Method to predict respiratory-induced motion of the prostate during radiotherapy for prostate cancer patients treated with image-guided radiation therapy (IGRT), and to convert an existing prostate tracking technology into a respiratory gauge.
- Provides individualized treatment method for radiation therapy via respiratory gating capabilities.
- Converts existing prostate or any organ tracking device into a potentially respiratory status monitory (i.e. dual purpose device).
- Predicts patient-specific prostate motion for treatment planning with multi-fractionated intensity modulated radiotherapy (IMRT).
- Increased accuracy than conventional fixed treatment margin approaches which do not account for natural prostate motion.
Prostate cancer is the most common cancer in American men. Recent trends in imaging software and radiotherapy have been to improve treatment planning, specifically treatment margins, while simultaneously increasing safety and accuracy for the patient during radiation. The prostate moves both between fractions of treatment (inter-fraction) and during treatment fractions themselves (intra-fraction) so there is a margin of error added around the clinical target volume to be treated. Although there are a number of methods to reduce the error associated with the motion of the prostate, none of these processes are individualized in order to develop patient-specific margins. Furthermore, existing prostate localization and intra-fraction organ tracking devices do not monitor respiratory distress or patient level of anxiety during treatment, which may influence intra-fraction organ motion due to changes in respiratory patterns during treatment.
Emory researchers have found that respiration affects prostate motion, and developed a method to extract and isolate the respiratory-induced prostate motion from total prostate movement. Real-time intra-fraction data are sensitive enough to measure the impact of respiration using wavelet decomposition methods. Respiratory-induced motion ranged between 0.2 and 2 mm in 99% of patients. Although the average respiratory amplitude was small, this method provides a tool that can aid in the creation of individualized, or patient-specific, treatment margins while accounting for changes in patient’s respiratory distress.
Study was completed using data from 31 prostate cancer patients.
Lin et al., 2013. Int J Radiat Oncol Biol Phys. 87: 370-374.
Liet et al., 2013. Int J Radiat Oncol Biol Phys. 87:363-69.