NHB024 Radiation Risk Assessment V1.1 17.04.20

Radiation Risk assessment – Ionising Radiations Regulations 2017

Version date: 11/04/2020 RRPPS, University Hospitals NHS Foundation Trust, 0121 371 7000 Radiation Risk Assessment, Page 1

This radiation risk assessment is carried out in accordance with the requirement of Regulation 8(1) of IRR 2017. It does not apply to the person undergoing the x-ray imaging procedure, but it does apply to (a) staff carrying out exposures, (b) members of the public and (c) other persons.

A. Risk Assessment Assessors Assessor Anita Jefferies Job Title Head of RRPPS, RPA Signature Date 17/04/2020 Assessor Peter McGookin Job Title Clinical Scientist Signature Date 17/04/2020

Date of next review Review workload and staffing after 1 month

B. Employer, Location and Activity Details Employer University Hospitals Birmingham NHS Foundation Trust

Site Address Nightingale Hospital, NEC Birmingham Department Imaging Work location Wards and general x-ray room Work Activity The Nightingale Hospital at the NEC will contain a series of 124-bed wards, with a total capacity of up to 4000 beds. The hospital will be run as part of University Hospitals

Birmingham NHS Foundation Trust. The work with ionising radiation in the hospital is:

• Mobile radiography on the wards using mobile DR X-ray systems. The anticipated workload is 0.5 chest x-ray per bed per day (confirmed by Bill Norton) • Mobile radiography in a purpose-built, unshielded “small” x-ray room, for mixed exposures including chest, abdomen, hips, pelvis and extremeties • General radiography using a fixed “u-arm” system in a dedicated, shielded “large” x-ray room

The wards are made up of bays 3.5m wide by 2m deep in blocks of 2 back-to-back rows of six bays (see Figure 1). There is a 1m space between the backs of the bays and approximately 6m between the fronts. The cubicle barriers do not provide shielding. The solid parts of the cubicle are approximately 1m or 1.5m high, allowing visibility all around (see Figure 2). There is a solid weightbearing floor. There will be 4 mobile x-ray systems per 496 beds. Each mobile will be staffed by 2 radiographers per shift. The service will be provided on a 24 hour basis covered by radiographers each working 37.5 hrs per week in a combination of three different shift patterns: 8am-8pm, 8pm-8am and 9am-5pm. 90% of the x-ray work is expected to be performed during the 8am-8pm day shift. There will also be 1 CT scanning facility on site provided and staffed by Cobalt Health using their mobile CT trailer located in an area away from the wards. Use of CT scanning facility is covered in a separate risk radiation assessment. The small x-ray room is 4m x 5m and will be used as needed for imaging of ambulant patients. It is situated against an external wall, with three unshielded walls, one of which adjoins an ultrasound room.

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The large x-ray room is 6m x 4.5m and will be used as a general x-ray room. It will contain a u-arm system. One wall is solid block, two walls and the door are shielded with code 5 lead, and the remaining wall is 25mm plasterboard. This risk assessment considers a hypothetical radiographer involved in every chest x-ray in three 8am-8pm day shifts per week for one year at full capacity. In practice each radiographer’s radiation exposure will be significantly lower because of the different shift patterns and changing workloads. Some x-ray mobiles may come supplied with remote exposure control. This will not be used and will be removed from the units on acceptance to prevent inadvertent exposures due to interference or more than one unit working on the same frequency.

Manager 1 Job Title

Email

Tel

Tina Jones Acting Group Manager – Imaging and Medical Physics tina.jones@uhb.nhs.uk 07500 606409

Manager 2 Job Title

Email

Tel

Bill Norton Head of Department, Imaging bill.norton@uhb.nhs.uk 0121 371 2302

Manager 3 Job Title

Email

Tel

Pauline Gray Deputy Head of Department, Imaging pauline.gray@uhb.nhs.uk 0121 371 4291

C. Source of Ionising Radiation and Nature of Hazard [IRR17 ACOP Reg. 8, paragraph 70 (a, k)] Source Mobile general digital radiography x-ray systems

General digital radiography x-ray system Min. kVp:

Typical CXR kV: Typical XR Abdo kV:

40 90 80

Max. kVp. 150

Hazard External x-ray exposure from scatter and leakage

Foreseeable radiation accident

situations

Situations

Control measures /Contingency plans in place?

