Peripheral joint radiographs
Record the actual regions, laterality and prescribed series. Hand and wrist studies may overlap; do not infer separate exposures simply from two report headings. Bilateral ×2 remains an approximation.
Professional workbench
Know what is in the number.
Inspect provenance, compare assumptions and retain a reproducible record. Effective dose is an approximate comparison quantity; individual risk assessment requires more information.
Calculation audit
| Examination | Arithmetic · mSv | Provenance |
|---|
Reference ceilings (†) are arithmetic placeholders, not upper bounds on a patient's dose. Imported and manually edited effective doses are user-supplied estimates. DLP, CTDIvol, KAP and absorbed dose are not accepted as effective dose.
Compare complete scenarios
Capture your current ledger as A. Change a dose, count or protocol in the ledger, then capture B. Snapshots remain separate from the ledger and are included in JSON exports.
SCENARIO A—
SCENARIO B—
Capture both scenarios to compare.
Inspect snapshot inputs
A lower dose does not establish diagnostic equivalence. These scenarios do not recommend a modality or follow-up interval.
Read the quantity before the number.
| Quantity | Typical unit | Interpretation |
|---|---|---|
| Effective dose · E | mSv / µSv | Reference-person, tissue-weighted quantity used for broad comparisons. This calculator accepts E, not an organ or fetal absorbed dose. |
| CTDIvol | mGy | CT output index based on a standard phantom. Record the phantom basis and protocol; it is not E. |
| DLP | mGy·cm | CT dose-length indicator. Review the scan extent and all acquisitions. There is no universal conversion into mSv. |
| KAP / DAP · PKA | mGy·cm² or Gy·cm² | Air kerma–area product for radiography/fluoroscopy. Confirm the displayed units. It is not a whole-body effective dose. |
| Reference air kerma · Ka,r | Gy | A fluoroscopic exposure indicator at a defined reference point. Not identical to peak skin dose; mSv totals cannot assess local skin injury. |
| Administered activity | MBq | Nuclear medicine activity, not dose. The radiopharmaceutical and any CT component must be identified. |
| Absorbed tissue / organ dose | mGy / Gy | Relevant to organ-specific questions and tissue reactions. Do not relabel it as effective dose. |
References: IAEA dose quantities · ICRP 147 · FDA fluoroscopy
Diagnostic reference levels are an optimization tool
Use the appropriate modality-specific quantity, clinical task, patient-size group and current jurisdictional reference. DRLs evaluate typical practice across groups of examinations; they are not individual patient dose limits. Review image quality as well as dose. An unusually low dose may require review if the examination no longer answers the clinical question. This calculator does not perform a DRL compliance assessment. ICRP 135 ↗
Rheumatology: details worth checking
Spine, pelvis and SI joints
Distinguish a pelvic examination from additional dedicated hip or SI projections. Do not multiply a pelvic dose by two. The SI reference in this tool comes from one study and is not a universal contemporary dose.
CT / HRCT of the lungs
Identify the actual acquisition protocol, including any expiratory or prone series. A lung-screening reference should not be substituted automatically for an ILD protocol. “High resolution” alone does not specify dose.
DXA and vertebral assessment
Distinguish conventional DXA, additional vertebral assessment, and CT-based bone density. Record the acquired regions and the supplied dose basis.
DECT for gout
Obtain a protocol-specific estimate: the scanned region and acquisition coverage matter. Do not substitute an abdomen CT or a generic extremity-radiograph value.
Fluoroscopy / nuclear medicine
Keep procedure-specific metrics and radiopharmaceutical details. For hybrid imaging, establish whether an estimate already includes the CT component before adding another CT dose.
These are data-reconciliation prompts, not modality-selection guidelines. References: the linked examination sources, ICRP 135 and the FDA/IAEA dose guidance.
Why there is no age/sex risk slider
Age at each exposure, sex, organs irradiated, dose distribution, population and competing mortality affect lifetime attributable risk. Applying a BEIR VII whole-body coefficient to a generic effective-dose sum creates an appearance of personalization that the input data do not support.
The optional illustration in Understand uses only the FDA fatal-cancer example: 10 mSv ≈ 0.05 percentage points of additional lifetime probability. It is not BEIR organ-dose modelling, cancer incidence or ICRP detriment. The display boundary at 100 mSv is a limitation of this simple illustration, not a threshold below which radiation has no risk.
No risk bands, medical dose quotas or comparison with acute radiation sickness thresholds are assigned to a cumulative history. Occupational and public dose limits are not patient imaging limits.