A new approach in dose measurement and error analysis for narrow photon beams (beamlets) shaped by different multileaf collimators using a small detector

2004 ◽  
Vol 31 (7) ◽  
pp. 2020-2032 ◽  
Author(s):  
Shidong Li ◽  
Abdul Rashid ◽  
Shanjin He ◽  
David Djajaputra
Keyword(s):  
Error Analysis ◽  
Dose Measurement ◽  
Photon Beams ◽  
New Approach ◽  
Multileaf Collimators

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

A new approach for high-dose measurement using CR-39 track detector

2020 ◽  
Vol 325 (3) ◽  
pp. 765-771
Author(s):  
G. S. Sahoo ◽  
S. P. Tripathy ◽  
Rahul Roy ◽  
D. S. Joshi ◽  
M. S. Kulkarni
Keyword(s):  
Track Detector ◽  
High Dose ◽  
Dose Measurement ◽  
New Approach

A Measurement and Analysis Technique of Curves of Metal Parts

2012 ◽  
Vol 424-425 ◽  
pp. 665-668
Author(s):  
Wei Shao ◽  
Deng Xin Hua
Keyword(s):  
Error Analysis ◽  
Shape Matching ◽  
Mathematic Model ◽  
New Approach ◽  
Great Volume ◽  
Metal Parts ◽  
Analysis Technique ◽  
Measurement And Analysis ◽  
On Line ◽  
Implicit Polynomials

Metal parts with large and complicated curved surfaces used widely have some characteristics such as a great volume, a big area, distorting easily. It is very difficult to measure and evaluate accurately the parts. Taking measurement of the parts as a purpose, a new measurement method called On-Line Shape Measurement System (OSMS) is put forward.Error analysis of curves is a requirement to assure quality and to reduce manufacturing costs and rework. This paper proposes a new approach and algorithms for the error analysis of curves.the system applies a robust mathematic model, Implicit polynomials (IP), to construct the model of the test-points. Once the CAD model is adjusted, it is compared with input to reveal the errors between their shapes. To accomplish this task a new shape matching algorithm is developed. Experimental results on error analysis of a variety of the machined metal skin of aircraft are reported to show the validity of the proposed methodology.

Dose measurement at high atomic number interfaces in megavoltage photon beams using TLDs

1992 ◽  
Vol 19 (2) ◽  
pp. 355-356 ◽  
Author(s):  
A. S. Pradhan ◽  
A. K. Gopalakrishnan ◽  
P. S. Iyer
Keyword(s):  
Atomic Number ◽  
Dose Measurement ◽  
Photon Beams ◽  
High Atomic Number

Treatment Planning for Stereotactic Radiosurgery with Photon Beams

2003 ◽  
Vol 2 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Cedric Yu ◽  
David Shepard
Keyword(s):  
Stereotactic Radiosurgery ◽  
Treatment Planning ◽  
Photon Beams ◽  
Stereotactic Techniques ◽  
Multileaf Collimators ◽  
Treatment Techniques ◽  
X Band ◽  
Planning Methods ◽  
Technological Developments ◽  
Planning Strategies

Stereotactic Radiosurgery (SRS) has evolved as a unique discipline that combines aspects of both surgery and radiation oncology. Technological developments in the past few decades have provided a wide array of treatment techniques, including (i) the Gamma KnifeTM; (ii) Linac-based stereotactic techniques using circular collimators or using micro multileaf collimators (mMLCs); (iii) the Cyber KnifeTM, using an x-band linac mounted on a robotic arm; and (iv) serial and spiral tomotherapy. This paper provides a review of the treatment planning methods for stereotactic radiosurgery. Because of the differences in planning strategies used for each SRS technique, this paper will provide both a general review of the pre-requisites and common features of SRS treatment planning and the planning techniques specific to each of the SRS techniques.

SU-E-T-163: Characterization of the Response of Active Detectors and Passive Dosemeters Used for Dose Measurement in Small Photon Beams

2011 ◽  
Vol 38 (6Part12) ◽  
pp. 3523-3523 ◽  
Author(s):  
S Derreumaux ◽  
C Bassinet ◽  
C Huet ◽  
M Chea ◽  
G Boisserie ◽  
...  
Keyword(s):  
Dose Measurement ◽  
Photon Beams

Study of unflattened photon beams shaped by multileaf collimator using BEAMnrc code

2016 ◽  
Vol 15 (4) ◽  
pp. 392-401
Author(s):  
Ankit kajaria ◽  
Neeraj Sharma ◽  
Shiru Sharma ◽  
Satyajit Pradhan ◽  
Abhijit Mandal ◽  
...  
Keyword(s):  
Beam Line ◽  
Photon Beam ◽  
Field Size ◽  
Photon Beams ◽  
Multileaf Collimators ◽  
Depth Dose ◽  
Beamnrc Code ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Beam Delivery

AbstractPurposeIn our study basic dosimetric properties of a flattening filter free 6 MV photon beam shaped by multileaf collimators (MLC) is examined using the Monte Carlo (MC) method.Methods and MaterialsBEAMnrc code was used to make a MC simulation model for 6 MV photon beam based on Varian Clinic 600 unique performance linac, operated with and without a flattening filter in beam line. Dosimetric features including central axis depth dose, beam profiles, photon and electron spectra were calculated and compared for flattened and unflattened cases.ResultsDosimetric field size and penumbra were found to be smaller for unflattened beam, and the decrease in field size was less for MLC shaped in comparison with jaw-shaped unflattened beam. Increase in dose rate of >2·4 times was observed for unflattened beam indicating a shorter beam delivery time for treatment. MLC leakage was found to decrease significantly when the flattening filter was removed from the beam line. The total scatter factor showed slower deviation with field sizes for unflattened beam indicating a reduced head scatter.ConclusionsOur study demonstrated that improved accelerator characteristics can be achieved by removing flattening filter from beam line.

scholarly journals Use of Flattening Filter-Free Photon Beams in Treating Medulloblastoma: A Dosimetric Evaluation

ISRN Oncology ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Pichandi Anchineyan ◽  
Ganesh K. Mani ◽  
Jerrin Amalraj ◽  
Balaji Karthik ◽  
Surega Anbumani
Keyword(s):  
Intensity Modulated Radiation Therapy ◽  
Data Sets ◽  
Photon Beams ◽  
Treatment Efficiency ◽  
Multileaf Collimators ◽  
Conformal Therapy ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
Ct Data ◽  
Craniospinal Axis

Aim. To evaluate the dosimetric benefits of flattening filter-free (FFF) photon beams in intensity modulated radiation therapy (IMRT) and Rapid Arc (RA) over conventional CSI methods. Methods and Materials. Five patients treated with IMRT using static multileaf collimators (MLC) were randomly selected for this retrospective study. Dynamic MLC IMRT, RA, and conformal therapy (3DCRT) were iterated with the same CT data sets with and without flattening filter photons. Total dose prescribed was 28.80 Gy in 16 fractions. Dosimetric parameters such as Dmax⁡, Dmin⁡, Dmean, V95%, V107%, DHI, and CI for PTV and Dmax⁡, Dmean, V80%, V50%, V30%, and V10% for OARs were extracted from DVHs. Beam on time (BOT) for various plans was also compared. Results. FFF RA therapy (6F_RA) resulted in highly homogeneous and conformal doses throughout the craniospinal axis. 3DCRT resulted in the highest V107% (SD) 46.97±28.6, whereas flattening filter (FF) and FFF dynamic IMRT had a minimum V107%. 6F_RA and 6F_DMLC resulted in lesser doses to thyroid, eyes, esophagus, liver, lungs, and kidneys. Conclusion. FFF IMRT and FFF RA for CSI have definite dosimetric advantages over 3DCRT technique in terms of target coverage and OAR sparing. Use of FFF in IMRT resulted in 50% reduction in BOT, thereby increasing the treatment efficiency.

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