Adapting to a new way of treating

Dr Ben George

Over the last 18 months, GenesisCare has treated more than 170 patients on the UK’s first ViewRay MRIdian MR-linac and adopted SMART planning as a new way of working. Here, Ben George explains why this latest hypofractionated technique has proven to be one of the success stories of the COVID-19 era.

Stereotactic ablative radiotherapy (SABR) is growing in importance in the curative cancer pathway. Increasingly, it offers patients the opportunity to enjoy relatively long periods of disease control where previously they would have been considered for palliative treatments. During COVID-19, the scales have tipped even further in favour of hypofractionated techniques because protocols have been revised to limit the risk of patient infection. More recently, attention has turned to stereotactic ablative MR-guided adaptive radiotherapy (SMART) – the most exciting development in radiotherapy for years, with the potential to treat previously inaccessible targets.

GenesisCare has been the first in the UK to adopt SMART, installing the first ViewRay MRIdian MR-linac just over a year ago. Since then, we have treated over 170 patients, some of which are the most challenging in the world from a radiotherapy perspective, such as pancreatic, central lung and now renal cell carcinomas. MRIdian sits within our SABR offering, which is run by a specialist team of oncologists, physicists, dosimetrists, and radiographers. Over an intensive 18 months, we have adopted a completely new way of working and overcome the challenges of a pandemic to treat patients not just from across the UK, but also from around the world.

SMART explained

The MRIdian MR-linac combines a 0.35 T split superconducting magnet with a 6 MV linear accelerator. This gives it unique advantages over conventional external beam radiotherapy linear accelerators, which rely on kV cone-beam CT (CBCT) imaging, and enables an entirely new approach to treatment.

First, using MRI instead of CBCT provides superior soft-tissue visualisation. This increased imaging capability allows the treatment to be adapted at each fraction based on the daily position of the target and nearby organs at risk (OARs). This is in marked contrast to external beam treatment with CBCT, where anatomy captured in the CBCT is simply rigidly matched against a planning CT. This rigid registration is then used to calculate the movements required to shift the patient into the correct position for treatment.

Second, the MRIdian takes images continuously throughout the treatment period to not only monitor the patient position, but also turn the treatment beam on and off. This is carried out as the patient’s anatomy moves through the breathing cycle.

This combination of enhanced visualisation and real-time imaging adds a layer of certainty in the delivery of treatment.

  • The MRIdian on-table adaptive planning system generates a new, optimised treatment plan for each fraction. This accounts for these day-to-day anatomical variations when the patient is in the treatment position.
  • Treatment delivery is then automatically gated so that the dose is only delivered when the target is in the optimal position. The machine is able to monitor every intrafraction motion caused by breathing or organ-filling.

As a result of these factors, we can design plans which deliver a higher dose, more precisely than with conventional SABR. There is no need for invasive fiducial marker insertion and any uncertainty is removed. Moreover, we can reduce planning target volumes, remove internal target volumes, and minimise the amount of tissue irradiated.

SMART has led to a paradigm shift in how some cancers are treated. In particular, it can benefit cancers in areas where there is significant inter- or intrafraction motion of either the target or OARs. Across the global community, MR-linac centres are now treating novel indications, such as renal, central lung and hepatobiliary tumours, and achieving clinical outcomes not previously thought possible. It is not simply a case of improving on an existing treatment – for some tumour types, SMART is facilitating new referral patterns for patients who may not typically be eligible for radiotherapy.

Pancreatic cancer – a new way of treating

Pancreatic cancer is one such example and of all the tumour sites we are now treating at GenesisCare, this is undoubtedly the one that is breaking most ground, offering new hope for both clinicians and patients.

For decades, surgical resection and adjuvant chemotherapy and radiotherapy have been the cornerstones of primary and secondary hepatobiliary tumours and pancreatic cancer treatment. However, options are limited for many patients. Less than 20% are resectable at diagnosis and not all patients are fit enough for an operation or effective chemotherapy regimens. There is, however, emerging evidence of a dose-response relationship, proving that escalated radiation doses are associated with improved local control as well as overall survival in borderline resectable (BRPC) or locally advanced pancreatic cancer (LAPC). Conventional radiotherapy delivers a comparatively homogenous radiation dose to the target volume. In contrast, SABR treatments combine advanced image guidance systems, accurate dose delivery and hypofractionated regimes. This is to facilitate a deliberate heterogeneous dose distribution across the target. This means the radiation tolerances of surrounding OARs are respected, while the tumour receives a higher, ablative radiation dose. A number of SABR studies have yielded good results in the treatment of large hepatobiliary tumours, with 1-year local control exceeding 90% and acceptable toxicity. Furthermore, delivering these hypofractionated ablative doses of radiation over a shorter treatment schedule has the potential to reduce the burden of treatment on patients.

