Radioisotope (molecular radiotherapy) treatment
A treatment that uses a radioactive medicine, given as a drink, capsule or injection, that travels through the body and is taken up by cancer cells so the radiation is delivered from the inside. It comes with radiation-safety precautions for a period afterwards.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- It uses a radioactive medicine, given as a drink, capsule or injection, that is taken up by cancer cells so radiation is delivered from inside the body.
- Different radioisotopes target different cancers; many are used to control advanced cancer or its symptoms rather than to cure it.
- There are radiation-safety rules afterwards, including limiting close contact with young children and pregnant people, and sometimes a stay in a shielded room.
- The treatment keeps acting for weeks to months and the response is judged at planned follow-up; your team should be clear about the realistic aim.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Can reach cancer cells around the body, including disease that has spread, by targeting them directly
You are pregnant or breastfeeding, or there is any chance you could be pregnant.
Follow the contact and hygiene rules you were given. You may feel tired, mildly nauseated, or notice a temporary flare of symptoms such as bone pain with...
Clear written radiation-safety instructions with exact timescales for each restriction.
Follow the contact and hygiene rules you were given. You may feel tired, mildly nauseated, or notice a temporary...
Limit close contact with young children and pregnant people, and follow sleeping and hygiene advice, for exactly...
If you are having a course, you return for further doses weeks apart. Blood tests and sometimes scans check your...
The treatment keeps acting on the cancer. Follow-up scans or tests assess the response, and your plan is reviewed.
What is radioisotope (molecular radiotherapy) treatment?
Radioisotope treatment, also called molecular radiotherapy or radionuclide therapy, uses a radioactive medicine to treat cancer from the inside. The medicine is given as a drink, a capsule or an injection, then travels through the body and is taken up by cancer cells, where the radiation acts over a very short distance to damage them while sparing more of the healthy tissue around.
Different radioisotopes target different cancers. Examples include Lutetium-177 PSMA therapy and radium-223 (Xofigo) for some advanced prostate cancers, Lutetium-177 dotatate (a type of PRRT, peptide receptor radionuclide therapy) for some neuroendocrine tumours, and 131I-MIBG for certain neuroendocrine tumours. (Radioactive iodine is also used for thyroid cancer and, at lower doses, for an overactive thyroid, which is covered separately.)
Because you take radioactivity into your body, there are radiation-safety rules afterwards. You may give off a low level of radiation for a while, so you are given clear advice about contact with other people — especially young children and anyone who is or might be pregnant — and about hygiene at home. Some treatments need a short stay in a shielded hospital room.
Many of these treatments are given to control advanced cancer and its symptoms, sometimes over several courses, rather than to cure it. Your team should be honest about whether the aim is to cure, to control the cancer, or to relieve symptoms, and about what the treatment can and cannot do.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Molecular radiotherapy compared with external radiotherapy
| Feature | Molecular radiotherapy | External radiotherapy |
|---|---|---|
| How it is given | A radioactive medicine taken into the body | A beam from a machine outside the body |
| Where it acts | Wherever the cancer cells take it up, including spread | Only the area the beam is aimed at |
| Radiation safety | You give off radiation for a while, with rules to follow | You are not radioactive afterwards |
| Common aim | Often to control advanced cancer or symptoms | Cure or symptom control depending on the cancer |
These are different tools. Molecular radiotherapy can reach cancer that has spread around the body, but brings radiation-safety rules. The right choice depends on your cancer.
Preparing for your treatment
- Talk through why this treatment is being recommended, whether the aim is to cure, to control the cancer or to relieve symptoms, and what the alternatives are.
- Tell the team if there is any chance you are pregnant; these treatments must not be given in pregnancy, and a test is usually done first.
- Ask whether you will be an outpatient or need a stay in a shielded room, so you can plan time off and support.
- Discuss the radiation-safety rules in advance: who you live with, whether you care for young children, work and travel.
