MR/PET combined scanner

November 21, 2010

PET/CT is a reality nowadays. PET provides functional information, while CT gives high resolution morphological information. The combination of both in one image perfectly aligned is highly important for a more accurate disease assessment. However, CT gives poor detail of soft-tissue and it involves a considerable amount of radiation, which means that MR/PET would be of high relevance. Having said that, it seemed to be nearly impossible to integrate MR and PET technologies: the conventional PET detectors, which use photomultiplier tubes, could not be used in the strong magnetic field generated by an MR system. Integration was further limited by the lack of space inside the MR device. Those difficulties seem to be part of the past, according to Siemens.
Biograph mMR Whole-Body Integrated MR-PET System is currently undergoing clinical use testing (not commercially available yet – no 510k yet).


Radiation-blocking underwear…

September 13, 2010

Airport X-ray scanners is the latest security measure that you have to go through before boarding a plane in the US. But, how safe are they? A lot to discuss about it… So far, you still got the option of getting a pat down. So no need to worry too much, right? Well, if you belong to those that think that soon there’ll be x-ray scanners everywhere, from schools to museums, etc., a company (Rocky Flats Gear) seems to have found the solution for you: ‘radiation-blocking’ underwear.
This all sounds very nice, but what happens with the rest of the body, doesn’t it get affected by radiation? Soon, we’ll have to be walking around on ‘radiation-blocking’ clothes. And the head? use an astronaut-like mask? How far can we go with those ”prevention” measures?

Having your patients hold their breath properly during a MR or CT scan is always a challenge, especially when your patients are infants. Mueller et al. have come up with a simple volume-monitored (VM) method for performing reproducible, motion-free full inspiratory and end expiratory chest CT examinations in children. They tested the method on
fifty-two children with cystic fibrosis (mean age 8.8 ± 2.2 years). They underwent pulmonary function tests and inspiratory and expiratory VM-CT scans (1.25-mm slices, 80–120 kVp, 16–40 mAs) according to an IRB-approved protocol. The VM-CT technique utilizes instruction from a respiratory therapist, a portable spirometer and real-time documentation of lung volume on a computer. CT image quality was evaluated for achievement of targeted lung-volume levels and for respiratory motion. Overall, 94% of scans were performed at optimal volumes without respiratory motion. This method is applicable to children older than 4 years-old.
A drawback of the method, though, is the fact that the respiratory therapist has to stay in the room while the scan is being performed, with all the risks of radiation.

For more information you can read the whole article, published online in Pediatric Radiology (May 28, 2010): Volume-monitored chest CT: a simplified method for obtaining motion-free images near full inspiratory and end expiratory lung volumes