Verification of an optimizer algorithm by the beam delivery evaluation of intensity-modulated arc therapy plans

Abstract Background In the case of dynamic radiotherapy plans, the fractionation schemes can have dosimetric effects. Our goal was to define the effect of the fraction dose on the plan quality and the beam delivery. Materials and methods Treatment plans were created for 5 early-stage lung cancer patients with different dose schedules. The planned total dose was 60 Gy, fraction dose was 2 Gy, 3 Gy, 5 Gy, 12 Gy and 20 Gy. Additionally renormalized plans were created by changing the prescribed fraction dose after optimization. The dosimetric parameters and the beam delivery parameters were collected to define the plan quality and the complexity of the treatment plans. The accuracy of dose delivery was verified with dose measurements using electronic portal imaging device (EPID). Results The plan quality was independent from the used fractionation scheme. The fraction dose could be changed safely after the optimization, the delivery accuracy of the treatment plans with changed prescribed dose was not lower. According to EPID based measurements, the high fraction dose and dose rate caused the saturation of the detector, which lowered the gamma passing rate. The aperture complexity score, the gantry speed and the dose rate changes were not predicting factors for the gamma passing rate values. Conclusions The plan quality and the delivery accuracy are independent from the fraction dose, moreover the fraction dose can be changed safely after the dose optimization. The saturation effect of the EPID has to be considered when the action limits of the quality assurance system are defined.

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High-dose-rate brachytherapy for vaginal cancer: Learning from treatment complications

International Journal of Gynecological Cancer ◽

10.1136/ijgc-00009577-200201000-00005 ◽

2002 ◽

Vol 12 (1) ◽

pp. 27-31

Author(s):

W. C Tyree ◽

H Cardenes ◽

M Randall ◽

L Papiez

Keyword(s):

Dose Rate ◽

Late Effects ◽

Early Stage ◽

High Dose Rate ◽

Vaginal Cancer ◽

High Dose ◽

Hdr Brachytherapy ◽

High Dose Rate Brachytherapy ◽

Treatment Complications ◽

Treatment Plans

Abstract.Tyree WC, Cardenes H, Randall M, Papiez L. High-dose-rate brachytherapy for vaginal cancer: learning from treatment complications.Historically, early stage vaginal cancer has been treated with low-dose-rate (LDR) brachytherapy with or without external beam radiation therapy (EBRT). Complication rates have been low and treatment efficacious. Although high-dose-rate (HDR) brachytherapy has been used for cervical cancer in many countries for over a decade, only more recently has it been integrated into treatment plans for vaginal cancer. This paper describes three patients treated with HDR brachytherapy who experienced significant late effects. Given the very limited amount of literature regarding the use of HDR brachytherapy in vaginal cancer, this analysis potentially contributes to an understanding of treatment-related risk factors for complications among patients treated with this modality.A focused review of hospital and departmental treatment records was done on three patients treated with HDR brachytherapy. Abstracted information included clinical data, treatment parameters (technique, doses, volume, combinations with other treatments) and outcomes (local control, survival, early and late effects). A review of the available literature was also undertaken.All patients had significant complications. Although statistical correlations between treatment parameters and complications are impossible given the limited number of patients, this descriptive analysis suggests that vaginal length treated with HDR brachytherapy is a risk factor for early and late effects, that the distal vagina has a lower radiation tolerance than the upper vagina with HDR as in LDR, and that combining HDR with LDR as done in our experience carries a high risk of late toxicity.Integration of HDR brachytherapy techniques into treatment plans for early stage vaginal cancers must be done cautiously. The etiology of the significant side effects seen here is likely to be multifactorial. For users of HDR brachytherapy in vaginal cancer, there is a need to further refine and standardize treatment concepts and treatment delivery. Ideally this will be based on continued careful observation and reporting of both favorable and unfavorable outcomes and experiences.

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Retrospective analysis of portal dosimetry pre-treatment quality assurance of hybrid IMRT breast treatment plans

Journal of Radiotherapy in Practice ◽

10.1017/s1460396920000072 ◽

2020 ◽

pp. 1-8

Author(s):

Meghan Koo ◽

Johnson Darko ◽

Ernest Osei

Keyword(s):

Quality Assurance ◽

Treatment Quality ◽

Control Points ◽

Calculation Algorithm ◽

Positioning Errors ◽

Passing Rate ◽

Portal Dosimetry ◽

Treatment Plans ◽

Pre Treatment ◽

Gamma Passing Rate

Abstract Background: The purpose of this study is to evaluate the effectiveness and sensitivity of the Varian portal dosimetry (PD) system as a quality assurance (QA) tool for breast intensity-modulated radiation therapy (IMRT) treatment plans. Materials and methods: Four hundred portal dose images from 200 breast cancer patient IMRT treatment plans were analysed. The images were obtained using Varian PortalVision electronic portal imaging devices (EPIDs) on Varian TrueBeam Linacs. Three patient plans were selected, and the multi-leaf collimator (MLC) positions were randomly altered by a mean of 0·5, 1, 1·5 and 2 mm with a standard deviation of 0·1 mm on 50, 75 and 100% of control points. Using the improved/global gamma calculation algorithm with a low-dose threshold of 10% in the EPID, the change in gamma passing rates for 3%/3 mm, 2%/2 mm and 1%/1 mm criterion was analysed as a function of the introduced error. The changes in the dose distributions of clinical target volume and organ at risk due to MLC positioning errors were also analysed. Results: Symmetric and asymmetric breast or chest wall plan fields are different in delivery as well as in the QA. An average gamma passing rate of 99·8 ± 0·5 is presented for 3%/3 mm symmetric plans and 96·9 ± 4·5 is presented for 3%/3 mm asymmetric plans. An average gamma passing rate of 98·4 ± 4·3 is presented for 2%/2 mm symmetric plans and 89·7 ± 9·5 is presented for 2%/2 mm asymmetric plans. A large-induced error in MLC positioning (2·0 mm, 100% of control points) results in an insignificant change in dose that would be delivered to the patient. However, EPID portal dosimetry is sensitive enough to detect even the slightest change in MLC positioning error (0·5 mm, 50% of control points). Conclusions: Stricter pre-treatment QA action levels can be established for breast IMRT plans utilising EPID. For improved sensitivity, a multigamma criteria approach is recommended. The PD tool is sensitive enough to detect MLC positioning errors that contribute to even insignificant dose changes.