Failure of exposure to terminate, e.g. failure of exposure button to release. Addressed in Local Rules Unauthorised entry into Controlled Area Addressed in Local Rules Inadvertent activation of exposure control Addressed in Local Rules Failure to collimate Addressed in Local Rules Failure to wear correct personal protective equipment where required Addressed in Local Rules

Remote exposure control inadvertently activated Addressed in Local Rules

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D. Estimates of Dose / Dose Rate [IRR17 ACOP Reg. 8, paragraph 70 (b)] – Input from Medical Physics Expert (MPE) is required

Location Exam Type kV

Typical primary beam O/P @ 1m

(µGy/mAs)

Maximum scatter factor (µGy/Gycm²) Situation

DAP NDRL (Gycm²)

Distance (m)

Max scatter air kerma per single exam (µGy)

With 0.25mm Pb apron

(µGy)U-Arm X-Ray Chest AP 90 66.9 5.29 Single Exam 0.15 1 0.79U-Arm X-Ray Chest AP 90 66.9 5.29 Radiographer single exam 0.15 2 0.20 0.02U-Arm X-Ray Chest AP 90 66.9 5.29 Single Exam 0.15 1 0.79U-Arm X-Ray XR Abdo 80 53.2 4.98 Single Exam 2.5 1 12.45U-Arm X-Ray Chest AP 90 66.9 5.29 Supporting patient 0.15 0.5 3.17 0.26U-Arm X-Ray XR Abdo 80 53.2 4.98 Unauthorised entry 2.5 0.5 49.80U-Arm X-Ray XR Abdo 80 53.2 4.98 Inadvertant activation of exposure 2.5 0.5 49.80U-Arm X-Ray Chest AP 90 66.9 5.29 Failure of exposure to terminate 15 2 19.84 1.61U-Arm X-Ray Chest AP 90 66.9 5.29 1 failure of e-stop 4.5 2 5.95 0.48

Chest AP 90 85.7 5.29 Staff in adjacent bay 0.15 2 0.20XR Abdo 80 68.1 4.98 Staff in adjacent bay 2.5 2 3.11

* O/P taken from Samsung DR at TST Failure to terminate is 100xintendedFailure of e-stop is 30xintended

Apron doses are based on Max Scatter - transmission of 0.081 used (0.25mmPb)

Location Exam Type kV

Typical primary beam O/P @ 1m

(µGy/mAs)

Maximum scatter factor (µGy/Gycm²) Situation

DAP NDRL (Gycm²)

Distance (m)

Max scatter air kerma per single exam (µGy)

With 0.25mm Pb apron

(µGy)Mobile Bed Bay Chest AP 90 82.2 5.29 Single Exam 0.15 1 0.79Mobile Bed Bay Chest AP 90 82.2 5.29 Radiographer single exam 0.15 2 0.20 0.03Mobile Bed Bay Chest AP 90 82.2 5.29 Radiographer single exam 0.15 3 0.09 0.01Mobile Bed Bay Chest AP 90 82.2 5.29 Single Exam 0.15 1 0.79Mobile Bed Bay XR Abdo 80 67.1 4.98 Single Exam 2.5 1 12.45Mobile Bed Bay Chest AP 90 82.2 5.29 Supporting patient 0.15 0.5 3.17 0.26Mobile Bed Bay XR Abdo 80 67.1 4.98 Unauthorised entry 2.5 0.5 49.80Mobile Bed Bay XR Abdo 80 67.1 4.98 Inadvertant activation of exposure 2.5 0.5 49.80Mobile Bed Bay Chest AP 90 82.2 5.29 Failure of exposure to terminate 15 2 19.84 1.61Mobile Bed Bay Chest AP 90 82.2 5.29 1 failure of e-stop 4.5 2 5.95 0.48Mobile Bed Bay Chest AP 90 82.2 5.29 Staff in adjacent bay 0.15 2.05 0.19Mobile Bed Bay XR Abdo 80 67.1 4.98 Staff in adjacent bay 2.5 2.05 2.96* O/P taken from commissioning survey at Nightingale Failure to terminate is 100xintended

Failure of e-stop is 30xintendedApron doses are based on Max Scatter - transmission of 0.081 used (0.25mmPb)

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E. Estimated Annual Doses and Risk for routine and accident situations [IRR17 ACOP Reg. 8, paragraph 70 (a, b, d, k, l)] Results of previous personal and area monitoring – quote (i) annual dose for the majority of people in that staff group and (ii) the highest annual dose Personal monitoring data for core services radiographers :

Year Staff group Body annual dose Eye annual dose Extremity annual dose Area Monitoring 2017 Radiographer Majority: <0.6 mSv (max: 0.6 mSv) Not monitored Not monitored n/a

2018 Radiographer Majority: <0.6 mSv (max: 0.6 mSv) Not monitored Not monitored n/a

2019 Radiographer Majority: <0.6 mSv (max: 0.6 mSv) Not monitored Not monitored n/a

Number of examinations, bays (per mobile): • 3 active mobiles per 496 bed (plus one on charge); • 1 chest ray per patient every 2 days: 250 per day; • 84 chest x-rays performed per day per mobile; • 90% performed in day shifts: 76 per shift; • 11,500 in 12 months

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Use data in Secton D and information in this section to estimate annual doses Hazard: External x-ray exposure Estimated dose per annum [mSv]

Situation Category Person Category Likelihood Severity Risk Body Eye Extremity

Routine situation Radiographer / HCA at 2 m, wearing 0.25 mm Pb apron* 5 1 5 <0.2 <4 <4

Routine situation Radiographer / HCA at 3 m, NOT wearing lead apron* 5 1 5 <1.7 <1.7 <1.7

Routine situation Other staff working on ward 3 1 3 <0.2 <0.2 <0.2

Routine situation Other person in the basement 3 1 3 0 0 0

Routine situation Person (wearing 0.25 mm Pb apron) supporting patient 10 times a year 3 1 3 <0.003 <0.05 <0.05

Unauthorised entry into Controlled Area 1 time during year at 0.5 m, no PPE (XR Abdo) 1 1 1 <0.05 <0.05 <0.05

Failure of exposure to terminate

Radiographer 10 non-termination incidents in year (CXR), in addition to routine workload 1 1 1 <0.02 <0.3 <0.3

Failure of e-stop

Radiographer 1 e-stop failure incidents in year (CXR), in addition to routine workload 1 1 1 <0.006 <0.006 <0.006

Exposure with no collimation

Radiographer 1 incidents in year (CXR), in addition to routine workload Other person in the adjacent bay, unshielded, 1 incident (CXR)

Other person in the opposite bay, 1 incident (CXR)

Person in the basement 1 incident(CXR)

1 1 1

<0.001

<0.001

<0.0001

0

<0.001

<0.001

<0.0001

0

<0.001

<0.001

<0.0001

0 Inadvertent activation of

exposure control Radiographer or other in bay (not patient) unshielded at 0.5 m, (XR

Abdo) 3 1 3 <0.08 <0.08 <0.08

Staff present in adjacent bays

10 times per year no PPE (10CXR, 1 abdo) 1 1 1 <0.02 <0.02 <0.02

Adjacent patients 3 week stay 4 1 4 <0.005 <0.005 <0.005

*based on one radiographer working 3 day shifts (12 hours) a week for one year

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Likelihood

score

1 2 3 4 5

Descriptor

Rare Unlikely Possible Likely Almost

certain

Frequency

Not expected to occur for

years

Expected to occur at least

annually

Expected to occur at least

monthly

Expected to occur at least

weekly

Expected to occur at least

daily

Severity

score

Descriptor

1

Low level exposure → Designation of Supervised or Controlled Area may need to be considered

2

Unlikely to exceed dose investigation levels → Designation of Controlled Area necessary

3

Likely to regularly exceed dose investigation levels → Controlled Area essential; Designation of Classified Person should be considered

4

Likely to require classification → Controlled Area essential; Designation of Classified Person necessary

5

Possibility of exceeding a dose investigation level by a significant amount → Controlled Area essential; Designation of Classified Person essential

Likelihood

Risk Consequence 1 Rare 2 Unlikely 3 Possible 4 Likely 5 Almost Certain

5 Catastrophic 5 10 15 20 25

4 Major 4 8 12 16 20

3 Moderate 3 6 9 12 15

2 Minor 2 4 6 8 10

1 Negligible 1 2 3 4 5

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F. Control Measures [IRR17 ACOP Reg. 8, paragraph 70 (e, f, g, i, j, m)] Assessment of requirement for protective screen, PPE and personal monitoring is based on dose and doserate considerations detailed in Sections D and E above.

Protective screen Personal Protective Equipment (PPE) Routine Personal Dose Monitoring

Person Group Pb apron Thyroid shield Eye Glasses Body Collar Eye Extremity

Radiographer / HCA

Not required Not required Not required Not required Monthly Not required Not required Not required

Other staff on ward

Not required Not required Not required Not required Not required Not required Not required Not required

Discussion - PPE: Estimated operator doses in section F are worst-case and in reality are likely to be significantly lower, as workload will be shared between operators and the hospital is not intended to be open for a full year. A more realistic case would be:

• Workload shared between 2 radiographers – apply factor of 0.5 • Each radiographer works 50% at Nightingale – apply factor of 0.5 • Nightingale remains open for 6 months – apply factor of 0.5

These factors combined would bring the estimated annual operator dose to 0.2mSv

Operators are receiving the radiation doses during employment so have a dose limit of 6mSv. When weighed up against the physical demands of wearing radiation PPE 8 hours a day, the estimated doses are considered as low as reasonably practicable.

Discussion – monitoring: Where staff are issued with radiation monitors by their own employers, they will continue to wear them during work at the nightingale. Separate monitors are not considered practicable or necessary, for a number of reasons:

• Logistics: there is expected to be a high turnover of a large number of staff and the difficulties of ensuring correct issue and return of monitors are substantial when considered alongside all the other challenges of this project

• Measurement thresholds: because of the high turnover and low doses involved, staff are unlikely to receive doses above the measurement threshold of the monitors if they are worn only during their time at the Nightingale.

• Environmental monitoring: there will be dosemeters on the mobile equipment and the walls of the x-ray room. In the unlikely event of a significant accidental dose being received, the results from these monitors will be used to investigate whether the dose was received at the Nightingale facility or at the operator’s “home” site.

These considerations are in line with British Institute of Radiology guidancei and associated commentii.

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Once one ward is operating at full capacity, electronic personal dosimeters will be issued to certain staff in order to confirm the assumptions used in this risk assessment.

To be completed by Local manager / Lead / RPS

Control Measure Detail of Control Measure In Place? (Y/N)

Add Comments if needed

Bays

Designated areas Temporary controlled area to be designated 2 m around patient and x-ray tube for CXR exposures Y

Restricting access to areas where dose rates are likely to be significant

Switch off equipment when not in use for extended periods Remove key / log-off system when not in use System not in a state ready to expose when unattended Operator to check that no staff in adjacent cubicles prior to exposure Radiographer to give verbal warning and then countdown to exposure

Y

Engineering controls Pause/abort/stop/emergency stop buttons Shielding, collimation, filtration Remove remote exposure controls from x-ray systems

Y

Small x-ray room

Designated areas Temporary controlled area to be designated 2 m around room Y

Restricting access to areas where dose rates are likely to be significant

Warning notice on door Switch off equipment when not in use for extended periods Remove key / log-off system when not in use System not in a state ready to expose when unattended Operator/assistant to ensure that no staff are within 2m of room during exposure

Y

Engineering controls Pause/abort/stop/emergency stop buttons Shielding, collimation, filtration Remove remote exposure controls from x-ray systems

Y

Large x-ray room

Designated areas Controlled Area: Entire x-ray room – Sign of Controlled Area and Name of RPS n/a – room not yet built

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Restricting access to areas where dose rates are likely to be significant

Switch off equipment when not in use for extended periods System not in a state ready to expose when unattended When exposing, ensure operator can see all entrances and/or have means to restrict access.

n/a – room not yet built

Engineering controls Pause/abort/stop/emergency stop buttons Shielding, collimation, filtration Warning lights and notice on door

n/a – room not yet built

General

Planned system of work, Local Rules (LR) and Contingency Plan

• Local Rules and exposure protocols in place

Y

RPSs appointed in writing • Signed copy readily available Y

Equipment critical examination and acceptance testing • Equipment to be installed by engineer and acceptance tested prior to going into clinical use Y

Staff training, inc. radiation safety training, safe use of equipment, Apps training, QA

• All operators trained on radiation safety • Training on safe use and maintenance of equipment • Operators trained to use equipment correctly (for clinical protocols and for QA)

Y

Equipment maintenance

• The equipment maintenance contract is with Samsung • The frequency of servicing is 2 per year • The contract is in place for 12 months initially • Equipment fault log book or equivalent – record kept electronically on Your Imaging

Y

Equipment radiographer’s QA and physicist’s QA

• Radiographer QA arrangements: Periodic tests using Cu filter – results kept electronically on Your Imaging • Physics QA arrangements: Annual routine plus callout as required

Y

Personal protective equipment (PPE) • Adequate Pb equivalent: 0.35mm lead equivalent aprons and thyroid shields Y

PPE screening programme • PPE was screened in January 2020. Items to be logged with unique ID.

Classification and monitoring of persons

• Designation of classified persons (IRR17 Reg. 21) necessary? |No • Radiographers and HCAs monitored by “home” Trust • Environmental monitoring on mobile equipment and walls of x-ray rooms - monthly • Electronic personal dosimeters for selected staff

Y

Other • Periodic checks of correct functioning of emergency stop buttons Y

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G. Actions

Action No. Action to be undertaken Name of person responsible Target Date Date completed Signatory

1. Provision of controlled area signs RRPPS 20/04/2020

2. Provision of electronic personal dosemeters RRPPS When ward at full capacity

RRPPS, University Hospitals NHS Foundation Trust, 0121 371 7000 Version date: 11/04/2020 Radiation Risk Assessment, Page 11

Appendix Figure 1. Example Ward Layout

RRPPS, University Hospitals NHS Foundation Trust, 0121 371 7000 Version date: 11/04/2020 Radiation Risk Assessment, Page 12

Figure 2. Photograph of ward, Hall 12

i UK guidance on the management of personal dosimetry systems for healthcare staff working at multiple organizations. Rogers Andy, on behalf of the British Institute of Radiology, Chapple Claire-Louise, Murray Maria, Platten David, and Saunderson John. The British Journal of Radiology 2017 90:1079 ii Co-operation of employers in the area of personal monitoring: a commentary on BIR guidance on the UK regulatory situation. RogersAndy. The British Journal of Radiology 2017 90:1079