However, with conventional SABR this therapeutic approach is often limited by concerns regarding organ motion and the possibility of developing small bowel radiation toxicity. As a result, many patients are only being treated with systemic agents. This is a prime example of where the elements of SMART on an MR-linac can facilitate an effective radiation dose escalation, while still respecting the radiation tolerance of normal tissues and surrounding OARs. In fact, using an MR-linac, it has been possible to successfully increase the prescribed dose in patients with primary pancreatic cancer. The previous standard dose was 33 Gy in five fractions, but SMART enables us to escalate the prescribed up to 40 Gy or even 50 Gy in five fractions. At the time of writing, 30 patients have been treated on the MR-linac for pancreatic tumours at GenesisCare.

Compassionate Access

The significance of MR-linac as an innovation in cancer treatment can’t be understated and, although at GenesisCare we are offering it in a private setting, we are committed to sharing the benefits of this technology with the wider medical community. Patients with localised pancreatic cancer have variable access to precision radiotherapy in the UK. The n-SARS-CoV-2 pandemic has further disadvantaged this patient group by reducing the availability and safety of surgery and chemotherapy. Considering this, since 2020 GenesisCare in association with GenesisCare Foundation, UK charity, Pancreatic Cancer Research Fund, ViewRay and University of Oxford have been treating NHS patients with localised pancreatic cancer with SMART at no costThe programme, which is run through a partnership with the University of Oxford, is generating preliminary clinical and patient-reported outcome data on a UK cohort. This will inform the design of subsequent randomised clinical trials and help to embed SMART in UK oncology practice.

A new way of working

With any new technology, there comes a learning curve. MR-linac represents a significant change in working practices. It demands a style of inter-disciplinary working which challenges the norms.

In a standard radiotherapy workflow, a patient will receive a treatment planning CT one to two weeks before the start of treatment. During this time, several steps are carried out by a team of dosimetrists, physicists, doctors and radiographers to produce a treatment plan ready for the patient’s first fraction. These steps include contouring the treatment target and OARs and optimising the machine parameters to deliver the prescribed dose to the target while sparing critical structures. This is followed by reviewing the dose distribution, checking the planning process to ensure no errors have occurred and performing an independent dose calculation.

As part of the on-table adaptive workflow, the time taken for this process must be reduced from days to minutes. In order to achieve this, close inter-disciplinary working between the team is required. The need to undertake a number of complex tasks during each adaptive treatment also increases the time for each fraction to around one hour.

The MRIdian workflow involves a Clinical Oncologist on-site during treatment to oversee the daily adaption. To maintain a treatment schedule at GenesisCare, this has meant that clinicians had to be trained to contour all areas of anatomy, often working outside their main area of specialism. Equally challenging was the need to acquire skills in MRI interpretation, which for some specialities is not routinely used as a diagnostic modality. These were all skills that needed to be honed and validated before any patients could be treated on the MR-linac. In our case, we spent many hours learning with colleagues in MR-linac centres of excellence around the world. Twelve months later, we are experts in this field and have treated over 170 patients.

A body of evidence

There is a growing body of data as the global MR-linac community treats ever more and complex cases. We brought this international best practice to GenesisCare and have treated complex and challenging cases, including central lung, pancreas and reirradiation within our first year. We have many case studies available on our website genesiscare.com/mridian/case-studies. We already knew that the technology could deliver, but it was the confidence in our processes and the ability of our team to implement an adaptive workflow in a time-pressured environment, with a patient on the treatment table, which allowed us to embrace the opportunity that MR-linac presents in radiotherapy.

