CT Effective Dose Calculator

Convert DLP to effective dose (mSv) for any anatomical region and patient age group

Parameters

DLP — Dose-Length Product (mGy·cm)

Anatomical region

Patient age group

—

mSv

Effective dose from DLP:

\( E\;[\text{mSv}] = \text{DLP}\;[\text{mGy·cm}] \times e_{\text{DLP}} \times k_{\text{age}} \)

e_DLP — dose conversion coefficient (region-specific). k_age — pediatric age multiplier (1.0 for adults).

Region	e_DLP (mSv / mGy·cm)	Phantom
Head	0.0021	16 cm
Head and Neck	0.0031	16 cm
Neck	0.0059	16 cm
Chest / Thorax	0.014	32 cm
Abdomen	0.015	32 cm
Pelvis	0.015	32 cm
Neck + Chest	0.014	32 cm
Chest + Abdomen	0.015	32 cm
Abdomen + Pelvis	0.015	32 cm
Chest + Abdomen + Pelvis	0.015	32 cm
Neck + Chest + Abdomen + Pelvis	0.015	32 cm
Whole Body / Trunk	0.015	32 cm
Pelvis + Thighs	0.012	32 cm
Pelvis + Thighs + Shins	0.010	32 cm
Pelvis + Thighs + Shins + Feet	0.009	32 cm
Abdomen + Pelvis + Thighs	0.014	32 cm
Abdomen + Pelvis + Thighs + Shins	0.012	32 cm
Abdomen + Pelvis + Thighs + Shins + Feet	0.010	32 cm

Age group	Head / Neck	Chest	Abdomen / Pelvis
Adult (> 17 years)	1.0	1.0	1.0
13–17 years	1.1	1.1	1.1
8–13 years	1.3	1.4	1.5
3–8 years	1.7	1.6	1.6
6 months – 3 years	2.2	1.9	2.0
Newborn – 6 months	2.6	2.2	2.4

Calculator is for planning and audit purposes only and does not replace device-reported dose values.

Status: Direct citation from international standards.

ICRP Publication 60 (1991) — biological tissue weighting factors that underlie e_DLP.
AAPM Report No. 96 (2008) — aapm.org/pubs/reports/RPT_96.pdf
European Guidelines on Quality Criteria for CT (EUR 16262 EN) — source of phantom-specific (16 cm head / 32 cm body) coefficients.
MU 2.6.1.2944-11 — National radiation hygiene methodical guideline, Table 6.1.

Status: Direct citation.

Status: Conventional clinical interpolation, not a direct citation.

e_DLP = 0.015 mSv/(mGy·cm) is used for any combination including the abdomen, equal to the trunk-region value from the standards.
Neck+Chest uses 0.014 (chest dominates the scan length).
Rationale: in routine practice, scanners report a single combined DLP for multi-region acquisitions, and the trunk coefficient is the conventional choice. Reference: AAPM Report 204 (2011), Size-Specific Dose Estimates.

Status: Length-weighted estimate. Verify against your local DRLs.

Pure leg e_DLP ≈ 0.0008 mSv/(mGy·cm) — low organ-weighting factors below the pelvis.
Source: AAPM Report 96, extremity coefficient.
Published whole-runoff (abdomen → feet) coefficient ≈ 0.013–0.015.
Source: Christner JA, Kofler JM, McCollough CH. Estimating Effective Dose for CT Using DLP and the European Guidelines. AJR 2010;194:881–889 — doi:10.2214/AJR.09.3462
Per-subdivision values (Pelvis+Thighs, +Shins, +Feet, etc.) are length-weighted interpolations between the pelvis (0.015) and pure-leg (0.0008) extremes.

Status: Reference orientation only — not a Diagnostic Reference Level (DRL).

UNSCEAR 2008/2020 — global typical effective doses by procedure.
Mettler FA et al. Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog. Radiology 2008;248:254–263 — doi:10.1148/radiol.2481071451
For clinical compliance, compare against your institutional or national DRLs (e.g., national DRL register, ICRP Publication 135).

Green — value comes directly from a published standard. Yellow — value is a clinical estimate or interpolation; verify before clinical use.