovative gamma camera is the D-SPECT cardiac imaging system by Spectrum Dynamics. The D-SPECT also employs CZT detectors. Its uniqueness comes in the form of nine independently operating detectors. The use of these detectors increases the sensitivity of the D-SPECT by a factor of 10 compared to a conventional gamma camera. A gated SPECT of the heart can be performed in two minutes! Patients are in a natural sitting position (they don't have to raise their arms overhead), and there's no perceivable camera and chair motion. If you dig innovative camera technology, take a look at this camera.
The CardiArc, another relatively new dedicated cardiac imaging system, employs three curved NaI detectors with a unique collimation system. The system advertises an increase in acquisition times by a factor of five or more. Acquisition is performed in the upright seated position, with detector boards arranged in a 180-degree arc around the patient. Between the detectors and the patient is a thin sheet of lead called the aperture arc. The aperture arc has 6 narrow slots that collimate the incoming photons within each slot. The positions of the aperture arc slots define a "line of sight" into the patient for each detector pixel; the aperture rotates back and forth during acquisition. This is the only moving camera part and is not seen by the patient or technologist. This approach provides angle sampling at one sample every 0.14 degrees as compared to one every 3 degrees in a conventional camera. Diagnostic images can be obtained in as little as 60 seconds with no adjustment of dose.
Two other systems uniquely designed for breast imaging are the Dilon 6800 gamma camera and the NaviScan PET scanners. The Dilon 6800, distributed by Philips Healthcare, features more than 3,000 individual crystals and 48 position-sensitive photomultiplier tubes (PMTs). The camera is portable and has a moveable detector head that allows imaging in all mammographic positions, plus selective study of hard-to-reach areas such as the axilla. The system has a predicted resolution of 3 mm. The NaviScan scanner is a dedicated PET mammography unit that features a short 4 to 10 minute scan time and 2 mm spatial resolution. Compact and portable, it uses 50 percent less compression than a radiographic mammogram. Take a look at these PEM images!
Finally, Digirad offers several solid state gamma cameras. The Digirad 2020tc, plugged into a standard wall outlet, is portable and uses Cesium Iodide[Tl] detectors with pixelated crystals. The 2020tc can be fitted with different collimators to perform many routine nuclear medicine procedures. It's approved for radionuclides with an energy of 60-300 KeV. Digirad also offers the C1 XPO single-head SPECT system, C2 XPO dual head cardiac SPECT system and C3 XPO triple head SPECT system. The chair turns as patients are imaged in an upright sitting position.
There are many substantial developments occurring in molecular imaging instrumentation, and these companies are leading the way.
William L. Hubble, MA, CNMT, RT, (R)(N)(CT), FSNMTS is associate professor, NMT program director and chairman of the department of medical imaging and radiation therapeutics at the Doisy College of Health Sciences at Saint Louis University, in St. Louis
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