Boards/Trusts should ensure that if appropriate, this information is passed to ALL persons having the responsibility for premises registered under THE REGISTERED HOMES (NI) ORDER 1992.

SAN(NI)96/9 An Executive Agency of the Department of Health

and Social Services

v

DEFECT & INVESTIGATION CENTRE

FOR ACTION BY: Chief Executive of each HSS Trust General Manager/Chief Executive of each HSS Board General Manager/Chief Executive of each Agency

Stoney Road Dundonald Belfast Northern Ireland BT16 1US

Telephone 01232 523714 Facsimile 01232 523900

GTN Code 440

SAN(NI) 98/60 Date:18 November 1998

TITLE: X-RAY TUBE ANODE STARTER: COMET HS150

HIGH SPEED STARTER USED WITH PICKER GENERATORS INCLUDING TRANSIX 800s, R703, R500 AND R501

1. SUMMARY An incident has been reported in which an HS150 anode braking timer failed, causing the braking

relay to remain closed as long as the unit remained switched on. 2. ACTION The following information should be brought to the attention of all who need to know or be aware of

it. This will include:

Directors of Radiology A&E Directors Radiologists Radiology Business Managers Superintendent Radiographers Radiographers Directors of Nursing Radiation Protection Supervisors Radiation Protection Advisers Medical Physicists EBME Departments Works Staff concerned with maintenance of equipment Supplies Officers Estates/Facilities Managers Safety Liaison Officers Risk Managers

Comet HS150 high speed starters fitted to Picker equipment (formerly GEC Medical) suffer from a risk of

the X-ray tube overheating and oil leaking from the expanding bellows if there is a failure in the anode braking timer. If this happens the equipment will not function and the following action should be taken:

A note should be taken of all settings and read-outs on the control panel, paying particular attention

to any error codes.

The unit should be powered down and those responsible for servicing the equipment should be contacted.

As a general safety precaution:

If any fault has developed the equipment should not be left powered up. If the unit is to be left unattended for any length of time it should be powered down.

Boards/Trusts should ensure that if appropriate, this information is passed to ALL persons having the responsibility for premises registered under THE REGISTERED HOMES (NI) ORDER 1992.

SAN(NI)96/9 An Executive Agency of the Department of Health

and Social Services

v

SAN(NI)96/9

3. BACKGROUND The HS150 anode starter was manufactured by Comet and supplied by Picker with their range of generators. An incident was reported to the Department in which an HS150 anode braking timer failed, causing the braking relay to

remain closed as long as the unit remained switched on. Instead of the usual three seconds of dynamic braking, the supply was continuously applied to the X-ray tube stator.

With the non-functioning unit left powered up, the supply from the braking relay heated the tube. Over a prolonged

period the oil in the tube expanded sufficiently to split the rubber diaphragm in the bellows, allowing hot oil to leak from the tube.

The tube involved in the incident had a thermal cut-out intended to prevent excessive pressure in the tube housing. This

enabled the not ready signal to the generator, inhibiting further exposures. However, it did not cut off the supply to the anode, so the temperature and pressure continued to rise.

These units do not comply with TRS89, which requires that any source of electrical energy must be disconnected, if the

continued application of that energy could result in an excessive pressure in the tube housing. Some of these generators are wired in such a way that further exposures are prevented in an over pressure situation, but the anode braking supply is not cut off.

Picker has been unable to provide a solution that resolves this problem but has been working with Comet on a

modification. This monitors the time that braking is applied and cuts off the supply if the braking relay does not release. Picker will not provide this free of charge but intend to offer it at cost.

Users should consider having the modification fitted to prevent recurrence. Those users who choose not to fit the

modification should attach a warning notice to the unit indicating that power should be turned off whenever the unit is left unattended.

4. ENQUIRIES Enquiries to the manufacturer should be addressed to:

Mr C Bloomfield Picker International Longacres House Norton Green Road Stevenage Herts SG1 2BA Telephone: 01438 311777 Fax: 01438 311888

Enquiries for those units under service contract with IGE should be addressed to: Mr J Lower IGE Medical Systems Limited 352 Buckingham Avenue Slough Berkshire SL1 4ER Telephone: 01753 874000 Fax: 01753 696067 Enquiries for those units under alternative service arrangements should be addressed to the appropriate service agent. Enquiries in writing: regarding this notice should be addressed as follows: NORTHERN IRELAND DEFECT & INVESTIGATION CENTRE (NIDIC) Health Estates Estate Policy Stoney Road Dundonald Belfast BT16 1US marked for the attention of Mr Brian Godfrey Yours faithfully BRIAN GODFREY Defect Centre Manager

HOW TO REPORT DEFECTS

Professional Estate Letter PEL(93)36 issued by Estate Services Directorate, on 27th July 1994 advises Health and Social Services Boards, HSS Trusts and Agencies how to notify HPSS about accidents with and defects in medicinal products,

buildings and plant and other medical and non medical equipment and supplies.