Radiotherapy Physics Interview Questions & Answers

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About this NHS interview question bank

To prepare for a radiotherapy physics NHS interview, expect questions on plan checking, linac quality assurance and machine faults, independent dose verification, IR(ME)R and incident reporting, commissioning new techniques and how you work with therapeutic radiographers and clinical oncologists. Build short spoken answers around real moments from your training or practice, and know your HCPC or voluntary register standards, the NHS values and how the department you are applying to delivers its service.

This bank contains 40 original practice questions with first-person model answers written for dosimetrists, clinical technologists and clinical scientists in radiotherapy physics, pitched mainly at Band 6 with a selection for Band 7 clinical scientist and senior dosimetrist posts. It covers treatment planning and plan checking at a principles level, machine QA and faults, independent checks, IR(ME)R duty holders and the MPE role, error reporting, out-of-hours support, data integrity, training STP trainees and research. Every question explains what the panel is really assessing, the points to hit, the mistakes to avoid and the frameworks worth reading, so you can practise answers that sound like you rather than a textbook.

 

What this question bank covers

• Motivation for radiotherapy physics
• NHS values in a technical service
• Plan checking and treatment planning principles
• Linac QA and machine faults
• Independent dose verification
• IR(ME)R duty holders and the MPE
• Radiotherapy errors, near misses and SAUE reporting
• PSIRF and learning
• Commissioning new techniques
• Working with therapeutic radiographers and clinical oncologists
• Out-of-hours physics support
• Data integrity and record and verify
• Patients with implanted devices
• Pregnancy enquiries and safeguarding
• Equality and inclusion
• Training STP trainees
• Research, audit and CPD
• Resilience and wellbeing

 

40 NHS interview questions with full model answers. The first 8 are free to read below. Unlock the remaining 32 for £2.99 (12 months' access).

These are original practice questions written to reflect how NHS interviews are run. They are not leaked or official questions, and Healthcare Interview Prep is independent of the NHS.

 

 

Free NHS interview questions and model answers

 

 

Question 1: Why do you want to work in radiotherapy physics?

Motivation question  ·  Motivation

 

What the interview panel is assessing

The panel wants a genuine reason that connects the physics to patients, not just an interest in equipment or maths. They are listening for some understanding of what the job is day to day, including the checking, the QA and the responsibility that comes with it.

 

Model answer

I'll be honest, I came to it through the physics first. I loved the idea that you could take something as abstract as dose deposition in tissue and turn it into a treatment that cures people. But what actually made me want to do it as a career happened during a placement in a radiotherapy department, when I sat in on a planning meeting for a patient with a head and neck cancer.

The oncologist was trying to keep dose off the parotids and the spinal cord while still covering the target properly, and the dosimetrist was working through the trade-offs with her, very calmly, one structure at a time. Afterwards I went down to the treatment room and watched the radiographers set the same patient up in his mask. He was clearly nervous. It struck me that every decision I'd watched upstairs would end up as something that happened to him, physically, for six or seven weeks. That connection between the numbers on a screen and the person on the couch is what hooked me.

I also like the discipline of it. So much of the job is careful checking: plan checks, morning QA, independent calculations, looking at trends in machine data. Some people find that dull. I find it reassuring, because I know a well-run physics service is one of the reasons radiotherapy in the UK is as safe as it is, and I want to be part of keeping it that way.

And it keeps moving. Techniques like stereotactic treatments, surface guidance and adaptive planning keep changing what we can offer, and physics is right at the front of bringing those in safely. I want a job where I'm still learning in ten years, and where what I learn ends up helping patients directly.

 

Why this answer works

The answer grounds the motivation in a specific, believable moment and links the technical work to the patient experience. It shows realism about the checking-heavy nature of the job and an awareness that physics is central to safety and to bringing in new techniques.

 

Key points to include

• A specific moment that made the role real for you
• The link between physics decisions and the patient on the couch
• Realism about QA, checking and routine work
• Awareness that physics underpins treatment safety
• Interest in new techniques and continued learning

 

Common mistakes to avoid

• Talking only about liking maths or machines
• Giving an answer that could apply to any physics job outside healthcare
• Ignoring patients completely
• Sounding as if routine QA would bore you

 

NHS values and standards

Commitment to quality of care; Improving lives; Working together for patients

 

Further reading

• NHS Constitution for England
• HCPC Standards of proficiency: Clinical scientists
• Towards Safer Radiotherapy (RCR, SCoR, IPEM and partners)

 

 

Question 2: You may not see many patients in this role. How do the NHS values show up in your work?

