scholarly journals Comparison of biological-based and dose volume-based intensity-modulated radiotherapy plans generated using the same treatment planning system

2019 ◽  
Vol 15 (8) ◽  
pp. 33 ◽  
Author(s):  
KJ Maria Das ◽  
K Senthilkumar
Keyword(s):  
Treatment Planning ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Intensity Modulated ◽  
Dose Volume

scholarly journals Intensity modulated radiotherapy using Monte Carlo for routine postmastectomy radiotherapy

2012 ◽  
Vol 18 (2) ◽  
pp. 49-58
Author(s):  
Hiba Baha Eldin Sayed Omer
Keyword(s):  
Monte Carlo ◽  
Treatment Planning ◽  
Intensity Modulated Radiotherapy ◽  
Response To Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Planning Systems ◽  
Dose Volume Histograms ◽  
Intensity Modulated ◽  
Treatment Planning Systems

Radiotherapy given after mastectomy (PMRT) will reduce the risk of local recurrence by about two-thirds. Clinical and dosimetric trials were carried out using various techniques to optimize the treatments by maximizing the dose to the tumour and minimizing it to the healthy tissues at proximity. Different conventional techniques which have been studied suffer from important dose inhomogeneities due to the complex anatomy of the chest, which reduces the benefits from such treatments. Moreover, due to the heterogeneity of breast cancer, the response to therapy and a systematic approach to treatment cannot be derived and treatment regimens must be determined on a patient-by-patient basis. This is only possible if accurate and fast treatment planning systems are available. Intensity Modulated Radiotherapy (IMRT) allows delivering higher doses to the target volume and limits the doses to the surrounding tissues. The objective of this study is to test the feasibility of applying a Monte Carlo-based treatment planning system, Hyperion accurately in routine Intensity Modulated Radiotherapy (IMRT) postmastectomy. In order to use a treatment planning system for routine work it should prove to provide optimized dose delivery in a suitable time. Treatment planning for IMRT application to PMRT was performed using Hyperion. Constraints were set to deliver the prescribed dose to the target and minimize the dose to the organs at risk. Dose Volume Histograms (DVH) were used to evaluate the set up plans. Time taken to optimize the plan was measured. The target coverage was within the accepted values. Approximately 90% of the breast and 80% of the PTV received 45 Gy or above. The volume of the lung that received 40Gy was less than 10% and the volume that received 20Gy (V20) was less than 25%. The volume of the heart receiving 30 Gy (V30) or above was negligible. This indicates low NTCP of these organs. The time taken for optimization, showed it possible to apply Monte Carlo-based treatment-planning systems for patient-to-patient PMRT.

scholarly journals Implementation of compensator-based intensity modulated radiotherapy with a conventional telecobalt machine using missing tissue approach

2018 ◽  
Vol 24 (4) ◽  
pp. 171-179
Author(s):  
Samuel N. A. Tagoe ◽  
Samuel Y. Mensah ◽  
John J. Fletcher
Keyword(s):  
Treatment Planning ◽  
Specific Treatment ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Distributions ◽  
Intensity Modulated ◽  
Limit Value ◽  
Tissue Equivalent ◽  
Tissue Equivalent Phantom

Abstract Objectives: The present study aimed to generate intensity-modulated beams with compensators for a conventional telecobalt machine, based on dose distributions generated with a treatment planning system (TPS) performing forward planning, and cannot directly simulate a compensator. Materials and Methods: The following materials were selected for compensator construction: Brass, Copper and Perspex (PMMA). Boluses with varying thicknesses across the surface of a tissue-equivalent phantom were used to achieve beam intensity modulations during treatment planning with the TPS. Beam data measured for specific treatment parameters in a full scatter water phantom with a 0.125 cc cylindrical ionization chamber, with a particular compensator material in the path of beams from the telecobalt machine, and that without the compensator but the heights of water above the detector adjusted to get the same detector readings as before, were used to develop and propose a semi-empirical equation for converting a bolus thickness to compensator material thickness, such that any point within the phantom would receive the planned dose. Once the dimensions of a compensator had been determined, the compensator was constructed using the cubic pile method. The treatment plans generated with the TPS were replicated on the telecobalt machine with a bolus within each beam represented with its corresponding compensator mounted on the accessory holder of the telecobalt machine. Results: Dose distributions measured in the tissue-equivalent phantom with calibrated Gafchromic EBT2 films for compensators constructed based on the proposed approach, were comparable to those of the TPS with deviation less than or equal to ± 3% (mean of 2.29 ± 0.61%) of the measured doses, with resultant confidence limit value of 3.21. Conclusion: The use of the proposed approach for clinical application is recommended, and could facilitate the generation of intensity-modulated beams with limited resources using the missing tissue approach rendering encouraging results.

Quality assurance of intensity-modulated radiotherapy treatment planning: a dosimetric comparison

2018 ◽  
Vol 17 (4) ◽  
pp. 396-402 ◽  
Author(s):  
Saima Altaf ◽  
Khalid Iqbal ◽  
Muhammad Akram ◽  
Saeed A. Buzdar
Keyword(s):  
Quality Assurance ◽  
Radiation Therapy ◽  
Treatment Planning ◽  
Intensity Modulated Radiotherapy ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Imaging Device ◽  
Intensity Modulated ◽  
Passing Rates

AbstractAimThe purpose of this study was to analyse the comparison of intensity-modulated radiation therapy quality assurance (IMRT QA) using Gafchromic® EBT3 film, Electronic portal imaging device (EPID) and MapCHECK®2.BackgroundPretreatment authentication is the main apprehension in advanced radiation therapy treatment plans such as IMRT.Materials and methodsA total of 20 patients were planned on Eclipse treatment planning system using 6 and 15 MV separately.ResultsGamma index of EBT3 film results shows the following average passing rates: 97% for 6 MV and 96·6% for 15 MV using criteria of ±5% of 3 mm, ±3% of 3 mm and ±3% of 2 mm for brain. However, by using ±5% of 3 mm and ±3% of 3 mm criteria, the average passing rates were 95·4% on 6 MV and 95·2% on 15 MV for prostate. For EPID, the results show the average passing rates as 97·8% for 6 MV and 97·2% for 15 MV in for brain. In cases in which ±5% of 3 mm and ±3% of 3 mm were used, the average passing rates were 96·6% for 6 MVand 96·1% for 15 MV for prostate. MapCHECK®2 results show average passing rates of 96·4% for 6 and 96·2% for 15 MV, respectively, for brain using criteria of ±5% of 3 mm, ±3% of 3 mm and ±3% of 2 mm, whereas for ±5% of 3 mm and ±3% of 3 mm the average rates are 95·2% for 6 and 94·7% for 15 MV in prostate.ConclusionsThe EPID results are better than the other methods, and hence EPID can be used effectively for IMRT pretreatment verifications.

scholarly journals Dosimetric evaluation of cobalt-60 teletherapy in advanced radiation oncology

2018 ◽  
Vol 18 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Manny Mathuthu ◽  
Nhlakanipho Wisdom Mdziniso ◽  
Yihunie Hibstie Asres
Keyword(s):  
Three Dimensional ◽  
Intensity Modulated Radiotherapy ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Solid State Drives ◽  
Water Phantom ◽  
Intensity Modulated ◽  
Gafchromic Ebt2 Film ◽  
Ebt2 Film

AbstractBackgroundRecent investigations demonstrate a strong potential for cobalt-60 (Co-60)-based teletherapy. The influence of the lower energy and penetration of a cobalt-60 beam compared with linear accelerator beams is negligible for intensity-modulated radiotherapy.PurposeThe aim of this research is to investigate source head fluence modulation in cobalt-60 teletherapy by using a three-dimensional (3D) physical compensator and secondary collimator jaw motion.Materials and methodsThe Oncentra treatment planning system was used to develop three hypothetical plans by secondary collimator jaw motion. A clinical MDS Nordion Equinox 80 cobalt-60 teletherapy unit was used to acquire conventional water phantom beam characteristics. Fluence modulation experiments were executed at 5·0 cm depth in a PTW universal intensity-modulated radiation therapy (IMRT) verification phantom using calibrated Gafchromic external beam therapy 2 (EBT2) and RTQA2-1010 film batches. Gafchromic EBT2 film was used to sample intensity maps generated by secondary collimator jaw motion, yet Gafchromic RTQA2-1010 film sampled maps from the 3D physical compensator. The solid-state drives used were 75·0 and 74·3 cm for the Gafchromic EBT2 and Gafchromic RTQA2-1010 film measurements.ResultsA 2D gamma index analysis was coded to compare EBT2 film measurements with Digital Imaging and Communications in Medicine data. This analysis was also used to verify film measurements versus Monte-Carlo simulations.ConclusionLateral beam profiles generated from water phantom measurements were used to establish source head fluence modulation on the film measurements. The source head fluence of a cobalt-60 teletherapy beam could be modulated by secondary collimator jaw motion and using a 3D physical compensator.

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