A system for low field imaging of laser-polarized noble gas.
We describe a device for performing MRI with laser-polarized noble gas at low magnetic fields (<50 G). The system is robust, portable, inexpensive, and provides gas-phase imaging resolution comparable to that of high field clinical instruments. At 20.6 G, we have imaged laser-polarized (3)He (Larmor frequency of 67 kHz) in both sealed glass cells and excised rat lungs, using approximately 0.1 G/cm gradients to achieve approximately 1 mm(2) resolution. In addition, we measured (3)He T(2)(*) times greater than 100 ms in excised rat lungs, which is roughly 20 times longer than typical values observed at high ( approximately 2 T) fields. We include a discussion of the practical considerations for working at low magnetic fields and conclude with evidence of radiation damping in this system.
Wong
G P
GP
Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA.
Tseng
C H
CH
Pomeroy
V R
VR
Mair
R W
RW
Hinton
D P
DP
Hoffmann
D
D
Stoner
R E
RE
Hersman
F W
FW
Cory
D G
DG
Walsworth
R L
RL
D000818:Animals; D004867:Equipment Design; D006371:Helium; D007554:Isotopes; D007834:Lasers; D008168:Lung / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008297:Male; D008433:Mathematics; D019047:Phantoms, Imaging; D011846:Radio Waves; D051381:Rats; D017207:Rats, Sprague-Dawley
D007554:Isotopes; D006371:Helium