NHS Values question  ·  NHS Values

 

What the interview panel is assessing

The panel is checking that you understand the NHS values apply to a back-room technical service as much as to a ward. They want concrete behaviours, such as rigour, honesty and teamwork, linked to patient outcomes.

 

Model answer

The six values are working together for patients, respect and dignity, commitment to quality of care, compassion, improving lives, and everyone counts. It's true that in physics a lot of my day is spent with planning systems, QA data and the linacs rather than with patients, but I think the values matter just as much. They just look a bit different.

Commitment to quality of care is the obvious one. When I check a plan, I'm the last technical safeguard before that plan is used to treat someone, possibly for thirty fractions. If I rush it because the list is busy, or tick a box without actually looking at the dose distribution, that's a failure of care, even though the patient will never know my name. So I try to give the tenth plan of the day the same attention as the first.

Working together for patients shows up in how I treat the radiographers and oncologists. If a radiographer rings up because the imaging doesn't look right, I don't want them ever to feel they're bothering physics. Those calls are how problems get caught. During training I made a point of going down to the treatment rooms when I could, rather than just answering on the phone, because it builds the kind of relationship where people speak up.

Respect and dignity and compassion come in when I do meet patients, for example measuring in vivo dose, or explaining to someone with a pacemaker how we'll keep them safe. I try to remember they're often frightened, they may be in a gown, and they're trusting us completely.

And everyone counts reminds me that a patient on a Friday evening, or treated on the older machine, deserves exactly the same standard as anyone else. That's partly why consistent QA and procedures matter so much to me.

 

Why this answer works

The answer names all six values correctly and then translates them into specific physics behaviours. It avoids the trap of saying the values are only for clinical staff and shows that technical rigour is itself a form of patient care.

 

Key points to include

• Name the NHS values accurately
• Link quality of care to careful plan checking and QA
• Show how you support radiographers and oncologists to speak up
• Show compassion in the patient contact you do have
• Consistency of standards for every patient

 

Common mistakes to avoid

• Saying the values are mainly for patient-facing staff
• Reciting the values without examples
• Forgetting the radiographers and wider team
• Being vague about what physics actually does for patients

 

NHS values and standards

Commitment to quality of care; Working together for patients; Compassion; Respect and dignity; Everyone counts; Improving lives

 

Further reading

• NHS Constitution for England
• NHS People Promise
• HCPC Standards of conduct, performance and ethics

 

 

Question 3: During a plan check you find something you think needs changing, but the clinical oncologist is under time pressure and wants it approved today. How would you handle it?

Communication question  ·  Communication

 

What the interview panel is assessing

The panel wants to see that you can raise a technical concern clearly and respectfully with a senior doctor without either caving in or becoming obstructive. They are looking for good judgement about what is safety-critical versus a matter of preference, and knowing when to involve senior physics.

 

Model answer

The first thing I'd do is make sure I'm right and that I can explain it simply. Say I'm checking a lung plan and I notice the target coverage is fine but the spinal cord maximum is over the tolerance in our protocol. Before I pick up the phone I'd recheck the structure, the dose grid and whether the oncologist has already documented an acceptance of that constraint, because sometimes there's a good clinical reason and it's already recorded.

If it isn't documented, I'd speak to the oncologist directly, ideally in person or on the phone rather than just leaving a note in the system. I'd keep it short and factual: 'I'm checking the plan for this patient. The cord max is above our protocol limit and I can't see it documented as accepted. Could you look at it with me?' I'd show them the DVH and where the hotspot sits. Doctors are busy, and I find they respond well when you bring the evidence and a possible solution, for example asking whether the planner could re-optimise with a tighter cord objective without losing coverage.

I'd also be clear about the timeline. If it can be replanned and rechecked before the first fraction, I'd say that. I wouldn't let the pressure of 'approve it today' push me into signing something off that I don't think is safe. If the oncologist decided to accept the dose, that's a clinical decision within their role, but I'd want it documented clearly with their reasoning, and if I still had a genuine safety concern I'd escalate to a senior physicist or the lead for that site.

What I've learned is that it's rarely a conflict if you go in curious rather than accusatory. Most of the time the oncologist says, 'Good spot, let's fix it', and the relationship is better for it.

 

Why this answer works

The answer separates clinical judgement, which belongs to the oncologist, from the physics responsibility to flag protocol deviations. It shows calm, evidence-based communication, a willingness to propose solutions and a clear escalation route if a safety concern remains.