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PD-0323 TOMOTHERAPY TREATMENT PLAN QUALITY ASSURANCE (QA): THE IMPACT OF APPLIED CRITERIA ON GAMMA PASSING RATE (%GP)

Radiotherapy and Oncology ◽

10.1016/s0167-8140(12)70662-x ◽

2012 ◽

Vol 103 ◽

pp. S128

Author(s):

A. Di Dia ◽

C. Sini ◽

S. Bresciani ◽

A. Maggio ◽

A. Miranti ◽

...

Keyword(s):

Quality Assurance ◽

Treatment Plan ◽

Plan Quality ◽

Passing Rate ◽

The Impact ◽

Gamma Passing Rate

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Dosimetric comparison between dynamic wave arc and co-planar volumetric modulated radiotherapy for locally advanced pancreatic cancer

10.21203/rs.3.rs-60459/v2 ◽

2020 ◽

Author(s):

Alshaymaa Abdelghaffar ◽

Noriko Kishi ◽

Ryo Ashida ◽

Yukinori Matsuo ◽

Hideaki Hirashima ◽

...

Keyword(s):

Pancreatic Cancer ◽

Spinal Cord ◽

Locally Advanced ◽

Advanced Pancreatic Cancer ◽

Locally Advanced Pancreatic Cancer ◽

Dose Distributions ◽

Passing Rate ◽

Beam Delivery ◽

Gamma Passing Rate ◽

Dynamic Wave

Abstract Background: Dose reduction to the duodenum is important to decrease gastrointestinal toxicities in patients with locally advanced pancreatic cancer (LAPC) treated with definitive chemoradiotherapy. We aimed to compare dynamic wave arc (DWA), a volumetric-modulated beam delivery technique with simultaneous gantry/ring rotations passing the waved trajectories, with coplanar VMAT (co-VMAT) with respect to dose distributions in LAPC. Methods: DWA and co-VMAT plans were created for 13 patients with LAPC in the pancreatic head or body. The prescribed dose was 45.6 or 48 Gy in 15 fractions. The dose volume indices (DVIs) for the gross tumor volume, planning target volume (PTV), stomach, duodenum, small bowel, large bowel, kidney, liver, and spinal cord were compared between the corresponding plans. The values of the gamma passing rate, monitor unit (MU), and beam-on time were also compared. Results: The volumes of the duodenum receiving 39, 42, and 45 Gy were significantly reduced to 2.8, 0.8 and 0.15 cm3 in DWA from 3.9, 1.6 and 0.34 cm3 in co-VMAT, respectively. The mean dose of the liver and D2cm3 of the planning volume for the spinal cord were significantly increased to 6.9 and 31.7 Gy in DWA from 5.9 and 30.2 Gy in co-VMAT, respectively. Meanwhile, there was no significant difference in the target volumes except for dose irradiated to 2% of PTV (110.4% in DWA vs. 109.6% in co-VMAT). There were also no significant differences in the other DVIs. Further, the gamma passing rate was 96.5% for DWA and 96.7% for co-VMAT (p = 0.65). The MU was significantly higher in DWA than in co-VMAT (620 vs. 589, p = 0.001), and there was a significant increase in the beam-on time (104 sec vs. 89 sec, p = 0.04).Conclusion: DWA was superior to co-VMAT regarding dose distributions in the duodenum in LAPC, albeit with slight increasing doses to the liver and the spinal cord and increasing MU and the beam delivery time. Further evaluation is needed to know how the dose differences would affect the clinical outcomes in chemoradiotherapy for LAPC.

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What is plan quality in radiotherapy? The importance of evaluating dose metrics, complexity, and robustness of treatment plans

Radiotherapy and Oncology ◽

10.1016/j.radonc.2020.09.038 ◽

2020 ◽

Vol 153 ◽

pp. 26-33 ◽

Cited By ~ 2

Author(s):

Victor Hernandez ◽

Christian Rønn Hansen ◽

Lamberto Widesott ◽

Anna Bäck ◽

Richard Canters ◽

...

Keyword(s):

Plan Quality ◽

Dose Metrics ◽

Treatment Plans

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Multicriterial CNN based beam generation for robotic radiosurgery of the prostate

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2020-0030 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Stefan Gerlach ◽

Christoph Fürweger ◽

Theresa Hofmann ◽

Alexander Schlaefer

Keyword(s):

Deep Learning ◽

Treatment Planning ◽

Treatment Plan ◽

Plan Quality ◽

New Approach ