Comparative Study between Measurement Data and Treatment Planning System (TPS) in Small Fields for High Energy Photon Beams

To achieve tumor control for radiotherapy, a dose distribution is planned which has a good chance of sterilizing all cancer cells without causing unacceptable normal tissue complications. The aim of the present study was to achieve an accurate calculation of dose for small field dimensions and perform this by evaluating the accuracy of planning system calculation. This will be compared with real measurement of dose for the same small field dimensions using different detectors. Practical work was performed in two steps: (i) determination of the physical factors required for dose estimation measured by three ionization chambers and calculated by treatment planning system (TPS) based on the latest technical report series (IAEATRS-398) and (ii) comparison of the calculated and measured data. Our data analysis for small field is irradiated by photon energy matched with the data obtained from the ionization chambers and the treatment planning system. Radiographic films were used as an additional detector for the obtained data and showed matching with TPS calculation. It can be concluded that studied small field dimensions were averaged 6% and 4% for 6 MV and 15 MV, respectively. Radiographic film measurements showed a variation in results within ±2% than TPS calculation.

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Two Quality Control Procedures on Radiotherapy Beam Calibration and Treatment Planning System Implementation

Tumori Journal ◽

10.1177/030089169808400210 ◽

1998 ◽

Vol 84 (2) ◽

pp. 150-154 ◽

Cited By ~ 1

Author(s):

Angelo Piermattei ◽

Luigi Azario ◽

Stefania delle Canne ◽

Andrea Fidanzio ◽

Giovanni Palazzoni

Keyword(s):

Quality Control ◽

Treatment Planning ◽

High Energy ◽

Planning System ◽

Treatment Planning System ◽

Silicon Detectors ◽

X Ray ◽

Silicon Diode ◽

Output Factors ◽

Control Procedures

New challenging dosimetric approaches, such as narrow beams and 3D algorithms, are being used in radiotherapy. In this paper two quality control (QC) procedures are reported. The first one concerns the QC of the dosimetry of small x-ray beams, generally carried out by using silicon detectors. The comparison of dose values obtained by a silicon diode, a diamond detector, and radiochromic films shows that for x-ray beams of high energy, the silicon diode can give an overestimation of the output factors in phantom, up to 4%. This is due to the higher than unit density silicon diode and the surrounding envelope that restore the lateral electron equilibrium. About the 3D algorithms for breast treatment planning, a quality control test has been adopted to verify the accuracy of the computed dosimetry when “loss of scatter” occurs. The results show a sensible agreement (within 1.5%) between computed and experimental data.

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SU-E-T-381: Evaluation of Calculated Dose Accuracy for Organs-At-Risk Located at Out-Of-Field in a Commercial Treatment Planning System for High Energy Photon Beams Produced From TrueBeam Accelerators

Medical Physics ◽

10.1118/1.4924742 ◽

2015 ◽

Vol 42 (6Part18) ◽

pp. 3421-3421

Author(s):

L Wang ◽

G Ding

Keyword(s):

Treatment Planning ◽

Organs At Risk ◽

High Energy ◽

Planning System ◽

Treatment Planning System ◽

High Energy Photon ◽

Photon Beams ◽

Energy Photon ◽

Calculated Dose ◽

Dose Accuracy

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A treatment planning system with new paradigms in the effectiveness and side-effect evaluation sections

10.21203/rs.3.rs-262580/v1 ◽

2021 ◽

Author(s):

Terman Frometa-Castillo ◽

Anil Pyakuryal ◽

Ganesh Narayanasamy ◽

Asghar Mesbahi

Keyword(s):

Treatment Planning ◽

Side Effect ◽

Normal Tissue ◽

External Beam Radiotherapy ◽

Planning System ◽

Treatment Planning System ◽

Tumor Control ◽

Tumor Control Probability ◽

Computational Simulations ◽

Linear Quadratic

Abstract Aim Academic dissemination of the “SMp treatment planning system (TPS)” for external beam radiotherapy, which has been developed as a software function that could meet the definition of a device with an entirely new intended use. This system will have new paradigms in the effectiveness and side-effect (S-E) evaluation sections, where tumor control probability (TCP) is calculated with computational simulations instead of current analytical TCP models; and S-E is evaluated with the normal tissue non-complication probability (NTCP0) methodology instead of standard NTCP one. Methods Use of probabilistic foundations in the NTCP0 methodologies; and computational simulations of the interactions of ionizing radiation with the tumor tissues in the radiation oncology treatments for the TCP calculations. Results The "TCPsim" and “NTCP0cal” calculation modules of the SMp TPS, which calculate respectively TCP and NTCP0. Conclusions While the "NTCP0cal" application has unquestionable probabilistic foundations associated to normal tissue complications as a stochastic process with more than one outcome; the "TCPsim" is based on proper approaches that are result of the computational simulations that follow logic-probabilistic procedures, and probabilistic aspects, like the relationship between TCP and linear-quadratic cell survival model for a fraction with dose d.

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