GenesisCare will install the second MR-linac in the UK in 2021. Through our MagNET programme, we are joining with NHS organisations to support education in the use of MR-guided radiotherapy. Enquiries to: James.Good@genesiscare.co.uk

Dr Ben George, Lead Physicist – MR Linac, GenesisCare

Ben is Lead Physicist – MR Linac at GenesisCare UK. He works as part of a multi-disciplinary team which has established a successful and world-leading SABR service delivering complex MR-guided adapted treatments. He has a PhD in Physics with a strong background in computer science, research and clinical computing. He has over ten years of experience as a Clinical Scientist specialising in radiotherapy in both the NHS and the private sector, and as a research scientist for the University of Oxford.

Bringing together Science, Faith and Cancer Care

Slide2

The Revd. Canon Dr. Mike Kirby, Chair of the BIR Oncology and Radiotherapy Special Interest Group, has a wealth of experience as a senior radiotherapy physicist, working on national guidance, developing clinical practice and teaching radiography students. As if this doesn’t keep him busy enough he has also taken on the role of Canon Scientist at Liverpool Cathedral where he is working to encourage dialogue and discussion about science and faith. Here he explains what the role involves.

I began work in the UK’s National Health Service more than 30 years ago, as a Radiotherapy Physicist at the Christie Hospital, Manchester UK.  Alongside my routine clinical work, my main research interest was in electronic portal imaging and portal dosimetry.  I then helped set up Rosemere Cancer Centre in Preston, UK from 1996 as deputy Head of Radiotherapy Physics and Consultant Clinical Scientist there.  During that time I contributed to and edited national guidance documents such as IPEM Reports 92, 93 and 94 and the multidisciplinary work, ‘On-target’.

My work moved back to the Christie in 2007 and as Head of Radiotherapy Physics and Consultant Clinical Scientist for the Satellite Centres, I helped to lead their development in Oldham and Salford as part of the Christie Network. My research and development work has primarily focused on electronic portal imaging, developing clinical practice and equipment development.

Mike Kirby4

More recently my focus has been on teaching and learning for radiotherapy education as a lecturer (Radiotherapy Physics), especially using VERT, for Radiotherapy programmes in the School of Health Sciences, Liverpool University; but always with a focus on the wider picture of radiotherapy development having served on both IPEM and BIR committees throughout my whole professional career.

 

Alongside my scientific work, I am a priest in the Church of England; having trained and studied at Westcott House and the Universities of Cambridge and Cumbria, I hold graduate and postgraduate degrees in Theology.

Mike Kirby

My ministry has mainly been in the Cathedrals of Blackburn, Chester, and Liverpool (Anglican) where I was Cathedral Chaplain.  I have recently (Feb 2020) become a Residentiary Canon of Liverpool Cathedral, with the title of Canon Scientist the primary aim of which is to encourage dialogue and discussion about science and faith.

 I am a member of the Society of Ordained Scientists and have given numerous talks on Science and Faith to schools, colleges, churches and other institutions.  These have included organising lecture series with world renowned speakers at Blackburn (2016) and Chester (2018) cathedrals; a third series was delivered at Liverpool Cathedral in May 2019, and a fourth series is planned for May 2020.

My role is to consider all sciences (physical, clinical, social) in ecumenical and multi-faith environments.  So I will look to work with initiatives already developing in other Christian traditions, other faiths and secular organisations to discuss current challenges, such as climate change, medical ethics, health initiatives and information for cancer, dementia and mental health issues etc..

Mike Kirby2.jpg

My work will be part of the clear faith objectives of the cathedral as a place of encounter for everyone, through events and initiatives within the cathedral, but also beyond.  This will include services focusing on health issues and pastoral challenges (such as bereavement and loss); events engaging with science, its wonders and challenges; fostering further relationships with local and wider communities on science and healthcare education, and with academic and scientific institutions too; encouraging scientific and ethical engagement with schools and colleges, as I have done so previously in both Chester and Blackburn dioceses.

I will be encouraging Christians and Christian leaders to understand science and engage with it more, alongside other national projects such as the recently announced ECLAS (Engaging Christian Leaders in an Age of Science) project of Durham and York universities and the Church of England.  As a self-supporting minister (one whose paid employment is outside of the church), I will also look to encourage and highlight the tireless work of many others who already do this within the diocese and the wider national church.