 

Key points to include

• Check your own findings before raising them
• Communicate directly, briefly and with evidence such as the DVH
• Recognise that dose acceptance is a clinical decision that must be documented
• Do not let time pressure override safety
• Escalate to senior physics if a real concern remains

 

Common mistakes to avoid

• Silently approving the plan to avoid friction
• Being confrontational or implying the doctor is careless
• Treating every deviation as a hard stop without considering clinical reasons
• Failing to document the outcome

 

NHS values and standards

Working together for patients; Commitment to quality of care; Respect and dignity; HCPC Standards of conduct, performance and ethics

 

Further reading

• Ionising Radiation (Medical Exposure) Regulations 2017 and employer's procedures
• Towards Safer Radiotherapy
• HCPC Standards of proficiency: Clinical scientists
• Departmental planning and dose constraint protocols

 

 

Question 4: How do you build a good working relationship with the therapeutic radiographers on the treatment units?

Teamwork question  ·  Teamwork

 

What the interview panel is assessing

The panel wants to know you value radiographers as expert colleagues and understand that they are often the first to spot a problem. They are listening for practical habits that make radiographers comfortable contacting physics.

 

Model answer

I think it starts with respect for what they do. Therapeutic radiographers are the ones who see every patient every day, they know the machines' quirks better than almost anyone, and they're usually the first people to notice when something isn't right. If I come across as the physicist who knows best, I'm cutting off one of the most important safety nets the department has.

In practice, a few things have worked for me. When I'm on the QA rota and doing early morning checks, I make a point of chatting to the radiographers coming on shift and telling them how the machine looks, not just leaving the result in the log. If there's a borderline result I'm monitoring, I'll tell them what I'm watching for and what to call me about. It means they're not surprised later.

When they ring physics, I try to answer in a way that makes them glad they called, even if it's a false alarm. I remember a radiographer phoning during my training because the daily output check device was reading slightly differently from usual. It turned out to be the device rather than the linac, but the way my supervisor thanked her and explained what we'd found stuck with me. People keep ringing if you treat them like that.

I also try to understand their side. A breakdown at half past two with a full list means patients waiting, transport issues and a lot of pressure on them. So when I'm dealing with a fault I give them realistic updates on timings, so they can manage patients properly, rather than leaving them guessing.

And I'm happy to learn from them. Some of the best questions I've had about imaging and set-up came from radiographers, and they've made me a better physicist.

 

Why this answer works

The answer shows humility and practical habits, such as sharing QA information and giving realistic updates during faults. It recognises radiographers as safety partners and shows understanding of the operational pressure on treatment units.

 

Key points to include

• Respect radiographers' expertise and daily patient contact
• Share QA findings and what to look out for
• Make it easy and positive to call physics
• Give realistic updates during faults
• Be willing to learn from them

 

Common mistakes to avoid

• Describing radiographers as just the people who operate the machines
• Only communicating through logs and emails
• Making people feel foolish for raising false alarms
• Ignoring the impact of downtime on patients and lists

 

NHS values and standards

Working together for patients; Respect and dignity; Commitment to quality of care

 

Further reading

• Towards Safer Radiotherapy
• HCPC Standards of conduct, performance and ethics
• Society and College of Radiographers guidance on multidisciplinary working

 

 

Question 5: While you are in the treatment room checking in vivo dosimetry, a patient tells you something that makes you worried about their safety at home. What would you do?

Safeguarding question  ·  Safeguarding

 

What the interview panel is assessing

The panel wants to see that you recognise safeguarding is everyone's responsibility, including physics staff with brief patient contact. They are looking for calm listening, no promises of secrecy, and prompt escalation through the right route.

 

Model answer

I'd stop and give them my attention, even though I'm there for a technical reason. Say I'm placing a diode on an older woman's skin and she says quietly that she's dreading going home because her son 'gets angry' and took her bank card. That's a disclosure that suggests possible abuse or financial abuse, and I can't just carry on and forget it.

I'd listen without pushing for detail, and I wouldn't promise to keep it secret, because I may need to share it to keep her safe. I'd say something like, 'Thank you for telling me. I'm going to make sure the right people know so you get some support.' I wouldn't question her or go to her son, because that's not my role and it could put her at more risk.

Straight afterwards, I'd speak to the lead radiographer on the unit, because they know the patient and the treatment team, and together we'd follow the trust's adult safeguarding procedure. That usually means contacting the safeguarding team or the named lead for the department, and the clinical team responsible for her care will be part of that. If I thought she was in immediate danger, for example she said she was scared to leave the building today, I'd make sure that was escalated urgently and not left until the end of the day.

I'd write down what she said, in her words, with the date and time, and keep it factual. I'd make sure it's recorded in the right place as per local policy rather than in a physics QA record.

