Table 2:

Modified 4D CT protocol in our current patient^{^a}

Phase	Measurement
Phase	CTDI_vol (mGy)	DLP (mGy.cm)
Arterial	26.92	475
DE-venous^{^b}	31.78	583
Delayed	26.68	471
Total	85.38	1529
% Reduction from standard protocol	21.6	18.4

Note:—CTDI_vol indicates CT dose index volume; DLP, dose-length product; DE, dual-energy.
↵a These measurements obtained during our modified 4D CT scan on the current patient were compared with values obtained during standard 4D CT (including the precontrast scan) of another weight- and sex-matched patient. Both CTDI_vol and DLP measurements were recorded during modified 4D CT (excluding the precontrast scan) for the current patient (61.6-kg female patient) illustrated in this case presentation. They showed an estimated 20% reduction in the radiation exposure.
↵b The venous phase scan was acquired using dual-energy CT (DE-venous) to obtain the VNC image.