Reflections of a Long (and Illustrious) Medical Physics Career
(Recorded with permission from an interview with Vera in December 2020 )
Vera Page began her medical physics career in the ‘50s at St. Thomas’ Hospital, London. She soon realised that it was to be her professional niche. There was little formal training or specific education. Vera said that “she was just chucked into the deep end.”
St Thomas’ Hospital, London (1956 – 66)
Her work in hospital physics when she started, was mainly in radiotherapy, but included some basic protection and nuclear medicine involvement. Nuclear medicine in those days consisted mostly of thyroid testing and treatment with radioactive Iodine. Later, they acquired a rudimentary ultrasonics machine which was used for finding midline shifts caused by the presence of tumours in the brain. Vera is amazed how far ultrasonics has now progressed.
As the physics work grew and became more specialised, Vera was assigned to Radiotherapy.
St.Thomas’ Hospital had recently installed a cobalt-60 treatment unit to add to their Deep and Superficial X-Ray Therapy machines. There was also a stock of various radium needles and tubes to look after. A pressurised oxygen chamber was later incorporated into some treatments. These did not start until after a second cobalt unit had been installed, as they were very labour intensive and time consuming. The chamber was used for selected patients only, to increase the oxygenation and, optimistically, the sensitivity of certain malignant cells.
Brachytherapy was commonly used for gynaecological intracavitary insertions, based on the ‘Manchester System’. The physicists manually preloaded the radium sources into ‘ovoids’ or a central ‘tandem’, which were then transported to the operating theatre for the surgeon to insert. There was no radiation protection for the surgeon or staff nearby. Sometime later, the Oncology Director invented a semi after-loading system, incorporating a small cobalt-60 source, which would be inserted into a Perspex prepositioned vaginal applicator in theatre. That was considered quite avant-garde!
The Radiotherapy Department had also started to use a special radioactive gold grain ‘gun’, which was used mainly to implant gold grains into the pituitary of a breast cancer patient with metastases. Ablation of the pituitary was carried out to reduce metastases in the same way as an adrenalectomy could. However, this technique had to be abandoned because the gold gave too much radiation to the optic chiasma and thus could blind the patient. The gold was therefore replaced by radioactive Yttrium 90, which emitted beta radiation only and gave far less radiation outside the pituitary. However, the gold grain gun was also used for other treatments, such as for inserting gold grains into encapsulated lung and bladder cancers. The physicist’s job was to receive the gold grains, loaded in a special magazine and sent to the hospital from the Harwell reactor. She would then have to attend the operating theatre and load the sterilised magazine into the gun for the surgeon to use.
Radiotherapy treatment planning in those days was very basic. They used lead wire for contouring and then drawing the patient’s body shape on paper, took AP and Lateral X-Rays for the simulator procedure; and used standard skin-to-source-distance (SSD) isodose curves on tracing paper to calculate the treatment plan. Vera even used her trusty slide rule when planning.
The Manchester calculations for Gynaecological insertions were planned from defined points ‘A’ and ‘B’ measured on an X-ray film, these points indicating the distances drawn either side of the woman’s uterus and cervix mid-line. Vera explained that doing these calculations was very straightforward in theory, but not really so in practice. Insertions were hardly ever ideally positioned by the doctor and, in due course, she started to question the practicalities of this technique. So, she wrote to physicists in all the UK radiotherapy departments (there were not very many in those days) and asked for more details about their actual calculation procedures. The answers she received were quite appalling, as they differed widely. Several physicists didn’t want to reply without an assurance that their replies were not for publishing, but just for her understanding.
This experience made Vera attempt to widen her knowledge. She applied for a one-year sabbatical from St Thomas’ Hospital to visit and learn more from American radiotherapy departments and was delighted to receive approval. The hospital replaced her with a locum physicist imported from New Zealand – a win-win!
Grace- New Haven Hospital, Yale University, USA (1961–62) during one year leave of absence from St Thomas’ Hospital)
With the help of AAPM, Vera found a job at the Grace-New Haven Hospital, Yale university, Connecticut. The position was apparently not as splendid as it sounded. They had not had a radiotherapy physicist before she arrived. Their radiotherapy equipment consisted of an old Van de Graff machine, a 250 KVp X-ray machine, a superficial X-Ray machine plus some radium tubes for gynaecological insertions.
However, Radiotherapy at Yale is considered to be very good these days (she says) and she likes to think that she had set them on the right path.