Afterwards I'd check that it had been picked up. I'll be honest, it would probably stay with me, so I'd talk it through with my supervisor too. In physics we don't get much safeguarding training in context, so I've made sure I've done my trust's mandatory level and know who the leads are.

 

Why this answer works

The answer shows that a physicist with brief contact still has a duty to act. It covers listening, not promising confidentiality, escalating through the radiographer team and safeguarding leads, urgent action if danger is immediate, and factual recording.

 

Key points to include

• Recognise possible abuse, including financial abuse
• Listen calmly and do not promise secrecy
• Escalate promptly via the unit lead and safeguarding team
• Act urgently if there is immediate danger
• Record the disclosure factually in the right place

 

Common mistakes to avoid

• Thinking safeguarding is someone else's job because you are a physicist
• Investigating or confronting the alleged abuser
• Promising to keep the disclosure secret
• Delaying until the end of the day or forgetting to follow up

 

NHS values and standards

Compassion; Respect and dignity; Everyone counts

 

Further reading

• Care Act 2014
• Trust adult safeguarding policy
• Intercollegiate guidance on adult safeguarding roles and competencies
• Mental Capacity Act 2005

 

 

Question 6: Tell me about a mistake you made or a near miss you were involved in, and what you learned.

Patient Safety question  ·  Patient Safety

 

What the interview panel is assessing

The panel wants honesty, ownership and evidence that you reported it and learned from it. In radiotherapy physics they are especially interested in whether you understand how errors are caught by checks, and how systems can be improved.

 

Model answer

During my training I was doing a phantom measurement for a patient-specific QA check on a VMAT plan. The result came out within tolerance, and I was about to record it as a pass. But when I looked at the measurement file properly, I realised I'd exported the plan for the wrong treatment machine in the department. The beam models were very similar, which is probably why it passed, but it wasn't the plan the patient would actually have been treated with.

Nothing had reached the patient, and the plan hadn't been approved for treatment, so it was a near miss. My stomach still dropped, because I knew that a check done on the wrong thing is worse than no check, it gives false reassurance.

I told my supervisor straight away. We repeated the QA properly on the correct machine, which passed, and I completed an incident report on the trust system, because near misses are exactly what the reporting system is for. Our department also feeds that kind of learning into the national radiotherapy error reporting, which I hadn't fully appreciated until then.

What I learned was two things. Personally, I now check the patient, plan and machine identifiers on the QA set-up before I measure, not after. And from a system point of view, we talked about why it happened. The export screen defaulted to the last machine used, and nothing forced you to confirm it. The team added a confirmation step to the procedure and raised it with the software supplier.

It made me realise that most errors in radiotherapy aren't about people being careless, they're about systems that make the wrong thing easy. I'd much rather work somewhere that reports and learns openly than somewhere where people hide near misses.

 

Why this answer works

The answer gives a realistic, low-harm physics example and owns it without excuses. It shows prompt disclosure, reporting of a near miss, a personal change in practice and a system fix, reflecting a just and learning culture.

 

Key points to include

• Choose a real, proportionate example
• Take ownership and report promptly, including near misses
• Explain what you did to make it safe
• Show personal and system learning
• Reflect a just, open reporting culture

 

Common mistakes to avoid

• Claiming you have never made a mistake
• Choosing an example with no real learning
• Blaming the software or a colleague
• Forgetting to mention reporting

 

NHS values and standards

Commitment to quality of care; Working together for patients; HCPC Standards of conduct, performance and ethics: openness

 

Further reading

• Patient Safety Incident Response Framework (PSIRF)
• Towards Safer Radiotherapy
• UKHSA radiotherapy error and near miss reporting guidance
• HCPC Standards of conduct, performance and ethics

 

 

Question 7: Talk us through how you would check a treatment plan. What are you looking for?

Clinical Scenario question  ·  Clinical Scenario

 

What the interview panel is assessing

The panel wants a systematic, safety-focused approach that covers both the data and the dose, not just a glance at the DVH. They are listening for awareness of common failure points such as wrong dataset, laterality, prescription and transfer to record and verify.

 

Model answer

I'd follow the department's plan check procedure and checklist, but the way I think about it is in layers: is it the right patient and the right intent, is the plan clinically acceptable, is it deliverable, and has it been transferred correctly.

First, identity and intent. I check the patient details, the CT dataset and its date, especially if there's been a rescan, and that the prescription in the plan matches the signed prescription: dose, fractions, site and laterality. I look at any previous radiotherapy or special notes, such as a pacemaker or pregnancy status, because those change the checks needed.

