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IR(ME)R incident: notification codes, categories and criteria

Use these codes when you report an IR(ME)R incident.

Notification code Exposure category Criteria for notification a, b

Accidental exposure

England only
All modalities including therapy 3 mSv effective dose or above (adult)
1 mSv effective dose or above (child) c
(Northern Ireland, Scotland and Wales)
All modalities including therapy All, regardless of dose

Unintended exposure

All modalities including nuclear medicine and radiotherapy pre-treatment imaging
2.1 Intended dose less than 0.3mSv 3mSv or above (adult)
1mSv or above (child)
2.2 Intended dose between 0.3mSv and 2.5mSv 10 or more times than intended
2.3 Intended dose between 2.5mSv and 10mSv 25mSv or above
2.4 Intended dose more than 10mSv 2.5 or more times than intended
3 Interventional/cardiology Where there has been NO procedural failure AND either:
the dose is 10 or more times the Local Diagnostic Reference Level OR
there are observable deterministic effects excluding transient erythema
4.1 Radiotherapy pre-treatment planning scans IF CT planning scan needs to be repeated twice to obtain an appropriate data set (3 scans in total, including the intended scan)
4.2 Radiotherapy treatment verification images Set-up error leads to 3 or more imaging exposures in a single fraction (including the intended image, ie 3 images in total OR when the number of additional imaging exposures is 20% greater than intended over the course of treatment or than was described in the protocol d 
5 Foetal
All modalities
Where there has been a failure in the procedure for making pregnancy enquiries AND the resultant foetal dose is 1mGy or more

Breast feeding infant
Nuclear medicine only

Where there has been a failure in procedure AND the resultant infant effective dose is 1 mSv or more
Radiotherapy delivered dose (including brachytherapy)
7.1 Therapy over-exposure Delivered dose to the planned treatment volume and/or organs at risk is 1.1 or more times (whole course) or 1.2 or more times (any fraction) the intended dose
7.2 Therapy under-exposure Delivered dose to the planned treatment volume is 0.9 or less times the intended dose (whole course) e
Radiotherapy geographical miss (including brachytherapy)
8.1 Total All total geographical misses, even for a single fraction or significant part thereof
8.2 Partial Where the miss exceeds 2.5 times the locally defined error margin f AND the guideline dose factors above (as 7.1 & 7.2) for the PTV or OAR are exceeded
Nuclear medicine therapy
9.1 Selective internal radiation therapy Delivered activity is outside +/- 20% of the prescribed activity
9.2 All other nuclear medicine therapies Delivered activity is outside +/- 10% of the prescribed activity
Complementary notification codes
M More than one individual exposed within the same incident/theme.
(plus suffix with relevant 1 to 9 code)
All cases regardless of dose
E Equipment fault exposure (suffix as above)
V Voluntary notification (suffix as above)
C Clinically significant event (suffix as above)


a  Criteria apply to the total exposure from the incident, including any intended component plus over-exposure and/or necessary repeat exposures. Where a multiplication factor is specified this is defined as the total dose from the incident divided by the intended dose.

b   This column of the table defines the various notification criteria. Where the exposure is not easily estimated in mSv or the dose unit specified, an alternative recognised unit may be applied and specified in the notification.

c  In England, Wales and Northern Ireland, a child is someone who has not yet reached their 18th birthday. In Scotland, this is someone who has not yet reached their 16th birthday.

d  Excluding where there has been no breakdown in protocol and repeat verification imaging has facilitated correction of a ‘setup’ error so preventing a geographical miss in treatment.

e  Excluding where the under-exposure to the target volume is a result of a geographical miss, which is reportable under 8.1 or 8.2.

f   A surrogate for the locally defined error margin might be a displacement of 2.5 times the local imaging action level for specific anatomical site and treatment intent.

Back to significant accidental or unintended exposures (SAUE)

Back to criteria for making a notification

Last updated:
26 January 2021