SU-E-T-200: Impact of Detector Element-Specific Angular Correction Factors for the MaxtriXX Ion Chamber Array for Patient-Specific Dose Validation

2013 ◽  
Vol 40 (6Part13) ◽  
pp. 250-250
Author(s):  
O Casares ◽  
S Kim ◽  
J Armas ◽  
N Papanikolaou ◽  
A Gutierrez
Keyword(s):  
Patient Specific ◽  
Correction Factors ◽  
Ion Chamber ◽  
Angular Correction ◽  
Detector Element

SU-E-T-98: VMAT Quality Assurance: Improving the Angular Correction Factors for Ion Chamber Arrays

2011 ◽  
Vol 38 (6Part11) ◽  
pp. 3508-3508
Author(s):  
M Kishore ◽  
J OˈDaniel ◽  
J Bowsher ◽  
F Yin
Keyword(s):  
Quality Assurance ◽  
Correction Factors ◽  
Ion Chamber ◽  
Angular Correction

scholarly journals OC-0290 Consistency of PTW30013 and FC65-G ion chamber magnetic field correction factors

2019 ◽  
Vol 133 ◽  
pp. S144-S145
Author(s):  
S. Woodings ◽  
B. Van Asselen ◽  
T. Van Soest ◽  
L. De Prez ◽  
J. Lagendijk ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Correction Factors ◽  
Ion Chamber

PPG-BASED AUTOMATED ESTIMATION OF BLOOD PRESSURE USING PATIENT-SPECIFIC NEURAL NETWORK MODELING

2020 ◽  
Vol 20 (06) ◽  
pp. 2050037
Author(s):  
ABHISHEK CHAKRABORTY ◽  
DEBOLEENA SADHUKHAN ◽  
SAURABH PAL ◽  
MADHUCHHANDA MITRA
Keyword(s):  
Neural Network ◽  
Blood Pressure ◽  
Estimation Method ◽  
Estimation Methods ◽  
Patient Specific ◽  
Neural Network Modeling ◽  
Correction Factors ◽  
Healthcare Applications ◽  
Average Accuracy ◽  
Blood Pressure Estimation

Recently, photoplethysmography (PPG)-based techniques have been extensively used for cuff-less, automated estimation of blood pressure because of their inexpensive and effortless acquisition technology compared to other conventional approaches. However, most of the reported PPG-based, generalized BP estimation methods often lack the desired accuracy due to pathophysiological diversity. Moreover, some methods rely on several correction factors, which are not globalized yet and require further investigation. In this paper, a simple and automated systolic (SBP) and diastolic (DBP) blood pressure estimation method is proposed based on patient-specific neural network (NN) modeling. Initially, 15 time-plane PPG features are extracted and after feature selection, only four selected features are used in the NN model for beat-to-beat estimation of SBP and DBP, respectively. The proposed technique also presents reasonable accuracy while used for generalized estimation of BP. Performance of the algorithm is evaluated on 670 records of 50 intensive care unit (ICU) patients taken from MIMIC, MIMIC II and MIMIC Challenge databases. The proposed algorithm exhibits high average accuracy with (mean[Formula: see text][Formula: see text][Formula: see text]SD) of the estimated SBP as ([Formula: see text]) mmHg and DBP as ([Formula: see text]) mmHg. Compared to the other generalized models, the use of patient-specific approach eliminates the necessity of individual correction factors, thus increasing the robustness, accuracy and potential of the method to be implemented in personal healthcare applications.

scholarly journals Leaf Open Time Sinogram (LOTS):  A novel approach for Patient specific quality assurance of Total marrow irradiation

2020 ◽  
Author(s):  
Rajesh Thiyagarajan ◽  
Dayananda Shamurailatpam Sharma ◽  
Suryakant Kaushik ◽  
Mayur Sawant ◽  
Ganapathy Krishnan ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Dose Distribution ◽  
Upper Body ◽  
Patient Specific ◽  
Reconstruction Method ◽  
Ion Chamber ◽  
Modulation Factor ◽  
Novel Approach ◽  
Open Time ◽  
Total Marrow Irradiation

