The observation of radiotherapy doses achieved when planning on an empty bladder versus a full Bladder for prostate radiotherapy treatment.

1. Empty bladder V full Bladder for prostate radiotherapy _ GenesisCare National Patient Information and Consent Form (PICF) will be given to the patients. They will have the opportunity to read the information in their own time regarding the procedure, time taken to be apart of the study and also the collection of data and any risks to the patient as part of the study. Once happy the patient can consent to the procedure if they wish to participate. 2. Radiation Oncologists will go thoroughly assess each patient who is intended for the study. They will explain the procedure and other information associated to the study. The Radiation Oncologists have a wealth of experience in this field and have submitted their up-to-date CV's to Human Research Ethics Committee (HREC). Radiation Therapists involved in the study will explain the procedure in detail with regards to the Computed Tomography scans needed. the Radiation Therapists have a wealth of experience in this field and have submitted their up-to-date CV's to HREC. 3. The mode of delivery will be face to face. The radiotherapy planning team will use the empty bladder scan and the full bladder scan to create two prostate radiotherapy plans. In doing so, differences and similarities in doses to the prostate will be observed and recorded. The use of the full bladder plan will be used as the usual standard of car for the patients treatment. For the preparation of the first CT scan, we will follow our usual full bladder protocol. We will ensure an optimally full bladder, which the patient will have to achieve during each radiotherapy treatment, which is our current standard of care. Following the first CT scan the patient will be asked to immediately empty their bladder. The patient can take as long as they need to fully empty their bladder and after doing so will then have another CT scan whilst their bladder is empty. This scan in not our current standard of care. We will use this scan to help with the planning comparison. 4. The patient will come for one radiotherapy planning scan session as per the current standard of care. The extra Computed Tomography scan will be completed on the same day if the patient agrees to participate in the study. The extra scan will take approximately 20 minutes. This research study involves exposure to a small amount of radiation. As part of everyday living, everyone is exposed to naturally occurring background radiation and receives a dose of about 2 millisieverts (mSv) each year. The effective dose from this study is about 9.5 mSv. The dose from this study is comparable to that received from many diagnostic medical x-ray and nuclear medicine procedures. At this dose level, no harmful effects of radiation have been demonstrated as any effect is too small to measure. The study team will use the data collected and observe the data over a 12 month period. 5. The study will be performed at GenesisCare Southport and GenesisCare Tugun in QLD.