DigitizerProjectionActor does not work on parallel world

[buimhh]

I have a problem implementing a parallel world in SPECT.
From my understanding, it may come from the DigitizerProjectionActor.
I reused one exercise of David to demonstrate the error.

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import opengate as gate
import opengate.contrib.spect.genm670 as spect_ge_nm670
from pathlib import Path

if __name__ == "__main__":
    # create the simulation
    sim = gate.Simulation()

    # main options
    sim.g4_verbose = False
    sim.visu = False
    sim.visu_type = "vrml"
    # sim.visu_type = "qt"
    sim.number_of_threads = 6
    sim.random_seed = "auto"

    # units
    m = gate.g4_units.m
    sec = gate.g4_units.second
    days = 3600 * 24 * sec
    cm = gate.g4_units.cm
    mm = gate.g4_units.mm
    nm = gate.g4_units.nm
    MeV = gate.g4_units.MeV
    keV = gate.g4_units.keV
    Bq = gate.g4_units.Bq
    kBq = 1000 * Bq
    MBq = 1000 * kBq

    # world size
    sim.world.size = [2 * m, 2 * m, 2 * m]
    sim.world.material = "G4_AIR"

    # waterbox
    wb = sim.add_volume("Box", "waterbox")
    wb.size = [30 * cm, 30 * cm, 30 * cm]
    wb.material = "G4_AIR"
    wb.color = [0, 0, 1, 1]  # blue

    spect, crystal = spect_ge_nm670.add_ge_nm67_spect_head(
        sim, "spect", collimator_type="megp", debug=sim.visu
    )

    sim.add_parallel_world("parallel_world")
    spect.mother = "parallel_world"
    spect.translation = [0, 0, -28 * cm]




    # spect digitizer
    channels = [
        {"name": f"spectrum", "min": 3 * keV, "max": 515 * keV},
        {"name": f"scatter", "min": 380 * keV, "max": 420 * keV},
        {"name": f"peak", "min": 400 * keV, "max": 450 * keV},
    ]
    # spect digitizer
    proj = spect_ge_nm670.add_digitizer(sim, "spect_crystal", channels) # issue come from this line
    # proj is the Projection image
    proj.output = Path("output") / "projection2_star.mhd"

    # Lu177 source (only the gammas)
    source = sim.add_source("GenericSource", "fake")
    source.particle = "gamma"
    source.mother = f"waterbox"

    source.energy.type = "spectrum_lines"
    source.energy.spectrum_weight = [0.114, 0.259]
    source.energy.spectrum_energy = [218.12 * keV, 440.45 * keV]
    source.position.type = "sphere"
    source.position.radius = 1 * mm
    source.position.translation = [0, 0, 0 * mm]
    source.direction.type = "iso"
    if sim.visu:
        sim.number_of_threads = 1
        source.activity = 2 * Bq
    else:
        source.activity = 4 * MBq / sim.number_of_threads
    source.half_life = 6.647 * days

    # add stat actor
    s = sim.add_actor("SimulationStatisticsActor", "stats")
    s.track_types_flag = True
    s.output = Path("output") / "stats2_star.txt"

    # phys
    sim.physics_manager.physics_list_name = "G4EmStandardPhysics_option3"
    sim.physics_manager.set_production_cut("world", "all", 1 * mm)

    # ---------------------------------------------------------------------
    # start simulation
    # sim.running_verbose_level = gate.EVENT
    time_per_slice = 1 * sec
    no_of_run = 5
    sim.run_timing_intervals = gate.runtiming.range_timing(0, time_per_slice * no_of_run, no_of_run)
    motion = sim.add_actor("MotionVolumeActor", f"Move_{spect.name}")
    motion.mother = spect.name
    motion.translations, motion.rotations, = gate.geometry.utility.volume_orbiting_transform(
        "z", 0, 180, no_of_run, spect.translation, spect.rotation)


    sim.run()

    # print stats
    stats = sim.output.get_actor("stats")
    print(stats)

[jizhang02]

Hello,
I want to project the simulation at the direction of xz, I don't know if they have implemented this function.

[buimhh]

Hello,
If I am not wrong, you meant detectors are rotated around the z-axis.
If yes, you can find one example of siemens intevo here:
https://github.com/OpenGATE/opengate/blob/master/opengate/contrib/spect/siemens_intevo.py#L641
Hope it helps.
Regards,

[jizhang02]

Hello, If I am not wrong, you meant detectors are rotated around the z-axis. If yes, you can find one example of siemens intevo here: https://github.com/OpenGATE/opengate/blob/master/opengate/contrib/spect/siemens_intevo.py#L641 Hope it helps. Regards,

Hi,
Thank you for this info, that indeed helps. Actually, when I'm doing SPECT simulation, the last step is projection. The projection image is generated at the axial direction, while I want to change the view with coronal, I tried to change detector direction, but it seems not working.