Sharp Blue: Radiotherapy (redux)


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Life and death are slow in Oncology. My dominant memory of my dad’s treatment will be the many hours of waiting. A casual observer could think that the Bristol Oncology and Haematology Centre is a machine for shuffling patients and their families from one waiting area to another. Like war, the interludes of action are small islands of activity in a vast sea of boredom. Over the last weeks, I’ve waited in the Oncology reception, the Radiology reception, outside the radiotherapy simulation room, outside the actual radiotherapy room, in examination rooms, in X-ray, CT and MRI waiting rooms, in the reception of the dental hospital and probably more places I’ve forgotten. All around there are other people waiting, some reading, some chatting quietly, some staring into space. I see now why they’re called patients. Many of them have to be there every day for months. Occasionally, a young, bright nurses arrives to take someone off to be scanned or prodded or transfixed by beams of high-energy photons. Mostly, though, we wait.

Today we had longer to wait than usual. My dad was having the cancerous area in his leg treated, and this entailed having a “simulation session” and then a few hours later having the actual x-ray dose. The basic idea behind radiotherapy is that high-energy photons can break up molecules to produce free radicals that then damage cellular machinery. Cells contain repair mechanisms that correct for free radical damage, but this works less effectively in cancer cells than in normal cells. This means that a given dose of x-rays will cause more damage to the tumour than the surrounding tissue. To maximise the dosage to the tumour while limiting damage to the rest of the body, it’s usual to fire the beam into the cancerous region from several different directions. The source of the x-rays is a linear accelerator that fires 8MeV (if I remember correctly) electrons into a target. The patient lies on a bed and the linac itself, a substantial piece of machinery, can rotate around the bed’s axis to direct the beam from multiple angles. Today, they attacked the leg tumour from two orientations. Next week, when they irradiate the brain tumour they’ll traverse several arcs around my dad’s head.

Needless to say, you don’t want to point the linac at the wrong place, so before going under the hot beam you have to have a session in the simulator. This looks just like the actual treatment machine but it only uses low-energy x-rays. These are used to take x-rays of the tumour from various directions to work out exactly where to direct the beams. The radiotherapist uses the results from these x-rays to draw guide marks onto the patient’s body. The treatment room then has a gadget for projecting a grid of laser light that can be used to precisely align the patient in the machine. Another technician checks the programme of beam energies and orientations. When the patient is aligned and the programme checked, everyone else has to evacuate the room and hide behind thick concrete shields. The warning lights click from green to red and the linac is powered up. It’s almost an anticlimax. There’s not even a hum of power, let alone a dimming of lights. A few minutes later and the dose has been administered and the patient can get dressed and go home.

Last time round, that’s when things got unpleasant. The tumour in my dad’s back was positioned such that the beam would pass through his stomach, and within an hour or two of the end of each treatment he’d start to feel very nauseous for a few hours. The aftermath of the last treatment of that course was especially unpleasant because he hadn’t been able to take his anti-emetics at the right time because of a delayed taxi. I wasn’t quite sure what to expect today, but in the end he had no immediate side-effects. Instead, he, my mum and I walked a little way into Broadmead, Bristol’s main central shopping district, and had lunch in a cafe, and then came home by bus. It’s a few hours later now and he’s still feeling fine. With a little luck, that’s the last we’ll hear of that particular tumour…

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