Table 3.

Comparison of key protocol settings contributing to dose differences between maximum and minimum DLP_75kg systems

Examination	Clinical purpose of CT	Max/min DLP75kg	Max or min DLP75kg protocol	Scan length (cm)	Summary of main protocol differences contributing to variation in DLP75kg
PET/CT brain	Localisation/characterisation	16.8	Max	18	Exceptionally high effective mAs for localisation/characterisation (images originally intended for diagnostic use)
			Min	23
PET/CT and SPECT/CT cardiac	AC only	19.6	Max	29	High effective mAs for AC only; long scan length
			Min	16	Attempted to optimise for AC only with low effective mAs (low mA, high pitch) and low kV; use of IR
SPECT/CT lung	AC only	27.4	Max	32	High kV; high effective mAs for AC only
			Min	36	Attempted to optimise for AC only with low effective mAs (low mA, high pitch); use of IR
	Localisation/characterisation	4.2	Max	32	Higher kV and effective mAs than minimum DLP75kg protocol
			Min	33	Low kV and effective mAs
SPECT/CT bone	Localisation/characterisation	10.0	Max	106	Three times greater scan length, higher kV and effective mAs than minimum DLP75kg protocol
			Min	37	Use of IR
SPECT/CT parathyroid	Localisation/characterisation	7.8	Max	28	Much higher effective mAs (but lower kV) than minimum DLP75kg protocol
			Min	24