Nicola Clark – Animal Health Trust

I am a veterinary radiotherapy clinical technologist currently working at the Animal Health Trust (AHT) referral centre in Newmarket. My work involves the preparation and treatment of the cats, dogs and horses that are referred for external beam radiation and high dose rate brachytherapy.

After doing science A-levels at college and various animal-related work experience roles, I undertook a three-year BSc in veterinary sciences at The Royal Veterinary College and graduated with a 2:1. The day after my graduation I started work as a veterinary assistant until I could find myself a veterinary science-based job.

My degree was relatively new at the time and I really struggled to find any jobs related to my degree, so I decided to broaden my job search and looked into the NHS. I typed ‘trainee’ into NHS jobs and one of the vacancies that came up was a two-year pilot training scheme looking for ‘radiotherapy physics clinical technologist trainees.’ The scheme was created to combat the variation in training across radiotherapy centres and was to be funded by the DoH National Cancer Action Team and Modernising Scientific Careers. The vacancy required a science degree of 2:1 or higher and fortunately I was given a place at University College Hospital, London.

Day to day I worked at UCLH alongside the radiotherapy physics team, on rotation through treatment planning, QA and brachytherapy. I was continually assessed via case-based discussions and direct observational procedures and had to complete competencies in each of the set training modules. Despite radiotherapy being so different to anything I had done before, I really enjoyed the challenge and found it very interesting. At the end of my training I gained an IPEM diploma in clinical radiotherapy physics and a place on the register for clinical technologists (RCT). I really enjoyed my job and ended up staying at UCLH as a technologist for a further two years, building on all of the competencies I had learned. After four years of work, I was competent to plan conformal, external beam breast, prostate, gynae, oesophagus, limb, SCF, brain and TBI plans, plus gynae and prostate brachytherapy plans. I was also able to do linac, CT, brachy and Gulmay QA.

However, during my time at UCLH, I became curious to know if radiotherapy could ever be considered for animals. I learnt that there were six veterinary centres in the UK with a linac for animal use. I arranged to do a week of work experience at Cambridge University vet school and it was amazing to see animals benefitting from this technology too. A couple of years later, I happened to see an advert for a veterinary radiographer position at AHT while I was reading a copy of RAD Magazine. I told them of my background, making it clear that I wasn’t a radiographer but they encouraged me to apply anyway and ended up offering me the job. I now get to apply all of the skills and qualifications I’ve gained throughout my career in the same job and have been doing so for four years now.

At AHT I treat cats and dogs with conformably planned, external beam radiation using a Varian linear accelerator equipped with MLC and an MV imaging panel, ARIA and Eclipse. The linac is run up every day and routine QA performed, just as you would expect in a human hospital. I also CT scan our radiotherapy patients for planning. We most often treat brain tumours, but also treat anal sac carcinomas, limb sarcomas, mast cell tumours, nasal adenocarcinomas, oral melanomas and soft tissue sarcomas of the limbs and head and neck. As such, very specific radiotherapy immobilisation devices such as head shells and vacuum bags need to be created. Patients are generally placed ‘prone’ onto a vacuum bag, with their forelimbs placed down by their sides. Patient necks are positioned on top of a human head rest (and actually fit quite well) and a shell is moulded over them. If necessary, patients may also have a mouth bite made for them. We have found that this set-up gives very good immobilisation of the head and neck.

Definitive treatments are commonly 20 fractions Monday to Friday for four weeks and palliatives often four fractions once weekly. Patients are given a general anaesthetic to ensure compliance and stillness and are set up in their immobilisation devices aligned to the in-room lasers. Patients are imaged using the MV imager and image matched. We have a 2mm tolerance in the lateral, longitudinal and vertical positions. We then treat with 6MV photons. Some patients, such as limb patients, do not require a conformally planned treatment and instead have a manual plan. These are planned ‘on set’, a manual calculation performed and then treated with either 6MV photons or electrons. Of course, just like human patients, we do see side effects to treatments. Erythema and epithelial desquamation is not uncommon for limb patients and requires pain killers, topical medication and a buster collar.

The trust also uses high dose rate brachytherapy to treat ocular sarcoids in horses. This is something that is not yet done in any other veterinary centre in the UK and in only a handful of places worldwide. Treatment is performed under standing-sedation with the horse stood in stocks. Brachytherapy catheters are placed in and around the sarcoid and then imaged orthogonally using a C-arm and marker wires. These images are used to create a brachytherapy plan on Eclipse and then, after final checks, the patient is treated with AHT’s GammaMed remote afterloader Iridium-192). The majority of horses cope really well with this procedure and the results we have seen so far have been very encouraging.

In the future, I would love to see more veterinary centres setting up a radiotherapy service so that more of our pets can benefit from this incredible technology.

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