At the end of her one-year sabbatical, Vera persuaded St.Thomas’ into allowing her an extra month to drive around the United States. She wanted to visit many of the more well-regarded Radiotherapy Departments (and to see around some of the spectacular regions on route). The radiotherapy centres at the MD Anderson Hospital in Texas and the Stanford Medical Centre in California were the most well-known, but there were many other interesting centres on the way where they were always made very welcome. The one that impressed her the most was at the Stanford University Medical Centre, where there was a variety of interesting treatment techniques and many research programmes. Vera was offered a job there, as she had been at all the other centres she had visited. English hospital physicists were highly esteemed.
Vera continued her journey touring through Canada, where she visited the Princess Margaret Hospital in Toronto. She said how lucky she had been to have had the experience of meeting one of the real pioneers of medical physics, Dr. Harold Johns. Vera returned to St. Thomas’ as she had promised. However, several years later, she took up Stanford’s offer to work there, which is where she encountered her first linear accelerator.
Stanford Medical Centre, Stanford University, USA (1966-69)
Dr. Kaplan was the Chair of Radiology. He was a brilliant radiation oncologist and was the inspiration for the construction of one of the first medical linear accelerators, designed by him and built in-cooperation with physicists from Stanford University and Varian Medical Systems. The first linear accelerator at Stanford was a klystron-based 4MV machine suspended from the ceiling. By the time Vera arrived, a 6MV isocentrically mounted treatment unit had also been installed. The isocentric design led to a much more accurate and easier setting up system for patient treatments, allowing the tumour centre to be positioned coincident with the Linac’s centre of rotation. An isocentric dose calculation method had had to be created, to which she was a late contributor and which remains the basis of radiotherapy treatment calculations, even in this computer era.
Soon after starting at Stanford, Vera was asked to develop a calculation method that could give a uniform radiation dose in the treatment of patients with Hodgkin’s Disease, encompassing the whole volume from the top of the neck to the diaphragm – Dr. Kaplin’s ‘Mantle Technique’. As this was well before the days of computer planning and the radiotherapy department was always extremely busy, the calculation system had to be uncomplicated, easy to implement and be within acceptable tolerance and accuracy. The lungs and the heart were routinely shielded by lead bricks. After some basic calculations, Vera created quick lookup calculation tables for a range of patient dimensions. Check measurements were then carried out on an ‘authentic’ phantom (one with bones, lungs, etc) using TLD and film dosimetry which, fortunately, confirmed acceptable accuracy and uniformity. Acceptance of Vera’s publication and the use of her mantle technique calculation system, which was adopted by many countries, attracted an audience of over 1000 for her invited paper at the next RSNA Conference.
Vera was then asked to tackle the technically difficult task of accurately measuring the 4MV electron beam dose on the skin of patients with mycosis fungoides. The treatment involved using electron beams from the older ceiling suspended 4 MV accelerator. Their standard technique entailed treating a patient with large electron beam fields during which the patient was set up in 4 differently rotated positions so as to irradiate all of their skin. Dr. Kaplan wanted to change the number of rotation positions to six in order to improve the skin coverage. Using TLD and film dosimetry, Vera treated the phantom with each of these protocols. She was horrified to discover that the measured skin dose was only half the value previously published!
After reviewing the original paper, Vera found the obvious reason for the dose error. The physicist had measured the electron beam dose with an ionisation chamber, placed in the standard position of patients on this treatment. Unfortunately, the physicist (who had never seen an actual patient being treated) did not realise that the patient would be rotated through various positions, leaving the skin untreated half the time.
This was a serious oversight for the Stanford Medical Centre and a retraction had to be published, so that other centres using their own techniques would not severely under or overdose their patients.
Vera had to quote her favourite mantra:
“All hospital physicists must have contact with patients and all new treatment techniques should be checked using a phantom.”
She also feels that physicists should follow up outcomes of patients treated with any new treatment calculation protocols they have designed.
There was a bonus to this saga as she discovered; the transverse film exposures in the phantom slices made excellent teaching aids!
