TCM strength for GE scanners?
I hope you are doing well and thank for sharing the updated version of the NCICT software, As far as I know, the strength options of TCM given in the software are implemented in Siemens scanners, but other vendors use th
I hope you are doing well and thank for sharing the updated version of the NCICT software,
As far as I know, the strength options of TCM given in the software are implemented in Siemens scanners, but other vendors use the (off/on) option. I was wondering, If I am interested in using TCM for GE, for example, which strength should be equivalent for TCM ON in the GE scanners?
NCI Dose Team response
We created the feature based on a fundamental principle (modulating tube current based on the amount of attenuation across the patient anatomy within a fan beam) which is not specific to a certain make. The TCM strength concept came from the Siemens scanners but it is not corresponding to those of Siemens though. We are working on a way to calibrate this feature to work with different vendors including GE. If you have some idea how to do so, you’re welcome to send us your thoughts.
Community reply
As TCM strength is not vendor specific, does the strength means the deviation of modulated Tube Current from it's predefined value?
NCI Dose Team response
The generic TCM algorithm is based on the one published by Li et al. PMB 2014 (please see attached). The TCM profile is defined as:
modulated mA = reference mA x (attenuation at the angle theta / attenuation of reference phantom) ^ alpha
The TCM strength is alpha in this equation ranging from zero to unity.
Li-et-al.---2014---The-impact-on-CT-dose-of-the-variability-in-tube-c.pdf
Community reply
When GE head protocol with fixed Tube Current (140Kv-125 mA) is used for examination, is it correct to set TCM strength to 0.0, and the Current 125 and Limit 125?
NCI Dose Team response
That's correct but the mA limit does not matter as mA would not change anyway.