Assessing the feasibility of implementing real-time multi-leaf collimator (MLC) tracking to account for the relative motion of the moving prostate tumour target and the static pelvic nodal target for high-risk prostate cancer patients. The capability of tracking for the relative motion of multiple targets will ensure that all the treatment targets receive correct dose as prescribed by the doctor and minimise side effects to the critical organs.
This study will assess the feasibility of implementing real-time multi-leaf collimator (MLC) tracking to account for the relative motion of the moving prostate tumour target and the static pelvic nodal target for high-risk prostate cancer patients. The capability of tracking for the relative motion of multiple targets will ensure that all the treatment targets receive correct dose as prescribed by the doctor and minimising side effects to the critical organs. During radiation treatment, the prostate position will be monitored in real time using the KIM technology. The nodal target will be imaged before and after each treatment to evaluate the nodal treatment margin. The MLC tracking is implemented by recalculating the radiation beam shape fit for the moved prostate and static nodal targets and sending the adjusted MLC leaf positions to the treatment delivery system. The actually delivered dose to the patient will be calculated after the treatment and compared to the dose without MLC tracking to assess the treatment efficacy.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
This intervention uses the simultaneous combined use of two technologies: 'Multi-Leaf Collimator Adaptation' and 'kV Intrafraction Monitoring'. kV Intrafraction Monitoring (KIM) measures the motion of tissues targeted for radiotherapy in real time using kV imaging.The multi-leaf collimator (MLC) reshapes the radiation beam to maximise dose to the target tissue and minimise dose to the surrounding healthy tissue. Combining KIM and MLC allows the shaped radiation beam to follow the moving target (the prostate) while remaining fixed on a stationary target (lymph nodes) that are also being treated at the same time.
Royal North Shore Hospital
St Leonards, New South Wales, Australia
Software or mechanical failure
The percentage of fractions delivered without software or mechanical failure
Time frame: The treatment period (2-9 weeks)
Geometric accuracy
The geometric accuracy of the beam shape, determined by comparing the ideal beam shape with the actual beam shape.
Time frame: The treatment period (2-9 weeks)
Prostate motion trajectory
Prostate motion trajectory measured by KIM.
Time frame: Treatment period (2-9 weeks)
Dosimetric accuracy
The estimated dose distributions will be compared to the original plan using the dose reconstruction method18 based on the prostate motion trajectory and the logged MLC positions (beam shapes).
Time frame: Treatment period (2-9 weeks)
Acute toxicity
Toxicity during treatment
Time frame: Treatment period (2-9 weeks) plus 3 months
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