Finding the right tests…
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Finding the right tests…
CT Scan
CT RTP stands for CT radiotherapy treatment planning, a scan used to plan radiation therapy after a cancer diagnosis has already been made. It is not a diagnostic scan; its only purpose is to map the exact location and shape of the tumour and the healthy organs nearby, so the radiation oncology team can design a treatment plan. You are scanned lying in the same position, often using the same positioning aids such as a mask or mould, that will be used for every treatment session. Small skin marks may be placed during this visit to help line you up accurately each time you return for treatment.
This scan does not measure disease severity; it maps the tumour's exact shape and location alongside nearby organs, so the radiation team can outline treatment areas and calculate doses. The images captured here become the reference used to plan and deliver every radiation session that follows.
CT RTP is done after a cancer diagnosis and after your radiation oncologist has decided that radiation therapy is part of your treatment. Its purpose is planning, not diagnosis. This visit is sometimes called a simulation, because it rehearses the exact position you will be in for treatment.
- You are positioned exactly as you will be for each treatment session, sometimes using a mask, mould, or other positioning aid - A CT scan is taken in this position - The radiation oncology team outlines the tumour and nearby organs on these images - Small skin marks, sometimes a tiny permanent tattoo, may be placed to help reproduce your position at every visit
Radiation needs to reach the tumour accurately while sparing healthy tissue around it. Because treatment is usually delivered over several sessions, the team needs a way to put you in the same position every time, and this scan is where that position is set and recorded.
CT RTP does not treat your cancer and does not replace the diagnostic scans and biopsy that led to your diagnosis. It is strictly a planning step, done once your treatment plan has already been decided.
This planning scan involves radiation exposure like any CT. A contrast injection may or may not be used, depending on your treatment area, so ask your doctor whether it applies to you.
No. CT RTP is done after diagnosis, once your doctor has already decided radiation therapy is part of your treatment. Its purpose is planning, not diagnosis.
No. It only maps the treatment area and sets your position for later radiation sessions. The actual treatment is delivered separately, over multiple visits.
Radiation needs to reach the same target precisely at every session. This scan is where your exact position is set and recorded, often using a mask or mould to help you stay still.
Small marks, sometimes a tiny permanent tattoo, help the radiation team line you up in the same position at each treatment visit.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
It depends on the area being treated and what your doctor needs to see. Ask your radiation oncology team whether contrast applies to your plan.
A diagnostic CT is used to find or characterise a condition. This scan is used only for planning already-decided radiation treatment and recording your treatment position.
It can, since positioning and outlining structures takes extra care. Ask the centre for what to expect at your specific appointment.
Preparation can vary depending on your treatment area. Ask your doctor or the radiation therapy centre for instructions.