Next, the dose. I look at the target coverage against our protocol, the organ at risk doses against the constraints, and I scroll through the distribution slice by slice rather than trusting the DVH alone, because the DVH won't tell you a hotspot is sitting somewhere silly. I check the isocentre position makes sense relative to the anatomy and any reference marks, and that the outlines look sensible, without straying into the clinician's role on contouring.

Then the physics of the plan. The right machine, energy and algorithm, the calculation grid, any density overrides and why they're there, the couch and immobilisation included properly, bolus if it's needed, and whether the monitor units look sensible for the field size and depth. For modulated plans I'll look at how complex it is and whether patient-specific QA or an independent calculation is required by our procedure.

Then an independent dose check, using whatever system the department uses, with the result within the agreed tolerance.

Last, the transfer. I check what's in record and verify matches the approved plan, including imaging set-up and any shifts. A perfect plan is no use if the wrong version goes to the machine.

If anything doesn't make sense, I don't sign it, I ask. And I'm careful not to let fatigue turn it into a box-ticking exercise.

 

Why this answer works

The answer gives a clear structure that the panel can follow and covers the classic sources of radiotherapy error. It balances clinical acceptability with physics checks and transfer, and stays within scope by respecting the clinician's role on contouring and prescription.

 

Key points to include

• Follow the departmental checklist with a clear structure
• Check patient, dataset, prescription and laterality
• Review the dose distribution, not just the DVH
• Check machine, energy, algorithm, MU sense and deliverability
• Include independent verification and record and verify transfer

 

Common mistakes to avoid

• Only mentioning DVH constraints
• Forgetting dataset, prescription or laterality checks
• Ignoring the transfer to record and verify
• Implying the checker should re-contour or change the clinical intent

 

NHS values and standards

Commitment to quality of care; Working together for patients

 

Further reading

• Ionising Radiation (Medical Exposure) Regulations 2017
• Towards Safer Radiotherapy
• IPEM Report 81: Physics aspects of quality control in radiotherapy
• Departmental plan checking procedures

 

 

Question 8: How do you keep up to date and meet the standards of your professional register?

Professional Development question  ·  Professional Development

 

What the interview panel is assessing

The panel is checking that you understand your regulatory or registration obligations and treat CPD as real learning, not a paperwork exercise. They want to hear about varied, reflective CPD linked to your practice and patients.

 

Model answer

It depends a little on your route, so I'll explain mine. I'm a dosimetrist, and dosimetry isn't a profession regulated by the HCPC, so I've registered voluntarily with the Register of Clinical Technologists. That means signing up to its standards of conduct and proficiency and keeping my CPD current. Clinical scientists in the team are statutorily registered with the HCPC, and their CPD standards are similar in spirit: keep a continuous, up-to-date record, use a mix of activities, show it improves your practice and benefits service users, and be ready to submit a profile if you're selected for audit. Whichever register you're on, I think the principle is the same, and I try to work to that standard.

Practically, I try to learn from a mix of places. I go to the departmental physics meetings and any incident learning sessions, because they're often the most relevant thing I'll hear all month. I read the IPEM journal and the radiotherapy safety reports UKHSA publishes, and I've been to IPEM and regional meetings when I can. I also learn a lot from doing, for example when I was involved in commissioning a new independent dose check system, I read the vendor documentation alongside published commissioning approaches and wrote up what I'd learned.

The bit I've got better at is reflection. Rather than just listing 'attended a talk', I write a few lines on what I'll do differently. After a session on surface guided radiotherapy, I reflected on how it changes what a radiographer sees at set-up and what that means for the QA we do.

I also take my wider professional duties seriously. If I'm unwell or out of my depth, I'll say so, because every set of professional standards is clear that you work within your scope. Keeping up to date isn't really about the register for me, it's about not becoming the person whose knowledge stopped the year they qualified.

 

Why this answer works

The answer explains accurately that clinical scientists are HCPC registered while dosimetrists use voluntary registers, and gives concrete, varied, reflective CPD examples. It links learning to patient benefit and working within scope.

 

Key points to include

• Know your register's standards, including CPD and audit
• Recognise the difference between HCPC registration and voluntary registers
• Use a mix of learning activities
• Reflect on what changes in your practice
• Link CPD to patient benefit and scope of practice

 

Common mistakes to avoid

• Saying CPD is just mandatory training
• Being unclear about which body regulates you
• Listing courses without reflection
• Forgetting the CPD audit requirement

 

NHS values and standards

Commitment to quality of care; Improving lives; HCPC Standards of continuing professional development

 

Further reading

• HCPC Standards of continuing professional development
• HCPC Standards of proficiency: Clinical scientists
• HCPC Standards of conduct, performance and ethics
• IPEM CPD guidance
• Register of Clinical Technologists standards

 

 

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