- Ask about any preparation, such as medicines to protect the kidneys for some treatments, or scans to check the cancer takes up the isotope.
- Mention all your medicines and any kidney, bone marrow or other conditions, and ask about effects on fertility if relevant.
- Bring a list of questions and your recent scans and blood tests.
What happens
You attend a nuclear medicine or oncology department. After checks to confirm it is safe to go ahead, you are given the radioactive medicine — swallowed as a capsule or drink, or given as an injection. The appointment to receive the dose is usually short.
Some treatments are given as an outpatient, so you go home the same day with written radiation-safety instructions. Others, especially those that give off more radiation such as 131I-MIBG, need a stay in a special shielded room with limited visitors until the radiation level falls enough for you to go home safely.
You are given clear rules about contact with other people — particularly young children and anyone who is or might be pregnant — sleeping arrangements, and hygiene at home, and told exactly how long each rule applies, as this depends on the isotope and dose.
Many of these treatments are given as a course of several doses, weeks apart. Between and after treatments, scans and blood tests check how the cancer is responding and look after your kidneys and blood counts.
Is this treatment right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- You are pregnant or breastfeeding, or there is any chance you could be pregnant.
- The cancer does not take up the radioisotope, so the treatment would not reach it.
- Your kidney function or blood counts are too low to have the treatment safely.
- You cannot follow the radiation-safety rules, for example you are the sole carer of very young children with no alternative.
- Another treatment is expected to work better for your situation.
Delay or rearrange if…
- There is any possibility of pregnancy until this has been excluded.
- You have an active infection or your blood counts are too low and need to recover first.
- Your kidney function needs checking or improving before treatment.
- You cannot yet arrange childcare or living arrangements to follow the safety rules.
- Important staging results or an MDT decision are still awaited.
Alternatives to discuss
- Other systemic treatments such as chemotherapy, hormone therapy, targeted therapy or immunotherapy.
- External radiotherapy, including palliative radiotherapy for symptom control.
- Surgery, where the cancer is operable and that is the better option.
- Best supportive or palliative care where comfort and quality of life are the priority.
- A clinical trial, if one is suitable and available.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Can reach cancer cells around the body, including disease that has spread, by targeting them directly
- Delivers radiation over a very short distance, sparing more nearby healthy tissue
- Can shrink tumours, slow the cancer down or relieve symptoms such as bone pain in suitable cases
- Is usually given without an operation or general anaesthetic
- Can be repeated as a course where appropriate
Risks & complications
- Tiredness during and after treatment
- Needing to follow radiation-safety restrictions that disrupt normal family, work and social life for a period
- Mild nausea or a temporary change in taste with some treatments
- Temporary worsening of symptoms (such as a short-lived flare of bone pain) with some treatments
- A drop in blood counts, raising the risk of infection, bleeding or anaemia
- Effects on the kidneys with some treatments (which is why protective measures may be used)
- Dry mouth or dry eyes with some treatments
- The cancer not responding as hoped, so the plan needs to change
- Serious or lasting effects on the bone marrow or kidneys
- Rarely, a second blood cancer or bone marrow problem years later with some treatments
- Severe allergic or other reactions to the medicine, which the team is prepared to treat
The most important things to understand are the radiation-safety rules and how long they last, the effects on your blood counts and kidneys (which need monitoring), and whether the aim is to cure, control or relieve symptoms. These treatments must be avoided in pregnancy and breastfeeding. Ask your team which specific effects apply to your treatment, how they will monitor you, and exactly what the safety rules mean for your home life.
Published figures to discuss
Outcomes and side effects depend on the specific radioisotope, the cancer type and how much it has spread, your kidney and bone marrow function, and whether treatment is given as a course, so a single set of figures would be misleading. Most of these treatments aim to control advanced cancer or relieve symptoms rather than cure it. Effects on the blood counts and kidneys, and radiation-safety needs, are the main practical issues. Because robust figures that apply to every person do not exist across these different treatments, we describe the pattern rather than invent precise percentages, and your team can give numbers specific to your treatment.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Bone-marrow suppression | Uncommon to common depending on isotope, prior treatment and marrow reserve | Blood counts are monitored because anaemia, infection risk or bleeding can occur. | UCLH NHS Foundation Trust — Lutetium-177 PSMA radionuclide therapyuclh.nhs.ukSource-linked context |
| Kidney or salivary-gland exposure with some molecular radiotherapy | Treatment-specific | Hydration, amino-acid protection or salivary advice may be used depending on the isotope. | Guide sourcesClinical context |
| Radiation-safety restrictions after treatment | Expected and temporary | Advice about distance from others, toilets, laundry, children and pregnancy contacts depends on the isotope and dose. | Guide sourcesClinical context |
| Cancer response being partial or temporary | Common in advanced disease settings | Many radioisotope treatments aim to control disease and symptoms, not guarantee cure. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is usually no physical recovery in the surgical sense. Afterwards, the main things are following the radiation-safety rules, managing any side effects, and waiting — often over a course of treatments — for follow-up scans to judge how the cancer is responding.
- Feeling tired for a while after each treatment
- Needing to keep your distance from young children and pregnant people for a set period
- Mild nausea or a temporary change in taste with some treatments
- A short-lived flare of symptoms, such as bone pain, soon after some treatments
- No immediate change in the cancer, because the treatment keeps acting over weeks to months
Aftercare
- Follow your written radiation-safety instructions on contact with others, sleeping arrangements, travel and hygiene for exactly as long as advised.
- Avoid close, prolonged contact with young children and anyone who is or might be pregnant for the period your team specifies.
- Drink plenty of fluids and follow any toilet-hygiene advice in the first days, as instructed.
- Take any medicines, including kidney-protective or anti-sickness medicines, exactly as directed.
- Attend all blood tests and scans, even when you feel well, so your blood counts, kidneys and response are monitored.
- Keep your treatment record, as you may set off radiation detectors at airports or ports for a time.
- Report signs of infection, unusual bleeding or bruising, or worsening symptoms promptly.
- Written radiation-safety instructions understood and kept
- A plan for childcare if you look after young children
- Sleeping and contact arrangements at home sorted for the restriction period
- Follow-up blood tests and scans booked
- Prescribed medicines (including kidney-protective ones, if relevant) collected
- Treatment record card kept for travel
- Clear contact number for the department saved
⚠ Get urgent help if…
- A high temperature, shivering or feeling very unwell, which could mean a serious infection when blood counts are low
- Unusual bruising, bleeding, or a rash with feeling unwell
- Severe or worsening pain not controlled by the painkillers you were given
- Passing much less urine, or swelling, which could point to a kidney problem
- Severe nausea, vomiting or inability to keep fluids down
- Any concern that you might be pregnant after treatment
- Any symptom your team has told you to report straight away
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good result is the cancer responding — shrinking, slowing down, or symptoms easing — but these treatments work gradually and often over a course, so the response is judged at planned follow-up scans or tests, not on the day. Your team will explain what they are looking for.
Many radioisotope treatments are given to control advanced cancer or relieve symptoms rather than to cure it, and none can guarantee a cure or that a cancer will not progress. Your oncologist should be honest about whether the aim is cure, control or symptom relief, and about how long any benefit might last.
How long the benefit lasts depends on the cancer type, how it responds and the rest of your treatment. Some people get useful control or symptom relief for a period, after which the cancer may progress and other treatments are considered. Because effects on the blood and kidneys can appear later, and the cancer needs ongoing monitoring, long-term follow-up is important.
Related tests, treatments or support
Radioisotope treatments are often used alongside other cancer treatments, such as hormone therapy for prostate cancer or other treatments for neuroendocrine tumours, as part of a plan agreed by a multidisciplinary team. Some, such as radioactive iodine for thyroid cancer, follow surgery. The plan depends on your cancer type and what has been tried before. This guide covers radioisotope treatments for cancer; lower-dose radioactive iodine for an overactive thyroid is covered separately.
