Medical Physics and Medical Physics and

RadioactivityRadioactivity

RadiotherapyRadiotherapy

Radiotherapy

• Gamma rays can kill cancer cells, but are also dangerous to healthy cells

• We need to target the gamma rays to the cancer very precisely so that the radiation dose to healthy tissue is kept to a minimum.

• In particular we need to avoid any nearby organs such as eyes or spinal cord.

Gamma Knife

The radiation has to be precisely targeted.

Metal windows restrict the gamma ray beam size

This is the Gamma Knife in position.

A polystyrene model shows the position

that the patients head would occupy.

A patient’s eye view

Planning the treatmentA medical physicist decides how to target the gamma rays to destroy

the tumour and minimise damage to other tissue

Summary

• Radiation can be dangerous so its use is carefully controlled

• In medicine, radioactive materials can be used in both diagnosis and treatment.

• Medical Physicists provide expert guidance and ensure that the radiation is controlled, measured and delivered to the benefit of the patient.

Acknowledgements

• Thanks to Emily Cook, Jeff Jones, The Nuclear Medicine Department of The Royal Free Hospital, London, and The Cromwell Gamma Knife Centre, London for providing images

• This lesson was developed by Adam Gibson, Jeff Jones, David Sang, Angela Newing, Nicola Hannam and Emily Cook

• We have attempted to obtain permission and acknowledge the contributor of every image. If we have inadvertently used images in error, please contact us.