. Author manuscript; available in PMC: 2013 Aug 14.

Published in final edited form as: AJR Am J Roentgenol. 2013 Jul;201(1):142–146. doi: 10.2214/AJR.12.9181

TABLE 1.

Protocol Specifications and Typical Technical Chest Radiographic Parameters Used in the National Lung Screening Trial

Parameter	Film-Screen	Computed Radiography	Digital Radiography

Tube voltage (kV)	120–150	100–140	110–150
Maximum skin entrance exposure (mGy)^a	0.3	0.4	0.3
Maximum exposure time (ms)	40	40	40
Source-image distance (in)^a	≥ 72	≥ 72	≥ 72
Antiscatter device (grid)	≥ 10:1 at 103 lines/in (stationary) or 80 lines/in (reciprocating)	Optimal for system	Optimal for system
Minimum collimation	To image receptor	To image receptor	To image receptor

Note—72 in = 182.88 cm, 1 in = 2.54 cm.

Skin entrance exposure may exceed these guidelines in large individuals.