TESTING OF PULSE SEQUENCES

All research pulse sequences that are to be used on human subjects must be approved by the CAMRIS committee prior to human use. Formal approval from the CAMRIS committee or its designee is required before use of a research sequence on any volunteer, including the researchers themselves. Research pulse sequences include those written at HUP or any other institution or corporation. The only sequences that are exempted are those provided by the manufacturer as product and are used within the parameters and protocols for which they were developed. Overriding the design of a product sequence using "control variables" requires CAMRIS approval. Modification of any aspect of an approved sequence requires CAMRIS re-approval before human use is allowed. Additionally, disabling of the RF power monitor is prohibited.

We anticipate that the approval process will only require the documentation of steps that are already being performed by researchers in the development of their sequences, so this process should not represent a burden. Our goal is to formalize and document these procedures. The approval procedure requires the following documents to be submitted to the CAMRIS committee:

1.A brief description of the sequence, paying particular attention to the RF pulse parameters and duty cycle. Include in this description the method of the SAR estimation. SAR may be calculated using the RF pulse structure and code within the pulse sequence, or may be calculated separately. Comparing the new sequence to an existing approved sequence can be a helpful approach. If the sequence is to be used on the 4 Tesla magnet only, then SAR calculations are not necessary since a maximum power estimate has already been performed for the coil approval.

2. A copy of the actual pulse sequence source code on diskette.

3. A timing diagram of the pulse sequence. This diagram should be generated by the sequence development tools on the workstations. This will document the expected sequence output. Please provide the value of the control value ‘xmtaddScan’ and make sure that the appropriate gradient configuration file (usually 1.5T_SR120_config.cvs) is used when performing the sequence simulation. If multiple ‘boffsets’ are used within the sequence, provide a timing diagram for each sub-sequence. Please use sufficient resolution so as to discern areas of interest (for example, gradient rise times) and turn on axis labeling. Multiple pages may be required to show sufficient detail.

4. A phantom image using the new sequence.

When naming the sequences, use a numeric extension that increments on each revision (for example, fgre0, fgre1, … fgreN) so that modifications and their subsequent approval can be documented. Each revision will require CAMRIS approval. Many revisions may qualify for expedited approval as described below.

Documents will be submitted for approval at the CAMRIS meeting following their submission. Sequence changes that do not significantly alter the dB/dt or RF may be reviewed by Larry Dougherty or Hee Kwon Song in an expedited fashion and then presented at the next CAMRIS meeting.