Encrypted login | home

Program Information

Patient Specific QA On Cyberknife M6 Robotic Radiosurgery System Using In-House Fiducial Based Polystyrene Phantom

no image available
R Holla

R Holla1*, B Pillai2 , D Khanna3 , (1) Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Amrita University, India (2) Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Amrita University, India (3) Karunya University, Coimbatore, Tamilnadu


SU-I-GPD-T-537 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: Placing the Phantom and measurement chamber as per the ‘Align Centre’ chosen during the treatment planning is very challenging for Cyberknife Radiosurgery Plans involving small fields.This step plays a major role in the patient specific QA as targeting multiple beams to the chamber is based on the align center. Hence the purpose is to design a polystyrene phantom for patient specific QA on Cyberknife M6 system which uses fixed tracking method.

Methods: Three pieces of polystyrene blocks of the dimensions 20cm x 20cm x 5 cm thickness are used for designing the phantom. A chamber holder for 0.01CC pinpoint chamber (IBA, Germany) is drilled to this block such that the chamber center is at 2.5cm depth. Four numbers of stainless steel fiducials of 0.7mm diameter are implanted to this block. Two more 5cm polystyrene phantom blocks are implanted with one fiducial each making the total number of fiducials to 6. The chamber holder is sandwiched between these two blocks making the total thickness of the phantom to 15cm. 4 aligning corner screws will hold the phantom blocks together without sliding. The position of all the fiducials are such that they do not overlap in 45 and 315 degree X ray images. All fiducials are fixed in the drilled position by pouring hot wax. CT Scan of the phantom is acquired and imported to Multiplan(ACCURAY, USA). A clinical treatment plan is overlaid on this phantom and the dose is calculated. This plan is delivered to the phantom on the treatment unit using fiducial tracking method.

Results: The phantom with the chamber is accurately placed using fiducial based tracking method. The measured dose in the phantom is in agreement to the planned dose within 3%.

Conclusion: A polystyrene fiducial phantom has been designed for patient specific QA on Cyberknife M6 system.

Contact Email: