Preparation for Radiotherapy to the Pelvis

Patient Experience

  • Reference Number: HEY-741/2020
  • Departments: Radiotherapy
  • Last Updated: 31 March 2020


This leaflet has been produced to provide specific information for those patients with cancer within the pelvic area who have been referred for Computed Tomography (CT) planning prior to their radiotherapy treatment. It provides details of preparation required before you attend your CT and treatment appointments. If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

Why do I need to have an empty rectum and a full bladder?

Your course of radiotherapy will be planned on an individual basis using special CT Planning scans.

The organs within your pelvis, for example the uterus (female) or prostate (male) will naturally change position slightly, depending on how full your rectum W bladder are. Therefore, in order to give radiotherapy directly to the identified area, it is important that it is in the same position for all your treatments as it was for your CT planning scan. The most effective way to ensure this, is for you to have an empty rectum (bowels) and a comfortably full bladder for each appointment.  This will be checked with daily imaging before your radiotherapy, to ensure positioning of the treatment is accurate. You may have more than one scan if your bladder and bowel positions are not suitable. An empty rectum does not mean you cannot eat regularly.  Please continue to eat regularly as you normally do.                   

How do I prepare for the CT planning scan and daily radiotherapy treatment?

Guidance to keep your bladder full

Ideally you should feel comfortable whilst keeping the bladder full and not straining yourself to hold urine. Hydration is a very important factor. Please try to drink 2 litres of water a day.  If you are not well hydrated before you drink your water for the treatment, hardly any water will pass to the bladder. As a guide we recommend you drink 500ml of water in the morning before your appointment.

We suggest if you are travelling a long distance to your appointment, you should empty your bladder just before leaving home. To enable your bladder to fill sufficiently, please allow extra time before your appointment time where possible.

On arrival in the department, wait for further instructions from the radiographers who will be conducting your CT planning scan.  These instructions will need to be repeated everyday whilst attending for your treatment.

Please inform the radiographers before the CT planning scan or daily radiotherapy treatment if you have or have not been able to do this.

What if I cannot hold water for more than one hour?

If you have difficulty holding urine, we may need to amend the type of preparation for your treatment. If you feel this applies to you, please tell the radiographer at your CT planning appointment before the procedure takes place.

Guidance to keep your rectum (bowel or back passage) empty

There are various ways of keeping your rectum empty.  Your consultant will suggest one of these methods, even if your bowels are opened regularly:

Method 1: Taking any laxative (e.g. Movicol)

Start taking the Movicol 3 days before your CT planning scan appointment and then again 3 – 5 days prior to starting your daily radiotherapy treatment. Then continue to take the laxative during the course of your daily radiotherapy, or until advised otherwise by a medical professional.   It is usual to take the laxative at night, before going to bed.

Method 2: Glycerin suppositories

Use a Glycerin suppository (inserted via the back passage) at least one hour before you leave home on the day of your CT planning scan. Then continue taking every day whilst having your daily radiotherapy sessions. Again, use at least one hour before you leave home, to allow it to work before starting a journey to the Castle Hill Hospital.

Suppositories should be taken at least 1 hour before you leave your home because it will take 15-45 minutes to work.  If you have a long distance to travel, it is worth having a practice using them 1-2 days before your CT planning scan so you will know how long they take to work. We suggest that you moisten the suppository under running water before you insert it into your back passage following the instruction leaflet.

What if the suppositories do not work or are uncomfortable to use?

Laxatives or suppositories must be used before your CT planning appointment and also before each radiotherapy session. If you find that you are uncomfortable using suppositories or they are not working, please discuss this with your treatment radiographer or speak to the radiotherapy nurse within the radiotherapy department, as alternative laxatives may be prescribed.

Method 3: Fybogel

Start taking fybogel 5 days before your CT planning scan. On the day of your CT planning scan use the glycerin suppository at least one hour before you leave home. Then keep taking fybogel the night before each of your daily radiotherapy session.

Method 4: Enema

Enemas can be given for patients struggling to empty their bowels. A phosphate enema is a very fast acting enema and is given in the department. Micro enemas are a slower acting enema and are usually given 1 hour before CT and treatment and takes 20 minutes to work.

What if I start having diarrhoea?

One of the side effects of radiotherapy is diarrhoea or loose stools. Generally this symptom starts around the second or third week of radiotherapy treatment. If you have loose stools, please discuss it with treatment staff or radiotherapy nursing team at your next appointment, you may also stop your bowel preparation.

When do I stop using suppositories and laxatives?

If you start getting diarrhoea more than 3 times a day, uncomfortable back passage soreness, abdominal cramps or abdominal pain then stop using glycerin suppositories and laxative and inform the radiographer or nurse.

What will happen at my CT planning scan appointment?

Full information regarding your scan can be found in the ‘Introduction to Radiotherapy CT Planning’ leaflet which can be given to you by a member of staff.

What will happen at my treatment appointments?

You will be required to repeat the drinking and bowel preparations process that you are asked to do at your CT planning scan. A radiographer will run through any individual process on your first day of treatment.

Dietary advice whilst attending for CT planning and radiotherapy treatment

It is advisable to reduce a high fibre diet e.g. fruits and vegetables with the skins left on and any type of food that causes excessive gas formation for your CT planning scan and during your radiotherapy treatment. We advise reducing these types of foods 2 – 3 days before your CT planning appointment and again 2 – 3 days before commencing your daily radiotherapy treatment and during the full course of your daily radiotherapy.

Please DO NOT change dramatically what you eat as your body is used to your routine. If a large change in eating habit is required to reduce the amount of matter/gas in the bowel we will advise you at your CT appointment. Please do not stop eating or fast before your appointment as this can lead to problems such as excess gas in your bowel.

Gas (wind) in the bowel

As part of the preparation for your radiotherapy we need you to try to limit the amount of gas in your bowel.  Air in the digestive tract is perfectly normal – everyone has it.  Gas enters the bowel either by swallowing or by the breakdown of certain foodstuffs. Some foods that cause gas in some people will not in others.

We do not want you to make drastic changes to your diet or lifestyle but the following advice may be helpful before and during your radiotherapy.  Reduce the amount of air you swallow by:

  • avoiding chewing gum
  • avoiding fizzy (carbonated) drinks
  • avoiding eating and drinking too fast

Reduce the amount of air caused by food breakdown by limiting the amount you eat of the following products although it will not harm you to eat them in moderate amounts:

  • nuts/seeds
  • beans
  • broccoli
  • onions
  • mushrooms
  • cabbage
  • cauliflower
  • raisins
  • lentils and pulses
  • prunes
  • brussel sprouts
  • fruit juices containing ‘bits’
  • ‘sugar free’ products containing sorbitol or mannitol (this is displayed on packaging)

Try to keep portions of fruit to two per day.

Remember please do not change your diet dramatically or fast prior to your CT as your body is used to your natural eating habits.

Should you require information on the appropriate types of food we are indicating please ask a member of staff for guidance.  We also suggest that you avoid coffee, tea and alcohol 2 – 3 hours before going to bed as this may help in reducing excessive night time frequency of passing urine. You may still drink water as this does not contain caffeine..

General advice and support services

Most of your questions should have been answered by this leaflet. If you have any further questions please ask any member of the healthcare team caring for you.

Female patients aged between 12 and 55 years of age will be asked if they are or might be pregnant. If at any point during your radiotherapy treatment you suspect that you may possibly be pregnant, you must inform your treatment team immediately.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Radiotherapy Information and Support Team (01482) 461206 or email:

Please read the information leaflet.  Share the information it contains with your partner and family (if you wish) so that they can be of help and support.  There may be information they need to know, especially if they are taking care of you following this examination.

Radiographers – These highly trained specialists are involved in your treatment from CT and throughout you radiotherapy. You will see where possible, the same team of radiographers each day you attend for your treatment.  They are there to help you.  If you have any problems or worries, please speak to them for any help and advice.  You may also be referred to another member of the Oncology Team as necessary.

Radiotherapy Nursing Team – Consisting of registered nurses and clinical support workers and are based within the Radiotherapy Department.  They actively support and advise patients receiving radiotherapy treatment and are able to make appropriate referrals and offer advice to patients and their families / carers.

Health Centre – The primary aim of our Health Centre is to help patients and their families to have the best possible health and quality of life during and after treatment.  The Health Centre is open to all oncology patients and their families in offering an informal atmosphere to those who wish to “drop in” to the centre.  Within the Health Centre, there are specially trained staff who are able to advise on different aspects of coping with cancer.

The centre is located in the Main Reception of the Queen’s Centre for Oncology and Haematology at Castle Hill Hospital.  The opening times are Monday – Friday 9:00am to 5:00pm

Useful Contacts

Listed below are the contact details of useful organisations that provide information about cancer, including radiotherapy treatments:

Macmillan Cancer Support

Provide information from specialist nurses on all aspects of cancer and its treatment and on the practical and emotional aspects of living with cancer.  You can drop into the Macmillan Cancer Information Centre within the Queen’s Centre or contact them on: (01482) 461154 (Monday – Friday 9:00am to 5:00pm)

Alternatively free phone the national help line: 0808 808 0000 (Monday – Friday 9:00am to 8:00pm)


Write to: Macmillan Cancer Support, 89 Albert Embankment, London, SE1 7UQ

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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