The effect of MV image spatial resolution on the patient positioning and patient specific QA

2021 ◽  
Vol 16 (12) ◽  
pp. T12018
Author(s):  
D. Dudas ◽  
I. Koniarova ◽  
P. Prusa ◽  
O. Koncek ◽  
P. Osmancikova ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Patient Positioning ◽  
Patient Specific ◽  
Treatment Unit ◽  
Imaging Device ◽  
Clinical Procedures ◽  
Technical Requirements ◽  
Patient Specific Qa ◽  
Imaging Performance ◽  
Radiotherapy Treatment

Abstract Electronic portal imaging device (EPID) is a common part of almost each radiotherapy treatment unit. It is a quick and simple tool for various clinical procedures, e.g. verification of patient positioning or patient specific QA. Currently available EPIDs have usually the spatial resolution below 0.5 mm. As EPIDs are not primarily designed for diagnostics, even lower spatial resolution might be acceptable. This work assesses the effect of MV image spatial resolution on clinical routines which employ the EPID and addresses the minimal technical requirements of such devices. The aim is to determine if EPIDs with poorer spatial resolution are able to reach the same clinical quality as currently used EPIDs. The effects of MV image spatial resolution on the imaging performance, patient positioning and patient specific QA were studied. The lower spatial resolution was simulated by manually downsampling the original images down to 4× poorer spatial resolution. The study includes an analysis of 96 images used for the patient positioning verification and 61 treatment field images used for the patient specific QA.

scholarly journals Planar EPID-Based Dosimetry for SRS and SRT Patient-Specific QA

Life ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1159
Author(s):  
Sangutid Thongsawad ◽  
Tadchapong Chanton ◽  
Nipon Saiyo ◽  
Nuntawat Udee
Keyword(s):  
Saturation Effect ◽  
Patient Specific ◽  
Model Accuracy ◽  
Extended Source ◽  
Imaging Device ◽  
Stereotactic Radiation ◽  
Profile Correction ◽  
Patient Specific Qa ◽  
Collimator Scatter ◽  
Good Agreement

The study’s purpose was to develop and validate Electronic Portal Imaging Device (EPID)-based dosimetry for Stereotactic Radiosurgery (SRS) and Stereotactic Radiation Therapy (SRT) patient-specific Quality Assurance (QA). The co-operation between extended Source-to-Imager Distance (SID) to reduce the saturation effect and simplify the EPID-based dosimetry model was used to perform patient-specific QA in SRS and SRT plans. The four parameters were included for converting the image to dose at depth 10 cm; dose-response linearity with MU, beam profile correction, collimator scatter and water kernel. The model accuracy was validated with 10 SRS/SRT plans. The traditional diode arrays with MapCHECK were also used to perform patient-specific QA for assuring model accuracy. The 150 cm-SID was found a possibility to reduce the saturation effect. The result of model accuracy was found good agreement between our EPID-based dosimetry and TPS calculation with GPR more than 98% for gamma criteria of 3%/3 mm, more than 95% for gamma criteria of 2%/2 mm, and the results related to the measurement with MapCHECK. This study demonstrated the method to perform SRT and SRT patient-specific QA using EPID-based dosimetry in the FFF beam by co-operating between the extended SID that can reduce the saturation effect and estimate the planar dose distribution with the in-house model.

scholarly journals Integrated multi-modality image-guided navigation for neurosurgery: open-source software platform using state-of-the-art clinical hardware

2021 ◽  
Author(s):  
Jonathan Shapey ◽  
Thomas Dowrick ◽  
Rémi Delaunay ◽  
Eleanor C. Mackle ◽  
Stephen Thompson ◽  
...  
Keyword(s):  
Skull Base ◽  
Open Source ◽  
Open Source Software ◽  
Skull Base Surgery ◽  
Patient Specific ◽  
Software Platform ◽  
Image Guided ◽  
Phantom Model ◽  
Technical Requirements ◽  
Navigated Ultrasound

Abstract Purpose Image-guided surgery (IGS) is an integral part of modern neuro-oncology surgery. Navigated ultrasound provides the surgeon with reconstructed views of ultrasound data, but no commercial system presently permits its integration with other essential non-imaging-based intraoperative monitoring modalities such as intraoperative neuromonitoring. Such a system would be particularly useful in skull base neurosurgery. Methods We established functional and technical requirements of an integrated multi-modality IGS system tailored for skull base surgery with the ability to incorporate: (1) preoperative MRI data and associated 3D volume reconstructions, (2) real-time intraoperative neurophysiological data and (3) live reconstructed 3D ultrasound. We created an open-source software platform to integrate with readily available commercial hardware. We tested the accuracy of the system’s ultrasound navigation and reconstruction using a polyvinyl alcohol phantom model and simulated the use of the complete navigation system in a clinical operating room using a patient-specific phantom model. Results Experimental validation of the system’s navigated ultrasound component demonstrated accuracy of $$<4.5\,\hbox {mm}$$ < 4.5 mm and a frame rate of 25 frames per second. Clinical simulation confirmed that system assembly was straightforward, could be achieved in a clinically acceptable time of $$<15\,\hbox {min}$$ < 15 min and performed with a clinically acceptable level of accuracy. Conclusion We present an integrated open-source research platform for multi-modality IGS. The present prototype system was tailored for neurosurgery and met all minimum design requirements focused on skull base surgery. Future work aims to optimise the system further by addressing the remaining target requirements.

PO-1399: Evaluation of SRS MapCHECK™ for SABR patient-specific QA

2020 ◽  
Vol 152 ◽  
pp. S743
Author(s):  
Y. Miao ◽  
G. Kidane ◽  
A. Ifthaker ◽  
L. Crees ◽  
E. Almond
Keyword(s):  
Patient Specific ◽  
Patient Specific Qa

Implementation of an in vivo radiochromic film QA procedure

2016 ◽  
Author(s):  
◽  
Jason Stanford
Keyword(s):  
Quality Assurance ◽  
Radiation Treatment ◽  
Radiochromic Film ◽  
In Vivo Dosimetry ◽  
Patient Specific ◽  
Attractive Alternative ◽  
Quality Assurance Procedure ◽  
Imaging Device ◽  
Treatment Techniques

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Advance treatment techniques, such as IMRT and dynamic conformal arc delivery, are novel radiation treatment procedures at the forefront of accurate and precise radiotherapy. However, the risk of suboptimal treatment resulting in injury is far greater with these techniques due to their complexity. An in vivo quality assurance system is the most appropriate validation of the delivered dose to the patient from these techniques. The intent of this research is to propose an in vivo dosimetry quality assurance procedure using radiochromic film. This research proved that radiochromic in vivo dosimetry is a viable method of detecting spatial patient specific errors in radiotherapy; however, the process is time consuming and not sensitive enough for dosimetric errors associated with weight change. Although time consuming, in vivo radiochromic dosimetry is an attractive alternative for small cancer centers and developing countries without the large startup capital to acquire the electronic portal imaging device necessary for EPID in vivo dosimetry.

scholarly journals A multi-institutional survey evaluating patient related QA – phase II

2017 ◽  
Vol 3 (2) ◽  
pp. 639-642
Author(s):  
Tobias Teichmann ◽  
Henning Salz ◽  
Michael Schwedas ◽  
Simon Howitz ◽  
Tilo Wiezorek
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Reference Conditions ◽  
Patient Specific ◽  
Beam Model ◽  
Medical Systems ◽  
Output Factor ◽  
Treatment Techniques ◽  
Patient Specific Qa ◽  
Output Factors

AbstractIn phase I of the survey a planning intercomparison of patient-related QA was performed at 12 institutions. The participating clinics created phantom based IMRT and VMAT plans which were measured utilizing the ArcCheck diode array. Mobius3D (M3D) was used in phase II. It acts as a secondary dose verification tool for patient-specific QA based on average linac beam data collected by Mobius Medical Systems. All Quasimodo linac plans will be analyzed for the continuation of the intercomparison. We aim to determine if Mobius3D is suited for use with diverse treatment techniques, if beam model customization is needed. Initially we computed first Mobius3D results by transferring all plans from phase I to our Mobius3D server. Because of some larger PTV mean dose differences we checked if output factor customization would be beneficial. We performed measurements and output factor correction to account for discrepancies in reference conditions. Compared to Mobius3D's preconfigured average beam data values, these corrected output factors differed by ±1.5% for field sizes between 7x7cm2 and 30x30cm2 and to −3.9% for 3x3cm2. Our method of correcting the output factors turns out good congruence to M3D's reference values for these medium field sizes.

scholarly journals [P134] Validation of the sunnuclear arccheck diode array for the patient specific quality assurance (PSQA) in stereotactic body radiotherapy treatment (SBRT) delivered with VMAT

2018 ◽  
Vol 52 ◽  
pp. 137-138
Author(s):  
Luca Leandro Vigna ◽  
Ashenafi Kumela Rikitu ◽  
Eleonora Monès ◽  
Federica Puricelli ◽  
Chiara Secco ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Stereotactic Body Radiotherapy ◽  
Patient Specific ◽  
Diode Array ◽  
Radiotherapy Treatment

scholarly journals A Simulation of a Novel High Quantum Efficiency Scintillating Fiber Detector with Anti-scatter Properties for Megavoltage X-Ray Imaging

2021 ◽  
Author(s):  
James Day
Keyword(s):  
Spatial Resolution ◽  
Detection Efficiency ◽  
Original Design ◽  
High Quantum Efficiency ◽  
Imaging Device ◽  
X Ray ◽  
Image Guided Radiation Therapy ◽  
X Ray Imaging ◽  
High Detection Efficiency ◽  
Square Array

To further develop a MV x-ray portal imaging device with high detection efficiency and adequate spatial resolution for image guided radiation therapy, the experimental results for a prototype detector were matched using Monte-Carlo software to then improve upon the design. The simulation and experiment were carried out using a 6 MV beam from a linear accelerator machine. An adequate match was obtained with the spatial resolution matching up to a MTF value of 0.2 and then diverging and the total signal registered in the central fiber was matched for field sizes ranging from 3 cm by 3 cm to 20 cm by 20 cm for 5 cm, 15 cm and 25 cm air gaps within 3%. The design was altered from a hexagonal array of round double cladded fibers to a square array of single cladded square fibers. The spatial resolution was improved from 0.242 lp mm-1 to 0.359 lp mm-1 at an MTF value of 0.5 from the original design to a square array of square fibers 0.5 mm wide separated by 0.25 mm of lead foil. With further optimization of the detector design it may be possible to increase spatial resolution for MV x-ray imaging while maintaining an adequate detection efficiency.

Sign in / Sign up

Export Citation Format

Share Document