Vera’s valuable work continued at Stanford for several years while taking every opportunity to travel and attend conferences to learn more (and to see around the country). However, after several years, she decided to return home to England and planned a splendid cruise via Hawaii, the Philippines, Hong Kong and Japan to Australia. She had intended to have a short stay with a cousin in Sydney and tour around Australia before returning to England. As fate would have it, Vera met her future husband within a month of landing in Sydney and naturally never made it back (until much later)
The Prince of Wales Hospital, Sydney (1969 – 71)
The excellent radiotherapy grapevine worked very well for her finding a new job in Sydney. Vera was soon offered a position at the new Prince of Wales Hospital. She was one of the few Sydney physicists with linear accelerator experience, especially as the Varian 6 MeV machine there was like the one she had worked with at Stanford. Therefore, she knew well the need to include beam flatness testing in the routine beam check measurements. She had also learned never to believe unverified meters. The POWH linear accelerator had not been checked for this and, yes, Vera found that the flatness was indeed unsatisfactory, even though the meter showed that it was perfect. That was a problem for the electronic technician, which was fixed without too much drama. But afterwards the checking regime became rather stricter.
Vera settled happily into the very friendly department and stayed almost until the birth of son #1. She was still writing up treatment techniques for an in-house teaching manual when she was in the labour ward!
Sydney Adventist Hospital (1977 – 81)
Vera then left POWH for a fulltime family life. It was not until after son #2 started kindergarten that she agreed to help start a private radiotherapy service at the Sydney Adventist Hospital, where two oncologists had installed a cobalt-60 treatment unit and a superficial X-Ray machine. She said it was really hard being a mother and working unaided as a physicist/planner and being (theoretically) part-time; even in a small radiotherapy department. Having to check outputs and planning patient treatments, in addition to kids’ drop offs and pickups, was difficult. She decided to have a double-double check system in case she made a mistake while in a tizz.
Actual dose calculations were checked by a therapist. However, to avoid a major error, Vera introduced an inverse check method by starting with the final calculation of exposure time and working backwards to the dose the doctor had prescribed. This was intended to guard against double or half-dose errors happening, as had taken place at several hospitals in the past. Unsurprisingly, Vera’s part-time job soon turned into a full-time one as patient numbers increased and she had to take a great deal of work home. Unfortunately, computers were not widely available then.
Royal North Shore Hospital, Sydney (1982 – 97)
Vera’s last job was at the RNSH hospital, where she could return to working on a newer version of the Varian linear accelerator. She was involved in brachytherapy treatment planning with a forward-looking radiation oncologist, Dr. Raj Mallik. He had recently organised for a high-activity radioactive Iridium-192 Gammamed after-loading brachytherapy machine to be installed. This was really exciting for her because it was such an enormous improvement from the old dangerous radium system, still in use in most hospitals. An Ir-192 source, which was attached to a flexible tube of specific length, was irradiated in an overseas nuclear reactor and sent to the hospital. When inserted into the machine, the Ir-192 source could be driven out of the machine and into a specific position in a standard treatment applicator. As Gammamed treatments were remotely controlled, radiation exposure of the staff was minimal. Only the patient was exposed while being treated in the shielded treatment room.
As Ir-192 has a relatively short half-life, the source had to be renewed every few months. As a matter of course, Vera checked the accurate positioning and dose rate for every new source before it was used for patient treatments. The method she used was to attach the cable to the machine and activate the source to drive to its specified treatment position. Then she used a short burst of X-rays onto a film using the Superficial X-Ray machine, which happened to be conveniently installed in the same room. Not long after her arrival, a new source arrived that did not reach the correct position. When Vera reported this to the Gammamed agents, they were really shocked. However, she showed them the evidence on the X-ray film. Coincidently, Vera was an invited speaker at the ‘First Gammamed Users’ meeting held in America, where she reported the source positioning error. It caused a furore, especially as it appeared that no one else had bothered to check the automatic source positioning before using it on patients. Needless to say, Vera was not popular with the Gammamed people! However, many radiation oncologists thanked her afterwards.
After that, Vera said, life continued as in any busy Radiotherapy Department, with more equipment requiring more work and personnel. The RNSH remained a happy and congenial place to work. But sadly, anno domini led to retirement – but not entirely. She worked as a voluntary driver for RNSH radiotherapy patients needing transport and did data management for the department, worked for the NSW Cancer Council and for Cansupport, until medical problems ended her involvement there. Vera is now a proud grandmother of a growing family. However, she still does some voluntary work, goes to U3A lectures and participates in various seniors’ activities.
Vera’s parting remarks were:
“Hospital physics has given me many opportunities in life, work and travel to remember. I was so lucky to have had congenial colleagues and fortunate hospital experiences, leaving me with many happy memories.
Thank you to all my old friends. ”
Vera Page Last, December 2020
For an enlightening interview with Vear Page Last during EPSM 2016, click on this video:
