Pre treatment

A CT (computed tomography) scan enables your health care team to gather information in order to plan your radiotherapy treatment.  The pictures taken (x-rays) are displayed on a monitor and examined by your oncologist to see exactly where the cancer is and what healthy tissues or organs are nearby.

What happens during the CT planning scan?

You will be taken to the CT scanning room by one of a small team of radiographers who will carry out the scan. The room houses the CT scanning machine, (a doughnut shaped structure about two feet thick) which you pass through on a couch and a curtained area to give you privacy while getting dressed/undressed if this is necessary. (Only the area of the body being treated needs to be uncovered, the rest of your clothing need not be removed). You may be asked to put on a modesty gown.

Working with the radiographers you will be placed in a suitable position; you will be in this position for your treatment. So, it is important you are comfortable enough to hold this position for 10 to 15 minutes daily. The radiographers will draw some reference marks on your skin with a pen and place markers over them so they will show up on the scan. The couch will be moved slowly to position you within the doughnut. There is no pain or sensation while we carry out this scan.  The radiographers need to leave the room when they do the scan. While the radiographers are out of the room, they are watching you all the time through a window and will be able to talk to you via an intercom.

Please keep as still as possible during this time.  This scan is very quick and quiet unlike some previous scans you may have had.

Is any preparation needed before my CT planning appointment?

This will depend on the area of the body we are scanning.

If any preparation is needed, you will receive an information pack detailing this.

Please read this carefully and follow the instructions.

Will I need to have an injection?

For the examination of certain areas of the body, your doctor may have requested an injection of a contrast medium to allow us to get as much information about your condition as possible. This involves inserting a cannula into a vein in your arm.  The needle may hurt briefly while it goes through the skin, but after that, you should not feel any pain.

As the contrast is injected, you may feel a warm sensation passing around your body which should only last a couple of minutes.

You will be able to eat and drink before attending for your CT planning scan unless advised otherwise on your appointment letter.

How long will the appointment take?

Although the CT scan itself takes only a few minutes, the appointment can take 30-60 minutes. If there is any additional preparation needed prior to your scan, this may take more time.

Will I have to hold my breath while I am being x rayed?

Not usually, although we will ask you to keep as still and relaxed as possible during the scan to ensure that your treatment is planned accurately.

There are some scans which will require you to hold your breath. Your doctor will have discussed this with you if applicable.

Are there any risks?

CT scanning does involve x-rays; therefore patients who are, or might be pregnant must inform a member of staff in advance.  There is a slight risk of an allergic reaction to the injection, however the staff in the radiotherapy department are trained to deal with any complications and the risk involved is very small.  If you have had a reaction to an injection for a previous CT scan, you should tell the radiographer at the time of your examination. You should also inform the radiographers if you have diabetes, asthma or any allergies. Despite these slight risks, your doctor believes it is advisable that you should have this examination, and do bear in mind there are greater risks from not planning your treatment accurately.

Are there any after effects?

Generally no, you can drive home afterwards and may return to work as necessary and you can eat and drink normally. If you have had an injection of contrast, we will ask you to wait about an hour before leaving the hospital to ensure you feel alright after your injection.

What is a MRI planning scan?

A MRI (magnetic resonance imaging) scan enables your health care team to gather information in order to plan your radiotherapy treatment alongside your CT planning scan.  The pictures taken are displayed on a monitor and examined by the oncologist who uses these images to plan your radiotherapy treatment.

MRI is a method of obtaining high quality images of the body without the use of ionising radiation. It is safe, totally painless, non-invasive and has no known side effects. MRI uses a large magnet, radio waves and a computer to form an image of your body which is viewed by your oncologist.

What happens during the MRI planning scan?

Like the CT scan, the MRI is also painless, though it may take a little longer, typically between 30 to 60 minutes.

Throughout the procedure you will be asked to lie on a firm couch similar to your CT planning scan, that moves in and out of the scanner, all you need to do is relax and stay still. You will be positioned on the treatment couch in the same position as your planning scan. The radiographers will then line you up with the machine and the lasers in the room to the tattoos you were given at your CT planning appointment.

You will be offered some earplugs to help reduce the noise of the scanner (a loud knocking noise).

You will also be given a small air-filled bulb to hold which, when squeezed, alerts the radiographer.

Is any preparation needed before my MRI planning appointment?

This will depend on the area of the body we are scanning.

If any preparation is needed, this will be the same as for your CT planning scan and will be explained to you in your information pack and at your CT appointment.

A full explanation of the MRI procedure will be given when you arrive for your scan. It would be appreciated if you could wear clothes without a zip fastener or metal clips etc. However, if this is a problem do not worry, you will be given a hospital gown to change into.

Some things are affected by the magnet in the MRI scanner, your radiographer will go through a questionnaire with you. If you weigh 32 stone or more, or have either a pacemaker, cochlear implant or neurostimulator please contact the radiotherapy department.

Eye make-up should be removed as this could cause a slight irritation to the eyes and may interfere with our imaging.

If you are pregnant or think you may be pregnant, please contact the radiotherapy department.

How long will the appointment take?

The length of the scan depends on the area of the body being imaged. The scanning time usually ranges from 20-30 minutes. However, there are some scans that can last up to 40 minutes.

If there is any preparation needed prior to your scan, this may take more time.

If your treatment is to the lower part of your lung, or an area in your abdomen, your breathing motion will be assessed before you attend for your planning CT session. This is carried out on the treatment unit and involves having a mini-CT scan to assess how much the tumour moves when breathing normally. We may need to use another piece of equipment which helps to control your breathing during your planning CT scan and treatment by applying gentle compression on your tummy area.

This is to increase the accuracy of your treatment.

You will also have a beanbag mould made at this appointment; you may hear us refer to this as a ‘vacbag’. This is to help you stay still and in the correct position during your CT scan and treatment.

You may be asked to attend for another scan after your planning CT session and this is carried out on the treatment unit you will be having your treatment on. This is to ensure we can reproduce your treatment set up before we proceed and start your actual treatment. We can also use this scan to help plan your treatment and adapt your treatment plan.

All of these scans give your radiotherapy team the information they need to create a personalized treatment plan for you. Here’s how these scans help:

• Locating the cancer: The scans show exactly where the tumor is located in your body. This is crucial for targeting the cancer precisely during radiotherapy, so the radiation beams can focus on the tumor and not affect the surrounding healthy tissue.

• Mapping out organs and healthy tissue: The images from these scans also show where important organs and tissues are, like your heart, lungs, or spinal cord. By knowing exactly where these structures are, your doctors can carefully plan your treatment to avoid them and reduce the risk of side effects.

• Tailoring your treatment: Using the CT and MRI images, the team can calculate the exact dose of radiation you need. They can also determine the best angles to aim the radiation beams to maximize the treatment’s effectiveness while minimizing damage to healthy tissues.

• Creating custom devices: The information from your CT or MRI scan may also be used to create custom devices, like masks or body moulds, that help you stay in the same position for every treatment session. This ensures the radiation is always aimed at the right spot.