OSCE prep

what are the 4 possible questions for the mobile examination

·        Family members present in bay

·        HCA enters bay whilst exposing

·        Notice primary beam is pointing towards cupboard where staff are working

·        Notice primary beam is facing a corridor where people are passing

TERMINATE EXPOSURE & CHECK THAT NO ONE ELSE IS IN THE ROOM

prevents unnecessary exposure to others, ask someone to hold traffic in corridor, put warning sign on door and lock door

what are the practical steps in the mobile exam?

·        Put lead gown on myself and give one to staff to reduce unnecessary dose

·        As family/friends to leave the room to reduce unnecessary radiation dose

·        180 SID to reduce dose to patient

·        Collimation to reduce dose to patient and scatter. collimate to apices superiorly, t12 inferiorly and lateral soft tissue borders

·        Check direction of primary beam to prevent unnecessary exposure to others

·        Check exposure factors to ensure dose is as low as reasonably practicable. I wont use a high kv technique because i’m not using a grid

·        Check staff extremities aren’t in primary beam to reduce skin dose

·        Stand 2m back to adhere to inverse square law

·        Hang lead up to prevent cracking which would make it less effective radiation safety protection measure the next use

·        Put xray tube away to prevent damage to the tube housing which may cause leaking of radiation/ radiation emission in an unexpected way.

what are the steps for the C arm

·        Lead gown on and fastened on sides

·        Warning sign on door

·        Lock door

·        Put foot pedal in bracket

·        Put key in and turn to green

·        Stand far away and ask people move away and press black button

Data: 1 from baseline is in tolerance, 2 or more isn’t in tolerance

CT - what is mA modulation?

Using the initial scout views the CT system calculates the
optimum mA for the patient anatomy that is included in each CT “slice”.

For mA modulation to be accurate the patient must be positioned at the isocentre of the gantry. Care should be taken to remove artefacts (spectacles/dentures/belts/clothing, etc.) and to position anatomy that doesn’t need scanning out of the scan field of view, e.g. during a chest scan the arms should be placed above the patients head. This is so the CT system does not include the arms within its mA calculations as it would increase patient dose.

CT - what are DRLs

Diagnostic reference levels are benchmarks of patient dose for standard sized patient. First step in optimisation process. Can be exceeded for individual exposures but should not be consistently exceeded when groups of exposures are analysed. Local DRL – Set up based on dose data from a hospital or trust. National DRL – Set up based on dose data from hospitals or trusts all over the country.

CT- local rules: what is the controlled radiation area

The Ionising Radiation Regulations (2017) require that a Controlled Radiation Area be established in areas where specific radiation levels could be exceeded. These Local Rules are designed to minimise the possibility of unintended irradiation or of excessive doses being received by anyone in the CT scanner area. Access to the room is restricted to the persons explained below. The CT scanner room beyond the shielded door is a Controlled Radiation Area when the room warning signs are illuminated at the door. This is the case whenever the mains electrical supply is switched on to power the CT scanner and control computer. Entry to authorised persons is only allowed when the red ‘DO NOT ENTER’ SECTION IS not
illuminated.

CT- local rules: ACCESS TO THE CONTROLLED AREA AND AUTHORISATION TO USE X-RAY EQUIPMENT

Authorisation for access to the room and use of the equipment is restricted to:
a. Trained and authorised Academic Staff members and Clinical Tutors. A list of
authorised persons shall be held by the Head of Department.
b. Students authorised by a member of Academic Staff or Clinical Tutor (who are
themselves authorised). Such authorisations shall be in accordance with the
written requirements of the appropriate training module.
c. Students or visitors under the direct supervision of an authorised Staff member or Clinical Tutor.
d. An agent of the equipment supplier in order to test or repair the equipment. Note
that under this situation control of the facility is passed to the agent of the supplier
and work will be carried out under their local rules.

CT- local rules: maintenance

Only the service agent’s engineers may work on this machine. Repair and maintenance must be documented by the engineer. After a major repair the RPS must be consulted regarding whether, consequently, a critical examination is necessary. Safety controls for staff, the public or patient protection must not be altered without prior risk assessment. Servicing must use the ‘hand-over’ and ‘hand back’ form.

CT- local rules: machine QA

Machine quality assurance (QA) and safety checks must be undertaken by the organisation providing radiation protection services on a regular basis and always following a major component change

CT- local rules: x-ray exposures for non-medical xrays

It is an offence under Ionising Radiation (Medical Exposure) Regulations (IRMER 2017) to expose anyone using this X-ray equipment for the purposes of obtaining a X-ray image, even if the intended purpose is a ‘medical’ image. Any incident of this nature should be reported to the RPS. The RPS and the RPA will then conduct an investigation with the outcome reported to the Head of Department.

CT- local rules: pregnant persons

Any person who is or is likely to be pregnant shall notify the RPS and/or Head of Department before being involved in the use of the CT scanner, and shall comply with any restrictions or monitoring requirements of that RPS. This will allow a risk assessment of their work with radiation sources to be performed so that appropriate control measures can be put in place to ensure their exposure is kept As Low As Reasonably Achievable (ALARA). The dose limit for staff following declaration of their pregnancy is 2mSv to the surface of the abdomen. It is
unlikely that such a dose would be received by anyone working on this machine. As a general rule, any person who is pregnant must not enter the CT scanner room without prior approval of both the RPS and the RPA.

CT- local rules: what are the safe systems of work?

In following these instructions, Academic Staff, students and Clinical Tutors will not receive any significant radiation dose. Nevertheless, these persons must comply with any dose monitoring requirements specified from time-to-time by the RPS or the RPA.
1. When staff and/or students are working within the CT scanner room, the door to
that room should be left open to prevent anyone else from initiating irradiation.
2. When exiting the CT scanner room to initiate irradiation, the last person to leave the room shall ensure that there is no-one inadvertently left in the room before they
close the interlocked door and initiate exposure.
3. Before initiating an X-Ray exposure, the person initiating the exposure shall:
a. Ensure that only relevant persons are present.
b. Ensure that the scanner door is closed
c. Ensure that no-one is in the CT scanner room
d. Ensure that the controlled area light is illuminated
4. During X-Ray exposures the person initiating exposure shall check that the red “do not enter” light is illuminated and that no-one attempts to enter the CT scanner room until irradiation is terminated. Should the equipment fail to terminate the exposure upon completion, then use the emergency stop button.
5. After a session of use or when leaving the equipment unattended for a period of time, ensure that the equipment is left in a safe condition and that the CT control room door is closed and locked (by keypad). Safe condition means that the equipment is not in a state to readily initiate exposure.
6. Contact an RPS named below immediately and do not proceed to use the CT
Scanner if:
a. It is thought that anyone may have been exposed to radiation.
b. You have any suspicion that the CT scanner unit, door interlocks or warning
lights are not functioning correctly.
c. You have any queries as to operation of the equipment or are unsure or
what action to take.

CT- local rules: what is the dose investigation level

The University of Liverpool has set an Investigation Level of Effective (whole body) Dose of 2mSv per annum. It is highly unlikely that any members of staff or students will receive this level of dose from working with the CT scanner.

CT - local rules: what are the emergency procedures/contingency plans

If the machine fails to terminate normally or there appears to be a serious machine
malfunction operate the nearest emergency stop button. In cases of possible fire (smoke or fumes from the machine), electrical or other potentially major hazards isolate the equipment. Place the notice ‘machine faulty do not use’ on the control console. Report the problem to the RPS. The machine must be checked by an X-ray engineer and by the RPS before being returned to service. In case of Fire follow the University’s fire plan.