Feasibility Study Into Adjustment of the Radiation Beam to Account for Prostate Motion During Radiotherapy.
Condition: Prostate Cancer
MeSH terms: Prostatic Neoplasms
Study type: Interventional

Summary: 
      The purpose of this study is to monitor movement of the prostate during radiotherapy and
      adjust the radiation beam to account for any motion seen. This will increase the radiation
      dose to the prostate and decrease the dose to the rectum and bladder.
    

Detailed description: 
      Prostate cancer now accounts for one third of all new cancer diagnoses in men and
      approximately 30% of men will have external beam radiotherapy as their primary local therapy.
      Prostate motion during radiotherapy can be divided into interfraction and intrafraction
      motion. Interfraction motion has been well established and has been largely overcome by daily
      online image verification with either ultrasound, online CT or implanted fiducial markers,
      however motion during the radiation beam on time (intrafraction motion) is not corrected and
      can be the cause of significant errors in radiation dose delivery.

      The most common technology utilised in 2012 to allow prostate gating is the Calypso system.
      The Calypso system consists of implantable electromagnetic transponders, an array that
      contains source and receiver coils, computers for data analysis and display purposes, and an
      infrared camera system to localise the electromagnetic array in the treatment room. The array
      is placed over the patient, and the source coil in the array emit an electromagnetic signal
      that excites the transponders. Once the transponders are excited, the source coils are turned
      off and the receiver coils detect the signal emitted from the excited transponders. This
      process is repeated at a rate of 10 Hz, providing a realtime radiofrequency localisation of
      the prostate triangulating three implanted beacons. The current study will investigate using
      the continuous prostate positioning data from Calypso to integrate with the treatment beam
      delivery and allow real-time adaptation based on the prostate motion. This is called Realtime
      Dynamic Multileaf Collimator (DMLC) tracking. In this technique the multileaf collimator
      motion is altered in the gantry head in real time during beam delivery to account for the
      measured prostate motion.

      The proposed study is examining the dosimetric impact of accounting for intrafraction motion
      with Calypso and DMLC tracking. We hypothesise the improvements in delivered prostate dose
      with DMLC tracking will be even greater than gating. This improved treatment delivery will
      ensure that the prostate cancer receives the appropriate dose and that normal tissues are
      spared from extra radiation.
    

Intervention name(s): Prostate cancer radiotherapy using real-time tracking
Intervention type(s): Radiation
Intervention description(s): Radiotherapy delivered using Calypso radiofrequency emitting beacon guided real-time prostate localisation and beam adjustment using Dynamic Multi-leaf Collimator tracking software.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Prostate Cancer; Real-time tracking; Radiotherapy; Dynamic Multileaf Collimator