Page MenuHomec4science
Files F66487446

opts.py
No OneTemporary
Actions

File Metadata

Created
Mon, Jun 10, 20:56

opts.py
View Options

from pypulseq.convert import convert
class Opts:
"""
System limits of an MR scanner.
Attributes
----------
adc_dead_time : float, default=0
Dead time for ADC readout pulses.
gamma : float, default=42.576e6
Gyromagnetic ratio. Default gamma is specified for Hydrogen.
grad_raster_time : float, default=10e-6
Raster time for gradient waveforms.
grad_unit : str, default='Hz/m'
Unit of maximum gradient amplitude. Must be one of 'Hz/m', 'mT/m' or 'rad/ms/mm'.
max_grad : float, default=0
Maximum gradient amplitude.
max_slew : float, default=0
Maximum slew rate.
rf_dead_time : float, default=0
Dead time for radio-frequency pulses.
rf_raster_time : float, default=1e-6
Raster time for radio-frequency pulses.
rf_ringdown_time : float, default=0
Ringdown time for radio-frequency pulses.
rise_time : float, default=0
Rise time for gradients.
slew_unit : str, default='Hz/m/s'
Unit of maximum slew rate. Must be one of 'Hz/m/s', 'mT/m/ms', 'T/m/s' or 'rad/ms/mm/ms'.
Raises
------
ValueError
If invalid `grad_unit` is passed. Must be one of 'Hz/m', 'mT/m' or 'rad/ms/mm'.
If invalid `slew_unit` is passed. Must be one of 'Hz/m/s', 'mT/m/ms', 'T/m/s' or 'rad/ms/mm/ms'.
"""
def __init__(self, adc_dead_time: float = 0, gamma: float = 42.576e6, grad_raster_time: float = 10e-6,
grad_unit: str = 'Hz/m', max_grad: float = 0, max_slew: float = 0, rf_dead_time: float = 0,
rf_raster_time: float = 1e-6, rf_ringdown_time: float = 0, rise_time: float = 0,
slew_unit: str = 'Hz/m/s'):
valid_grad_units = ['Hz/m', 'mT/m', 'rad/ms/mm']
valid_slew_units = ['Hz/m/s', 'mT/m/ms', 'T/m/s', 'rad/ms/mm/ms']
if grad_unit not in valid_grad_units:
raise ValueError(f"Invalid gradient unit. Must be one of 'Hz/m', 'mT/m' or 'rad/ms/mm'. "
f"Passed: {grad_unit}")
if slew_unit not in valid_slew_units:
raise ValueError(f"Invalid slew rate unit. Must be one of 'Hz/m/s', 'mT/m/ms', 'T/m/s' or 'rad/ms/mm/ms'. "
f"Passed: {slew_unit}")
if max_grad == 0:
max_grad = convert(from_value=40, from_unit='mT/m', gamma=gamma)
else:
max_grad = convert(from_value=max_grad, from_unit=grad_unit, to_unit='Hz/m', gamma=gamma)
if max_slew == 0:
max_slew = convert(from_value=170, from_unit='T/m/s', gamma=gamma)
else:
max_slew = convert(from_value=max_slew, from_unit=slew_unit, to_unit='Hz/m', gamma=gamma)
if rise_time != 0:
max_slew = 0
self.max_grad = max_grad
self.max_slew = max_slew
self.rise_time = rise_time
self.rf_dead_time = rf_dead_time
self.rf_ringdown_time = rf_ringdown_time
self.adc_dead_time = adc_dead_time
self.rf_raster_time = rf_raster_time
self.grad_raster_time = grad_raster_time
self.gamma = gamma
def __str__(self):
s = "System limits:"
s += "\nmax_grad: " + str(self.max_grad) + str(self.grad_unit)
s += "\nmax_slew: " + str(self.max_slew) + str(self.slew_unit)
s += "\nrise_time: " + str(self.rise_time)
s += "\nrf_dead_time: " + str(self.rf_dead_time)
s += "\nrf_ring_time: " + str(self.rf_ringdown_time)
s += "\nadc_dead_time: " + str(self.adc_dead_time)
s += "\nrf_raster_time: " + str(self.rf_raster_time)
s += "\ngrad_raster_time: " + str(self.grad_raster_time)
s += "\ngamma: " + str(self.gamma)
return s

Event Timeline

c4science · Help