scholarly journals Dosimetric comparison between 3D conformal and intensity-modulated radiation therapy for prostate cancer

2010 ◽  
Vol 9 (2) ◽  
pp. 77-85 ◽  
Author(s):  
Courtney Buckey ◽  
Gregory Swanson ◽  
Sotirios Stathakis ◽  
Nikos Papanikolaou
Keyword(s):  
Radiation Therapy ◽  
Organs At Risk ◽  
External Beam Radiotherapy ◽  
Radiation Therapy Oncology Group ◽  
Intensity Modulated Radiation Therapy ◽  
Standard Of Care ◽  
Target Volume ◽  
Conformal Radiation Therapy ◽  
Intensity Modulated ◽  
3D Crt

AbstractBackground and Purpose: Intensity-modulated radiation therapy (IMRT) is considered by many to be the standard of care in the delivery of external-beam radiotherapy treatments to the prostate. The purpose of this study is to assess the validity of the purported benefits of IMRT.Materials and Methods: Treatment plans were produced for 10 patients using both 3D conformal radiation therapy (3D-CRT) and IMRT, utilising the dose constraints recommended by the Radiation Therapy Oncology Group (RTOG) 0415 protocol. Three IMRT modalities used in this study were linear accelerator based IMRT, helical tomotherapy, and serial tomotherapy. The prescription to the target, 76 Gy, was the same for all plans.Results: In general the 3D-CRT plans satisfied the RTOG criteria for planning target volume (PTV) coverage, and met or bettered the dose criteria for the organs at risk. PTV coverage was more homogeneous for the IMRT plans than the 3D-CRT plans but not significantly improved.Conclusions: Technically, because the IMRT plans required greater effort for the optimisation, longer treatment times and higher monitor units, the use of IMRT for the fulfilment of the protocol’s dosimetric goals was not justified using these constraints.

Intensity-modulated radiation therapy (IMRT): Differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma.

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 586-586
Author(s):  
H. Mok ◽  
C. H. Crane ◽  
T. Briere ◽  
S. Beddar ◽  
M. E. Delclos ◽  
...  
Keyword(s):  
At Risk ◽  
Rectal Cancer ◽  
Radiation Therapy ◽  
Small Bowel ◽  
Rectal Carcinoma ◽  
Organs At Risk ◽  
Intensity Modulated Radiation Therapy ◽  
Preoperative Treatment ◽  
Conformal Radiation Therapy ◽  
Intensity Modulated

586 Background: In the treatment of rectal cancer, a strong dose-volume relationship exists between the amount of small bowel receiving low- to intermediate-doses of radiation and the rates of acute, severe gastrointestinal toxicity. Highly conformal treatment approaches, such as intensity-modulated radiation therapy (IMRT), may reduce dose to adjacent organs-at-risk (OAR). We performed a dosimetric evaluation of IMRT compared to 3-dimensional conformal radiation therapy (3DCRT) in standard, preoperative treatment for rectal cancer. Methods: Using RTOG consensus contouring atlas, treatment volumes were generated for ten patients treated preoperatively, with IMRT plans compared to 3DCRT plans derived from classic anatomic landmarks, as well as modified 3DCRT plans treating the RTOG consensus volume. The patients were all T3, were node-negative (N=1) or node–positive (N=9), and were planned to a total dose of 45-Gy. Bowel displacement was achieved using a carbon-fiber bellyboard apparatus with prone positioning. Results: IMRT plans had superior PTV coverage, dose homogeneity, and conformality in treatment of the gross disease and at-risk nodal volume, in comparison to 3DCRT. Additionally, in comparison to the modified 3DCRT plans, IMRT achieved a concomitant reduction in doses to the bowel, bladder, pelvic bones, and femoral heads, with an improvement in absolute volumes of small bowel receiving dose levels known to induce clinically-relevant acute toxicity. In the six patients with the highest volume of small bowel (range: 209-537-cc), the volume of bowel receiving 15-Gy was reduced from a median of 224-cc in the modified 3DCRT plans to 185-cc with IMRT. Also, the IMRT volumes were typically larger than that covered by classic 3DCRT fields, without incurring penalty with respect to adjacent OAR. Conclusions: For rectal carcinoma, IMRT, compared to 3DCRT, yielded plans with superior target coverage, homogeneity, and conformality, while lowering dose to adjacent OAR. This is despite treating larger volumes, raising the possibility of a clinically-relevant improvement in the therapeutic ratio through the use of IMRT with a belly-board apparatus. No significant financial relationships to disclose.

