Primary content

Dedicated magnetic resonance imaging for radiotherapy planning

Authors

S Vinod (Lead)

L Holloway

E Juresic

R Rai

L Cassapi

A Xing

G Goozee

D Moses

G Liney

Aims

To describe the implementation of dedicated MRI simulation for common tumour sites treated with radiotherapy.

Method

Following installation of a 3T MRI scanner within the radiotherapy department, a multidisciplinary group devised protocols for MRI scanning specifically for radiotherapy requirements.  Volunteers were scanned to optimise scan requirements prior to clinical implementation. Input from site-specific radiation oncology groups was sought in order to refine scanning protocols.

Results

The basic requirements identified for MRI simulation were use of a flatbed couch with MRI compatible immobilisation devices, a small field of view to minimise distortion but allow adequate anatomical information for registration to CT, and thin slice thickness to allow detailed visualisation of anatomy. Patient positioning and strict bowel and bladder protocols were crucial for incorporation of MRI for radiotherapy planning. Routine MRI simulation has been successfully implemented for prostate cancer, rectal cancer, cervix cancer, head and neck cancers and brain tumours. The number of patients undergoing MRI simulation has increased from 13 patients per month (Aug-Dec 2013) to 33 patients per month (Jan-June 2014). MRI simulation is most frequently used for prostate and cervical cancer patients.

Implications

The presence of a departmental MRI simulator has allowed MRI simulation to be incorporated in many tumour sites. Better quality imaging results in improved delineation of cancers leading to more precise radiotherapy.