Radiation and Diabetes Devices — Insulin Pumps and CGM Sensors

Diabetes and cancer are increasingly treated in the same person at the same time. The number of patients arriving for radiotherapy already wearing a pump or a sensor grows every year — and yet most radiotherapy information sheets say nothing at all about these devices. Patients end up piecing the answer together from a pump manual and a rushed conversation in a corridor. This page puts it in one place.

The rule itself is simple, and it comes from the device makers rather than from your cancer team. The instructions for use supplied with insulin pumps and continuous glucose monitoring systems advise removing the device from the body before radiotherapy, and before X-ray, CT and MRI, and keeping it outside the room. The reason is exposure to the beam. It has nothing to do with having diabetes, and nothing to do with your safety around other people.

Your radiotherapy is delivered at an NABH-accredited partner centre; CION Cancer Clinics coordinates your treatment plan, your oncology team and your care throughout — including the handover to your diabetes team about pump timing and sugar checks on treatment days.

The rest of this page answers the three questions in the order patients ask them: must it be removed, can it be damaged, and how are sugars monitored while it is off.

What removal actually involves:

• The pump is disconnected, not surrendered. You unclip at the infusion set, leave the pump with a relative or in the changing area outside the room, and clip it back on when you come out. The cannula normally stays in place.
• A sensor in the treatment field comes off. A sensor or transmitter sitting on the skin being treated is removed for two reasons: the beam reaches it, and anything resting on the skin surface changes the dose the skin itself receives.
• A sensor away from the field is still discussed. Even when it sits well clear of the treatment area, your team follows the manufacturer instruction and agrees with you whether it comes off for every session or only for the planning scan.
• The planning scan counts too. The CT simulation that maps your treatment is an X-ray scan, so devices come off for it as well. A sensor left in place can also create artefact on the very images used to shape your beams.
• Nothing is removed without a plan for it. Removal is agreed in advance with your diabetes team, so you know what to check, when to reconnect, and what to do on the days a sensor has to be re-sited.

If a session is delayed and you are off the pump for longer than expected, say so rather than waiting. A short gap is planned for; a long one needs your diabetes team to cover it.

These devices were designed for daily life, not for a treatment room. Manufacturers do not test them against therapeutic radiation doses, so their guidance is the cautious one: assume the beam can affect the electronics, and keep the device away from it. That is a statement about what has been tested, not a warning that damage is likely.

If a device is left on by mistake during a session, tell the radiographer straight away rather than at the end of the week. The device is then checked and its settings confirmed instead of being assumed correct, and your diabetes team decides whether it needs replacing. A device that has been exposed does not become radioactive, and it is not unsafe to have near your family.

Damage here is a question about equipment, not about your body. It is inconvenient and solvable — it is not a reason to postpone treatment your oncology team has recommended.

This fear attaches itself to devices in a particular way. Patients who have been told their pump must be kept out of the room often conclude that the machine puts something into it — and then start keeping their distance at home as well. It does not, and there is no reason to. The pump is kept outside the room to protect the pump.

The same reassurance extends to whoever comes with you. Relatives waiting for you are not exposed to anything, and Is It Safe for Caretakers to Sit in the Radiation Waiting Area? sets out why. If pregnancy or feeding a baby is part of your household picture, those are genuinely separate questions with careful answers — see Radiation Therapy During Pregnancy: Is It Ever Possible? and Can I Breastfeed During or After Radiation Therapy?

The only treatments where genuine household precautions apply are permanent seed implants and radioiodine therapy, and those precautions come from the radioactive material itself — never from a diabetes device.

• If you also have hardware inside your body, Metal Implants, Plates and Joint Replacements During Radiation explains what is planned around and what is simply left alone.
• If relatives bring you in daily, Is It Safe for Caretakers to Sit in the Radiation Waiting Area? answers the question they are often too polite to ask.
• If you are feeding a baby, Can I Breastfeed During or After Radiation Therapy? separates what depends on the treatment site from what does not.
• If you are pregnant, or think you might be, read Radiation Therapy During Pregnancy: Is It Ever Possible? before anything else.
• For the full picture of how radiotherapy is planned, delivered and coordinated with NABH-accredited partner centres, see Radiation Therapy at CION Cancer Clinics.

Still unsure how your pump or sensor fits around treatment? Book a free consultation or call us on 1800 202 8726 and a radiation oncologist will talk it through.