Within all of this, I have always seen my vocation as being one within God’s service, for all people, with my work for cancer patients being right at the heart of it.

006

If you have any questions for Mike, you can send him an email at sigs@bir.org.uk

Mike is the co-author of the international student textbook on On-treatment Verification Imaging: a Study Guide for IGRT, through CRC press/Taylor and Francis with Kerrie-Anne Calder. They are both contributors to the updated UK national guidance on IGRT due out in 2020.

Mike, with the support of the SIG, has helped to organise a range of events for radiographers, physicists, dosimetrists, radiologists and oncologists. See the full programme here

 

The case of the missing fingers!

NHS

Professor Roger Dale remembers how he got his first job in medical physics and how he thought he’d discovered a radiation martyr.

 

Roger Dale circa 1966

Anxiously seeking a job in medical physics on completion of my first degree in 1966 I quickly became aware that basic grade physicist positions in large centres were difficult to find and, for a while, I was unsure what to do. Being out of work I wrote in some desperation to a (very small) radiotherapy centre in Kent pointing out my predicament and asking if I could join as a porter until such time as I could obtain a physicist position in a larger department. To my great surprise I received a phone call a day or two later from the head radiotherapist (Dr B) inviting me along for an informal chat with him, during which it transpired that the hospital had no requirement for any more porters but did have a vacant establishment for a radiotherapy physicist at principal grade! The principal post had already been offered to a gentleman in New Zealand but it would take a month or two before he could take up the position. Therefore, as there was no physicist in post at that time, Dr B suggested that I join as an acting-temporary(!) basic grade until the principal appointee arrived in the UK. Needless to say, I agreed without hesitation.

The necessary paperwork was sorted out remarkably quickly (the old personnel departments always seemed notably more efficient than the burgeoning HR empires which later followed) and my career in medical physics began, albeit rather shakily. My only ‘supervision’ came from occasional conversations with Mr W, the Chief Technician, whose own duties were entirely focused on running the film badge and thyroid uptake services. He was not at all involved on the radiotherapy side of things so I spent many hours buried deep in the standard radiotherapy physics textbooks of the time. That reading reinforced my desire to stay in medical physics because here were the seemingly abstract physical and mathematical concepts encountered during my degree studies being successfully applied to highly relevant clinical issues. Amongst other things I brushed up on the fundamentals of radium dosimetry, this being necessary since Dr B performed several radium implants each week (remote afterloading systems were only just being introduced back then) and, as I was now the sole medical physicist (of sorts) within a 50 mile radius, he required me to be present during the procedures.

Dr B’s theatre sessions were an eye-opener. Apart from a certain squeamishness at witnessing surgery for the first time, I found his implantation technique quite scary since, although a full range of surgical implements and manipulators were at his disposal, he had a habit of giving all the radium needles a push with his fingers. Worse, it was impossible not to notice that several of his fingers were in fact missing! Even a greenhorn like me knew that physically touching radioactive sources was definitely a practice not to be recommended and the fledgling scientist in me began to ponder on cause and effect.

For several days it worried me that Dr B might be paying a very high price in order to pursue his noble vocation and I was unsure how (or if) I should air my concerns, especially as my status as an unsupervised acting-temporary basic grade physicist of just a few weeks’ standing hardly conferred much authority. Eventually I plucked up the courage to speak to the Chief Technician, telling him how convinced I was that Dr B was suffering radiation damage as a direct result of his operating technique. Mr W’s reaction was not quite what I expected. After some snorts of derision at my expense he then took some delight in pointing out that Dr B had been in the RAMC during the war. He had landed on the Normandy beaches where his jeep had hit a mine, and that was how he had lost several of his fingers. Somewhat chastened, I went away to reflect on the fact that my powers of deductive reasoning might be in need of substantial refinement.

Shortly after this awkward conversation the newly-appointed principal physicist arrived from New Zealand and, contrary to all my expectations, Dr B suggested that I stay on for a while longer to gain some first-hand experience working with the new man. This was to be a tremendous bonus as the knowledge and advice I picked up in the weeks following gave me enough of an advantage to successfully apply for a substantive post (i.e. neither acting nor temporary) in a large London centre, after which I never looked back.

Roger Dale recentToday’s NHS is nothing like the one I joined in 1966 and specialised scientist training is much more formalised and incalculably better. No one these days could be appointed in the manner that I had been but Dr B, like most other NHS professionals then and now, was motivated by good intentions and his thoughtfulness over fifty years ago put me on the path to a rich and fulfilling career in medical physics and radiobiology. I discovered later in life that Dr B had told one of his colleagues that he had helped me because he “wanted to give the lad a chance”. What he gave me was a chance that was truly exceptional and this lad has been immensely grateful ever since.


About Professor Roger Dale

Roger Dale retired from his post at Imperial College Healthcare in 2010 following an NHS career spanning 43 years. His main scientific interest has been the development of radiobiological models which can be used to quantitatively assess the biological impact of radiotherapy and other cancer treatment modalities. He is widely published and the clinical significance of his work has been recognised through the award of a number of prestigious scientific prizes and through his  parallel appointment, in 2005, as Professor of Cancer Radiobiology in the Faculty of Medicine at Imperial College. He continues to be involved in research and teaching.

My first day in radiotherapy physics: reflections of a medical physicist

NHSIn 2010 Karen Goldstone was awarded the MBE for her services to healthcare. Here she reflects on the primitive tools used for radiotherapy patient outlines back in the 1970s and remembers the wise advice she was given on her first day as a radiotherapy physicist.

BIR

I started work in the NHS as a Hospital Physicist in 1970. Prior to that I did the MSc in radiation Physics based at Middlesex Hospital. When doing a placement in nuclear medicine, computer tapes had to be taken to University College about a fifteen minute walk to the other side of Tottenham Court Road and fetched the next day hopefully having run successfully.

In my first post I expected to be doing mainly diagnostic radiology physics but discovered that that was rather a luxury field and so most of my time was spent doing radiotherapy physics. Those were the days when patient outlines were taken using a strip of lead or a flexicurve and planning was done using tracing paper and coloured pencils or biros. There was no computer planning of course and we only had one calculator with a paper roll print out so slide rules were in constant use. The main piece of advice I remember receiving on my first day was that if I discovered I had made a mistake I should own up to it straight away and not seek to cover it up – very wise words.

When not doing radiotherapy physics many hours were spent reading out film densities produced using our homemade “Ardran Cassette” in order to check kVp. This was the beginning of setting up a quality control programme for X-ray units. Another time-consuming activity was sealing lithium borate powder into plastic capsules in order to measure dose to radiologists, carrying out various procedures under fluoroscopic control, and subsequently reading the doses received.

Although diagnostic radiology physics was not seen as important it was an exciting time and I was fortunate enough to hear Godfrey Hounsfield give the 1972 MacRobert Award lecture on “Computerised Transverse Axial Tomography” – an invention that has revolutionised diagnostic imaging.

I started my second post in 1974 in a smaller department but with responsibilities in other, far-flung, hospitals. Here I was the radiotherapy physicist (the only one) and also covered diagnostic radiology and radiation protection, but because it was a smaller department and staff had to be versatile I also did some nuclear medicine and even once some ultrasound.

In the peripheral hospitals in my patch one was still using wet developing, one using just a fluorescent screen for fluoroscopic procedures and one an image intensifier viewed not via a camera but via a mirror arrangement.

How times have changed!


About Karen Goldstone MBE

I worked for forty years in the NHS, in radiotherapy physics, diagnostic X-ray physics and all aspects of radiation protection. In 1983 I set up the East Anglian Regional Radiation Protection Service (EARRPS) based at Addenbrooke’s Hospital in Cambridge, and ran it for almost 30 years. I was both a Radiation Protection Adviser and Laser Protection Adviser. I gave physics lectures to radiologists and was a physics examiner for FRCR both in the UK and Malaysia. With colleagues in EARRPS and Cambridge University I ran a number of Radiation Protection Supervisor courses and gave countless IRMER courses to reluctant clinical staff. I was exceedingly surprised to be awarded the MBE in 2010 for services to healthcare.

Since retiring I have taken up rowing and become a Level 2 rowing coach; I have given two courses on Radiation and Health to the University of the Third Age in Cambridge and am otherwise kept busy with my garden, allotment, grandchildren and church activities. I am still involved on one or two committees for medical physics and radiological protection.