A planning study to optimise a simultaneously integrated boost treatment of larynx cancer with seven intensity-modulated radiation therapy (IMRT) beams

2018 ◽  
Vol 17 (4) ◽  
pp. 447-454 ◽  
Author(s):  
M. Erraoudi ◽  
M. A. Youssoufi ◽  
F. Bentayeb ◽  
M. R. Malisan
Keyword(s):  
Radiation Therapy ◽  
Organs At Risk ◽  
Intensity Modulated Radiation Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
The Body ◽  
Larynx Cancer ◽  
Body Volume ◽  
Intensity Modulated ◽  
Integrated Boost

AbstractBackgroundIntensity-modulated radiation therapy (IMRT) is one of the most reported techniques for head and neck cancer treatment, as it allows a good coverage of the planning target volume (PTV) while sparing the surrounding organs at risk (OAR) better than conventional conformal radiotherapy. The objective of this work is to optimise an IMRT technique for the simultaneously integrated boost (SIB) treatment of larynx cancer delivering a total dose of 69·96 Gy to the boost volume and 54·45 Gy to the elective volume in 33 fractions.MethodsThree IMRT techniques, each using seven equally spaced beams, were planned for a sample of 10 patients. The first two techniques (IMRT-0 and IMRT-26) differ only for the starting angle of the seven beams, whereas the third (IMRT-CT) combines both these techniques by delivering IMRT-0 in the first half of treatment, and IMRT-26 in the second half, thus taking advantage of using 14 beams in total while using seven at a time only. The planning results were compared according to the dose coverage, homogeneity and conformity of the two PTVs, as well as to the dose to OARs, that is, spinal cord, parotids, mandible, brainstem and healthy tissue (defined as the body volume minus the sum of PTVs).ResultsBasically the PTV coverage resulted acceptable and comparable with all the three techniques. Concerning OARs, statistically better results are obtained in IMRT-CT when compared with IMRT-26 and IMRT-0.ConclusionThe IMRT-CT technique, combining two different seven-beam setups, delivered in two treatment phases, improves dose distribution without increasing delivery time.

scholarly journals A dummy-run evaluation of postoperative hypofractionated intensity-modulated radiation therapy (POHIM-RT) trials for cervical cancer

2020 ◽  
Vol 62 (1) ◽  
pp. 149-154
Author(s):  
Won Kyung Cho ◽  
Heejung Kim ◽  
Won Park ◽  
Sang-Won Kim ◽  
Jongwon Kim ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Quality Assurance ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Similarity Coefficients ◽  
Intensity Modulated ◽  
And Performance

Abstract The postoperative hypofractionated intensity-modulated radiation therapy (POHIM-RT) trial is a phase II study to evaluate toxicity following hypofractionated intensity modulated radiation therapy (IMRT) for cervical cancer. This study describes the results of a benchmark procedure for RT quality assurance of the POHIM-RT trial. Six participating institutions were provided computed tomography for RT planning and an IMRT plan for a sample and were instructed to delineate volumes, create a treatment plan and quality assurance (QA) plan, and submit the results of all procedures. The inter-institutional agreements on RT volume and plan results were evaluated using the kappa value and dice similarity coefficients. The simultaneous truth and performance level estimation (STAPLE) method was employed to generate a consensus target volume. The treatment volumes, organs-at-risk volumes, and results of the RT plan and QA reported by the institutions were acceptable and adhered well to the protocol. In terms of clinical target volume (CTV) delineation, there were differences between the institutions, particularly in vaginal cuff and paracolpium subsites. Consensus CTV was generated from the collected CTVs with the STAPLE method. The participating institutions showed considerable agreement regarding volume, dose and QA results. To improve CTV agreement in CTV, we provided feedback with images of the consensus target volume and detailed written guidelines for specific subsites that were the most heterogeneous.

scholarly journals Intensity Modulated and Three-Dimensional Conformal Radiation Therapy Plans for Oropharyngeal Cancer: A Comparison of Their Sensitivity to Set-Up Errors and Uncertainties

2011 ◽  
Vol 13 (2) ◽  
pp. 61-66
Author(s):  
N. Ploquin ◽  
H. Lau ◽  
P. Dunscombe
Keyword(s):  
Radiation Therapy ◽  
Radiation Therapy Oncology Group ◽  
Three Dimensional ◽  
Imrt Plan ◽  
Data Set ◽  
Conformal Radiation Therapy ◽  
Intensity Modulated ◽  
Treatment Plans ◽  
Set Up ◽  
3D Crt

