1 0 0 0 OA Single-chip pulse programmer for magnetic resonance imaging using a 32-bit microcontroller
- 著者
- Handa Shinya Domalain Thierry Kose Katsumi
- 出版者
- American Institute of Physics
- 雑誌
- Review of scientific instruments (ISSN:00346748)
- 巻号頁・発行日
- vol.78, no.8, pp.084705, 2007-08
- 被引用文献数
- 17 14
An MRI pulse programmer has been developed using a single-chip microcontroller (ADμC7026). The microcontroller includes all the components required for the MRI pulse programmer: a 32-bit RISC CPU core, 62 Kbytes of flash memory, 8 Kbytes of SRAM, two 32-bit timers, four 12-bit DA converters, and 40 bits of general purpose I/O. An evaluation board for the microcontroller was connected to a host PC, an MRI transceiver, and a gradient driver using interface circuitry. Target (embedded) and host PC programs were developed to enable MRI pulse sequence generation by the microcontroller. The pulse programmer achieved a (nominal) time resolution of approximately 100 ns and a minimum time delay between successive events of approximately 9 μs. Imaging experiments using the pulse programmer demonstrated the effectiveness of our approach.
1 0 0 0 OA Development of a local electromagnetic shielding for an extremity magnetic resonance imaging system
- 著者
- Handa Shinya Haishi Tomoyuki Kose Katsumi
- 出版者
- American Institute of Physics
- 雑誌
- Review of scientific instruments (ISSN:00346748)
- 巻号頁・発行日
- vol.79, no.11, pp.113706, 2008-11
- 被引用文献数
- 10 6
A local radio frequency (rf) shielding consisting of a Cu plate and an LC balun circuit has been developed for a compact magnetic resonance imaging (MRI) system with a 0.3 T permanent magnet. Performance of the local rf shielding was evaluated using an artificial external noise source irradiating a human subject whose hand was inserted into the rf coil of the MRI system. Power spectra of the rf signal detected through the rf coil demonstrated that the local rf shield achieved 30.1 dB external noise suppression. With the local rf shielding, a MRI of the subject's hand was performed using a three-dimensional gradient-echo sequence. Anatomical structures of the subject's hand were clearly visualized. It was concluded that the local rf shielding could be used for the compact MRI system instead of a rf shielded room.