Inclusion Criteria:

- Hormone therapy naive patients planned to be treated by radical radiotherapy after
3-6 months of androgen suppression

- Patients with low-high risk histologically confirmed localised disease are eligible,
with WHO performance status 0-1.

Exclusion Criteria:

- Patients unsuitable for functional MRI of the prostate or gold seed fiducial marker
insertion (e.g. patients unable to tolerate endorectal MRI examination).

- No prior pelvic radiotherapy or radical prostatectomy, previous androgen therapy,
patients unsuitable for radical radiotherapy, life expectancy <10 years, previous
active malignancy within last 5 years, co-morbid conditions likely to impact on the
advisability of radical radiotherapy, full anticoagulation, other exclusions to MRI
(e.g. hip prosthesis or fixation, claustrophobia, ferromagnetic implants).