Follow-up & long-term care
After treatment you stay under your oncology and nuclear medicine team's care. Follow-up includes blood tests and scans to monitor your blood counts, kidneys and the cancer's response, and to plan any further doses. You should be told who to contact between appointments, and private care should be coordinated with your NHS team and GP.
- Attending follow-up blood tests and scans to monitor blood counts, kidneys and response
- Following radiation-safety advice for each treatment in a course
- Reporting infection, bleeding, kidney or worsening cancer symptoms promptly
- Keeping a treatment record for travel and future care
Repeat, follow-on and what comes next
- These treatments are often given as a course of several doses, with the plan reviewed using scans and blood tests.
- Treatment may be paused, reduced or stopped if blood counts or kidney function are affected.
- Further or different treatment may be needed if the cancer does not respond or later progresses.
- Late effects on the blood or kidneys may need their own management.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- Clear written radiation-safety instructions with exact timescales for each restriction.
- Scheduled blood tests and scans to monitor blood counts, kidneys and the cancer's response.
- A named contact and clear emergency advice for infection, bleeding or kidney problems.
- Specific advice on pregnancy avoidance and a treatment record for travel.
- Coordination between any private team, your NHS oncology and nuclear medicine teams, and your GP.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The oncologist's and nuclear medicine team's fees for planning and giving treatment
- The specific radioisotope used and the number of treatments in a course
- Whether treatment can be given as an outpatient or needs a stay in a shielded room
- Scans to check the cancer takes up the isotope, and monitoring scans afterwards
- Blood tests and any kidney-protective or supportive medicines
- Follow-up appointments and management of any side effects
- The specialist and facility fees for the full course of treatment
- Whether a shielded-room stay is included and for how long
- Scans to assess uptake and to monitor response
- Blood tests and supportive or kidney-protective medicines
- Follow-up appointments and who provides them
- What happens, and what it costs, if further treatment is needed or a complication occurs
On the NHS? Several radioisotope (molecular radiotherapy) treatments are available on the NHS for approved indications when clinically appropriate; private care is mainly used for speed or choice and should be coordinated with your NHS team.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not being clear whether the aim is cure, control or symptom relief.
- Vague or missing radiation-safety instructions, especially about young children and pregnancy.
- Not being told about effects on the blood counts and kidneys and the need for monitoring.
- No clear advice on avoiding pregnancy or fathering a child afterwards.
- No plan or named contact for managing side effects or a cancer that progresses.
Marketing red flags
- Any promise or strong implication of a guaranteed cure, especially for advanced cancer.
- Offering an unproven radioisotope treatment, or one outside approved indications, without clear evidence.
- Playing down the radiation-safety rules or the need for blood and kidney monitoring.
- Quoting impressive response figures without the source, cancer type or follow-up length.
- Overseas or private clinics promising results that are not supported by evidence.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Is the aim of this treatment to cure the cancer, to control it, or to relieve symptoms?
- Will I be an outpatient or need a stay in a shielded room, and how many treatments will I have?
- Exactly what radiation-safety rules apply, and for how long, in my case?
- How will you monitor and protect my blood counts and kidneys?
- How and when will you check whether the cancer is responding?
- Could this affect my fertility, and how long should I avoid pregnancy or fathering a child?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my treatment, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this treatment not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Will I be radioactive to other people?
Is this treatment a cure?
Can I have it if I am pregnant or breastfeeding?
Is it available on the NHS?
What side effects should I expect?
Why might I need to stay in hospital?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: Cancer Research UK — Radioisotope therapy UCLH NHS Foundation Trust — Lutetium-177 PSMA radionuclide therapy Macmillan Cancer Support — Radiotherapy types of treatment Royal College of Radiologists — Clinical oncology NHS — Radiotherapy
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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