We compared the effect of set-up error and uncertainty on two radiation therapy treatment plans for head and neck cancer: one using intensity modulated radiation therapy (IMRT) and one using conventional three-dimensional conformal radiation therapy (3D-CRT). We used a Pinnacle3 (Philips Medical Systems, Markham, Ontario) system to create the two treatment plans (7-beam IMRT and 5-beam 3D-CRT) for the same volumetric data set, based on the objectives and constraints defined in the Radiation Therapy Oncology Group H-0022 protocol. In both plans, the dose–volume constraints for the targets and the organs at risk (OARS) were met as closely as the beam geometries would allow. Monte Carlo–based simulations of set-up error and uncertainty were performed in three orthogonal directions for 840 simulated “courses of treatment” for each plan. A systematic error (chosen from distributions characterized by standard deviations ranging from 0 mm to 6 mm) and random uncertainties (2 mm standard deviation) were incorporated. We used a probability approach to compare the sensitivities of the IMRT and the 3D-CRT plans to set-up error and uncertainty in terms of equivalent uniform dose (EUD) to targets and OARS. Based on the EUD analysis, the targets and OARS showed considerably greater sensitivity to set-up error with the IMRT plan than with the 3D-CRT plan. For the IMRT plan, target EUDS were reduced by 4%, 7.5%, and 10% for 2-mm, 4-mm, and 6-mm set-up errors respectively. However, even with set-up error, the mandible, spinal cord, and parotid EUDS always remained lower with the IMRT plan than with the 3D-CRT plan. We conclude that, when quantified by EUD, IMRT plan doses to OARS and targets are more sensitive to set-up error than are 3D-CRT-plan doses. However, as judged by the differences between target and OAR doses, IMRT retains its superiority over 3D-CRT, even in the presence of set-up error.

Development and evaluation of a Perspex anthropomorphic head and neck phantom for three dimensional conformal radiation therapy (3D-CRT)

2013 ◽  
Vol 12 (3) ◽  
pp. 272-280 ◽  
Author(s):  
Khaldoon M. Radaideh ◽  
Laila M. Matalqah ◽  
A. A. Tajuddin ◽  
W. I. Fabian Lee ◽  
S. Bauk ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Head And Neck ◽  
Organs At Risk ◽  
Radiation Therapy Oncology Group ◽  
Repeated Measurements ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformal Radiation Therapy ◽  
Good Agreement ◽  
3D Crt

AbstractPurposesTo design, construct and evaluate an anthropomorphic head and neck phantom for the dosimetric evaluation of 3D-conformal radiotherapy (3D-CRT) dose planning and delivery, for protocols developed by the Radiation Therapy Oncology Group (RTOG).Materials and methodsAn anthropomorphic head and neck phantom was designed and fabricated using Perspex material with delineated planning target volumes (PTVs) and organs at risk (OARs) regions. The phantom was imaged, planned and irradiated conformally by a 3D-CRT plan. Dosimetry within the phantom was assessed using thermoluminescent dosimeters (TLDs). The reproducibility of phantoms and TLD readings were checked by three repeated identical irradiations. Subsequent three clinical 3D-CRT plans for nasopharyngeal patients have been verified using the phantom. Measured doses from each dosimeter were compared with those acquired from the treatment planning system (TPS).ResultsPhantom's measured doses were reproducible with <3·5% standard deviation between the three TLDs’ repeated measurements. Verification of three head and neck 3D-CRT patients’ plans was implemented, and good agreement between measured values and those predicted by TPS was found. The percentage dose difference for TLD readings matched those corresponding to the calculated dose to within 4%.ConclusionThe good agreement between predicted and measured dose shows that the phantom is a useful and efficient tool for 3D-CRT technique dosimetric verification.

scholarly journals Modelling the effects of lung cancer motion due to respiration

Nukleonika ◽  
2018 ◽  
Vol 63 (4) ◽  
pp. 95-103 ◽  
Author(s):  
Marta Adamczyk ◽  
Sebastian Adamczyk ◽  
Tomasz Piotrowski
Keyword(s):  
Lung Cancer ◽  
Radiation Therapy ◽  
Three Dimensional ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Conformal Radiation Therapy ◽  
Motion Patterns ◽  
Intensity Modulated ◽  
Motion Kernel ◽  
Static Conditions

Abstract Background and objectives: To justify the concept of validating conformal versus intensity-modulated approach in the treatment of non-small cell lung cancer (NSCLC). Materials and methods: For 10 patients representative of the spectrum of tumour sizes and locations, two plans were prepared: one with three-dimensional conformal radiation therapy (3DCRT) technique and the other with intensity-modulated radiation therapy (IMRT) technique. Preliminary measurements were performed in static conditions. For each of the field angles considered, the motion kernel was generated to simulate tumour motion trajectories, with the largest amplitude in the cranio-caudal direction of 4, 6, and 8 mm. The measurement results determined the agreement between the planned and measured doses. Results: No statistically significant differences were found between the motion patterns, with the smallest amplitudes for clinical target volume in 3DCRT. For IMRT, the significant differences between 0 mm vs. 6 mm and 0 mm vs. 8 mm amplitudes were found. The motion impact on delivered vs. planned doses had less effect on the oesophagus in 3DCRT compared to that in IMRT. The observed differences were comparable for the heart. Interpretation and conclusions: For maximal amplitudes below 4 mm, the disagreement between planned and delivered doses can be neglected. However, the amplitudes above 5 mm and 7 mm lead to significant changes in IMRT and 3DCRT dose distribution, respectively.

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