Abstract There is no ideal detector-phantom combination to perform patient specific quality assurance (PSQA) for total marrow (TMI) and Lymphoid (TMLI) irradiation plan. In this study, 3D dose reconstruction using mega voltage computed tomography detectors measured leaf open time sinogram (LOTS) was investigated for PSQA of TMI/TMLI patients in helical tomotherapy. The feasibility of this method was first validated for ten non-TMI/TMLI patients, by comparing reconstructed dose with a) ion-chamber (IC) and helical detector array (ArcCheck) measurement and b) planned dose distribution using 3Dγ analysis for 3%@3mm and dose to 98%(D98%) and 2%(D2%) of PTVs. Same comparison was extended for ten treatment plans from five TMI/TMLI patients. In all non-TMI/TMLI patients, reconstructed absolute dose was within ±1.8% of planned and IC measurement. The planned dose distribution agrees with reconstructed and ArcCheck measured dose with mean(SD) 3Dγ of 98.7%(1.57%) and 2Dγ of 99.48%(0.81%). The deviation in D98% and D2% were within 1.71% and 4.1% respectively. In all 25 measurement locations from TMI/TMLI patients, planned and IC measured absolute dose agrees within ±1.2%. Although sectorial fluence verification using ArcCHECK measurement for PTVs chest from five upper body TMI/TMLI plans showed mean±SD 2Dγ of 97.82%±1.27%, the reconstruction method resulted poor mean(SD) 3Dγ of 92.00%(±5.83%), 64.80%(±28.28%), 69.20%(±30.46%), 60.80%(±19.37%) and 73.2% (±20.36%) for PTVs brain, chest, torso, limb and upper body respectively. The corresponding deviation in median D98% and D2% of all PTVs were <3.8% and 9.5%. Re-optimization of all upper body TMI/TMLI plans with new pitch and modulation factor of 0.3 and 3 leads significant improvement with 3Dγ of 100% for all PTVs and median D98% and D2% <1.6%. LOTS based PSQA for TMI/TMLI is accurate, robust and efficient. A field width, pitch and modulation factor of 5cm, 0.3 and 3 for upper body TMI/TMLI plan is suggested for better dosimetric outcome and PSQA results.

scholarly journals Technical Note: Consistency of PTW30013 and FC65‐G ion chamber magnetic field correction factors

2019 ◽  
Vol 46 (8) ◽  
pp. 3739-3745
Author(s):  
S. J. Woodings ◽  
B. Asselen ◽  
T. L. Soest ◽  
L. A. Prez ◽  
J. J. W. Lagendijk ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Technical Note ◽  
Correction Factors ◽  
Ion Chamber

scholarly journals Evaluation of Delta4DVH Anatomy in 3D Patient-Specific IMRT Quality Assurance

2020 ◽  
Vol 19 ◽  
pp. 153303382094581
Author(s):  
Du Tang ◽  
Zhen Yang ◽  
Xunzhang Dai ◽  
Ying Cao
Keyword(s):  
Quality Assurance ◽  
Treatment Planning ◽  
Treatment Plan ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Pencil Beam ◽  
Ion Chamber ◽  
Passing Rate ◽  
Gamma Passing Rate

Purpose: To evaluate the performance of Delta4DVH Anatomy in patient-specific intensity-modulated radiotherapy quality assurance. Materials and Methods: Dose comparisons were performed between Anatomy doses calculated with treatment plan dose measured modification and pencil beam algorithms, treatment planning system doses, film doses, and ion chamber measured doses in homogeneous and inhomogeneous geometries. The sensitivity of Anatomy doses to machine errors and output calibration errors was also investigated. Results: For a Volumetric Modulated Arc Therapy (VMAT) plan evaluated on the Delta4 geometry, the conventional gamma passing rate was 99.6%. For a water-equivalent slab geometry, good agreements were found between dose profiles in film, treatment planning system, and Anatomy treatment plan dose measured modification and pencil beam calculations. Gamma passing rate for Anatomy treatment plan dose measured modification and pencil beam doses versus treatment planning system doses was 100%. However, gamma passing rate dropped to 97.2% and 96% for treatment plan dose measured modification and pencil beam calculations in inhomogeneous head & neck phantom, respectively. For the 10 patients’ quality assurance plans, good agreements were found between ion chamber measured doses and the planned ones (deviation: 0.09% ± 1.17%). The averaged gamma passing rate for conventional and Anatomy treatment plan dose measured modification and pencil beam gamma analyses in Delta4 geometry was 99.6% ± 0.89%, 98.54% ± 1.60%, and 98.95% ± 1.27%, respectively, higher than averaged gamma passing rate of 97.75% ± 1.23% and 93.04% ± 2.69% for treatment plan dose measured modification and pencil beam in patients’ geometries, respectively. Anatomy treatment plan dose measured modification dose profiles agreed well with those in treatment planning system for both Delta4 and patients’ geometries, while pencil beam doses demonstrated substantial disagreement in patients’ geometries when compared to treatment planning system doses. Both treatment planning system doses are sensitive to multileaf collimator and monitor unit (MU) errors for high and medium dose metrics but not sensitive to the gantry and collimator rotation error smaller than 3°. Conclusions: The new Delta4DVH Anatomy with treatment plan dose measured modification algorithm is a useful tool for the anatomy-based patient-specific quality assurance. Cautions should be taken when using pencil beam algorithm due to its limitations in handling heterogeneity and in high-dose gradient regions.

scholarly journals Direct measurement of ion chamber correction factors, k Q and k B, in a 7 MV MRI-linac

2019 ◽  
Vol 64 (10) ◽  
pp. 105025 ◽  
Author(s):  
Leon de Prez ◽  
Simon Woodings ◽  
Jacco de Pooter ◽  
Bram van Asselen ◽  
Jochem Wolthaus ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Correction Factors ◽  
Ion Chamber
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