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Molecular Computer Tomography realized October 23, 2008

Posted by tomography in CT, Innovation, PET, Tomography.
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Biograph_mCT_Internet.jpg

Siemens Healthcare introduced Biograph mCT at the European Association of Nuclear Medicine conference in Munich, Germany. The latest addition to their scanner line-up offers:

  • 5 minute whole body PET/CT scans with 2mm slice thickness
  • shorter scanning time
  • wider (78cm) ring diameter
  • low patient dose rate
  • up-to 128 slice CT scans

Further reading:

– Andras

PET/CT Reader On Your iPhone June 28, 2008

Posted by tomography in Innovation, Nuclear Medicine, PET, Radiology, SPECT.
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When the iPhone came out I said: “I gotta have one of this!” As I am entering the last year of medical school and edging more towards real clinical imaging work in the field of nuclear medicine I say : “I need one of these as soon as possible!”

MIM for iPhone

I wrote about how iPhones could be used in diagnostic imaging and why all radiologist should carry one in their pockets wherever they go, but now PET/CT readers have a reason to do so as well. MimVista has just recently come out with a multi-modality imaging software for the iPhone that is absolutely mind blowing.

You may not only view PET/CT combined data on your phone, but you may use all those tools that you are used to on a workstation. For example:

  • find the contour of the lesion in 3D
  • calculate min. and max. SUV values
  • calculate the volume of the lesion.

And that is just of the many uses of this software that soon may change the way we learn and work!

Take a look at this video to find out more about this emerging technology:

Further reading:

– Andras

The whole brain Atlas March 17, 2008

Posted by tomography in CT, education, MRI, Nuclear Medicine, PET, Radiology, Tomography.
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This morning we’ve received a very helpful comment from Y.S., who is running a medical blog also, prep4md.blogspot.com. He suggested, to visit the site of Harvard Medical School. The library I could explore there was amazing to me.

In The Whole Brain Atlas you can view MRI sections through a living human brain as well as corresponding sections stained for cell bodies or for nerve fibers. The stained sections are from a different brain than the one which was scanned for the MRI images…

foramen monro

A great collection to explore neuroimaging for students and even for MDs. In the Normal brain section you can set slice, anatomical structure, choose between MRI T1 or T2 and even PET. There are some Quicktime motion pictures eg of vascular anatomy. Diseases are sorted, so you can study these separative groups: Cerebrovascular, Neuroplastic, Degenerative and Inflammatory or Infectious disease.

MRIs are allowed anyone to use them with no restrictions as long as you mention their source. Therefor the Copyright information:

All of the images on this site are copyrighted. They were produced with the support of public funds, and we wish to keep them available for public use. You may use them for any purpose which will not interfere with their use by others. We do ask that you SECURE OUR PERMISSION, so that we can track the uses being made.

There is no charge for the permission nor for the use of the images. The permission process is important for our guidance in producing additional images and also for maintaining our public support. We also ask that you credit this site as the source of the image(s), and the National Science Foundation for its support.

Thank you for the tip Y.S!

-Imre

What tomorrow brings? October 22, 2007

Posted by tomography in Nuclear Medicine, PET, Radiology, SPECT, Tomography, What tomorrow brings?.
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rtgwifehandThe radiologist who sits in a dark room, interpreting films and rendering a report that someone looks at hours later is becoming a thing of the past. Well, does it?
Of course, in this way, it couldn’t work nowadays, in the 2nd millenium – though we should not forget some poor parts of the world, where
some 20-30-40 year old machines are still in use . Basicly Konrad Roentgen’s X-ray was very important in past and shall be in the future, as it started a revolution many years ago, – which we still witness – diagnostic imaging.

 

 

xrayvirt

Since then, his invention went through a great evolution. Just take a look at the latest X-ray machines. They look nice, they work fine…, but they simply do not cover all the basis. As time went by, came new ideas, so we have CT and MRI in our hands (for many years fortunately). CT and MRI are sensitive in defining that disease is present, but they aren’t specific in determining what particular type of disease may be present. PET was the answer as it really brought it’s dramatic change. The increased metabolic activity not only confirms that cancer is present but it also provides evidence of staging or metastasis beyond the primary. Utilization of PET began in the 1990s. (SPECT has been around for decades, and it is preferred over PET in cardiac cases.) PET and SPECT are both basic gadgets in nuclear medicine, which combines chemistry, physics, mathematics, computer technology, and medicine in using radioactivity to diagnose and treat disease. Nuclear medicine procedures are safe, they involve little or no patient discomfort and do not require the use of anesthesia. Finally, CT-MRI and PET-SPECT found each other in a good working marriage, so one of today’s high-end stuff is PET-CT.

Can we go further? What is the next step?

Many say, that the most exciting development is the coming of molecular medicine. By understanding the molecular basis of disease and developing methods to detect and treat changes in the body at the molecular level, physicians will be able to identify diseases in the earliest possible stages. Cancer is one area experts already are seeing progress.

 

Molecular imaging is poised to become the future of nuclear medicine. The role of the nuclear imaging specialist in molecular therapy is to provide detailed information regarding the nature of biologic processes using radiopharmaceuticals in concert with positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging.

How about nanomedicine?

Nanomedicine may be defined as the monitoring, repair, construction and control of human biological systems at the molecular level, using engineered nanodevices and nanostructures. Once nanomachines are available, the ultimate dream of every healer, medicine man, and physician throughout recorded history will, at last, become a reality. Programmable and controllable microscale robots comprised of nanoscale parts fabricated to nanometer precision will allow medical doctors to execute curative and reconstructive procedures in the human body at the cellular and molecular levels. But the ability to direct events in a controlled fashion at the cellular level is the key that will unlock the indefinite extension of human health and the expansion of human abilities.

Nanomedicine FAQsnanomed

to be continued

“Time-of-Flight” takes off in PET/CT October 5, 2007

Posted by tomography in CT, Nuclear Medicine, PET, Tomography, Uncategorized.
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TOF or time-of-flight reconstruction is actually not a recent invention in tomography as its application in diagnostics was first proposed in the 1980s, but only recent technological improvements allowed its use in scanners. In a diagnostic scan improvement means better image quality, and less tracer dose for the patient.
In a PET scan when a positron collides with an electron, two gamma rays are generated in the annihilation process. The detector ring is looking for two, almost “simultaneous” rays, which is then noted as an event and is stored as data. Naturally, only those two rays are simultaneous, that traveled the same distance. Therefore using the time difference (fraction of a second) between the gamma rays, the scanner can pinpoint the original location of the positron-electron annihilation.tofschematic

http://www.chm.bris.ac.uk/ms/theory/tof-massspec.html

To best understand it, you need to look at conventional PET imaging, which involves the injection of a decaying radioactive agent into a patient. As each nucleus decays, a positron is released that immediately collides with an electron, creating an annihilation that releases a pair of photons, or gamma rays. These two photons travel away from the collision point at 180° from each other. After detecting the photons, the PET scanner’s computer uses that information to calculate where the radioactive agent is concentrated and produce an image localizing the affected area. TOF makes it possible for point of origination of annihilation to be more accurately predicted, which leads to more accurate imaging. Improved event localization reduces noise in image data, resulting in higher image quality, shorter imaging times, and lower dose to the patient

A time-of-flight mass spectrometer uses the differences in transit time through a drift region to separate ions of different masses. It operates in a pulsed mode so ions must be produced or extracted in pulses. An electric field accelerates all ions into a field-free drift region with a kinetic energy of qV, where q is the ion charge and V is the applied voltage. Since the ion kinetic energy is 0.5mv2, lighter ions have a higher velocity than heavier ions and reach the detector at the end of the drift region sooner.

TOF is especially useful in examining overweight patients who have been traditionally difficult to image.

Alzheimer World Day September 27, 2007

Posted by tomography in Alzheimer's Disease, Nuclear Medicine, PET, Tomography.
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2007. september 20th, Thursday, was the offical world day for Alzheimer’s Disease (A.D). According to researchers, by the year 2050 there will be more than 100 000 000 people living with this illness all around the globe. The same study points out that the most significant increase can be expected in Asia. This region already gives 50% of patients suffering from Alzheimer’s (Medical-Tribune.hu). Here is a collection of websites , where you can find out more about this severe and irreversible disease:

You will find a very detailed summary here including risk factors, histology, and treatment options:

The Alzheimer’s Association’s website is aimed at patients and family, where they can find all the necessary information including the latest scientific discoveries, support groups, and upcoming events.

Take this fascinating Brain tour and go deep inside the human brain to find out the very origins of A.D.:

Here You will find an interesting slide show presentation titled “Descent Into Alzheimer’s,” that speaks about this illness through the language of Art.

Here are some high resolution images related to this disease:

Portrait of an Alzheimer’s patient:

petscan.jpg

A recent discovery can help in the early diagnosis of patients, which in turn can lead to more successful treatment. Click on the image below to read more. (http://www.neuro.fsu.edu/faculty/fadool/petscan.jpg).

am_ta.gifImages in the upper row are representative PET examples performed in an Alzheimer’s diasease patient. Those in the bottom row are from the control subject. These transaxial images were taken at the level of the hippocampus, and they show:

  1. decreased glucose metabolic rate in the temporal lobe (middle collumn)
  2. significantly decreased serotonin 1A receptor density as a result of cell loss (right collumn)
  3. increased presence of plaques and neurofibrillary tangles (left collumn)

Moving towards the future: PET/CT June 24, 2007

Posted by tomography in CT, Nuclear Medicine, PET, Radiology, Tomography.
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There is radiology, where usually one gets an ultrasound scan, or a normal X-ray, or even a CT scan done, and nuclear medicine where doctors are looking for pre-cancerous lesions or metastasis with the help of radioactive molecules.

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And then there is the combination of the two, PET/CT, which not only helps doctors locate the lesion more accurately (CT), but it also helps determine how active that lesion is on the molecular lever (PET) using one machine, and one sitting (actually lying) for the patient.

“Positron Emission Tomography requires the patient to ingest or inject a radioactive isotope, for example, fluorodesoxyglucose (FDG) which releases positrons at the cellular level. These collide with electrons creating a light pattern (from photons) that can be scanned. The key aspect of this technology is that pre-cancerous cells typically show heightened metabolic activity that can be detected early on.”

This technology has been used to locate tumors, identify metastasis, but its real power lies in the fact that in the near future it may in the diagnostic process replace PTCA or – percutanorous transluminal coronary angioplasty- which is an invasive method with several severe risks. Therefore atherosclerosis and blood clogs will be detected early on with as little pain and side-effect to the patient as one injection can cause.

Take a look at a promotional video (Hungarian) to find out more about this fascinating new technology, or watch this video (English):

You will find some technical information about the data acquisition process in PET scanner in this post: