[Intl_DxMedPhys] Siemens tube current modulation question

Wed Apr 23 14:32:19 EDT 2025

Hello Ryan,
  There is no modulation in the Z-direction under Cardiac CT, CACs or CCTA, with Siemens scanners. Siemens does adjust the dose according to the patient chest size and the Qref mAs, but there is no mA change on the patient along the table movement direction.
  The dose is also adjusted according to the cardiac ECG gating. MinDose is part of the ECG gating.

Jimmy Zhou
Cedars-Sinai Medical Center

From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces+yifang.zhou=cshs.org at lists.osu.edu> On Behalf Of Ryan Fisher via Intl_dxmedphys_wd_osu_list
Sent: Wednesday, April 23, 2025 10:32 AM
To: intl_dxmedphys_wd_osu_list at lists.osu.edu
Subject: [External] [Intl_DxMedPhys] Siemens tube current modulation question

Hello! I’m digging into a question about our cardiac calcium scoring protocols. In poking through the DICOM info for scans across various Siemens scanners we noticed a variety of modulation types listed under the (0018 9323) “Exposure Modulation

Hello! I’m digging into a question about our cardiac calcium scoring protocols. In poking through the DICOM info for scans across various Siemens scanners we noticed a variety of modulation types listed under the (0018 9323) “Exposure Modulation
Hello!

I’m digging into a question about our cardiac calcium scoring protocols. In poking through the DICOM info for scans across various Siemens scanners we noticed a variety of modulation types listed under the (0018 9323) “Exposure Modulation Type” tag. Does anyone happen to have any info on the values listed below? It’s been a while since I’ve dug into TCM details. For the OFF_ZEC scans, the mA values change with anatomy though the patient, but all the others look to be scaling mA to patient size but keeping it fixed throughout a given patient scan.

FWIW these came from a variety of Siemens scanners/vintages, including a Somatom Perspective, Force, Definition Edge, and Somatom.go All.

FIX_EC
PULS_MINDOSE_EC
PULS_EC
OFF_ZEC

Any info would be much appreciated.

Thanks!
Ryan

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Ryan Fisher, PhD, DABR, MRSE (MRSC™)
Department of Radiology
Chief Diagnostic Medical Physicist
Radiation Safety Officer
O 216.778.5453|  M 216.978.5276  |  rfisher1 at metrohealth.org<mailto:rfisher1 at metrohealth.org>
MetroHealth Main Campus  |  2500 MetroHealth Drive, Cleveland, OH 44109
Associate Professor
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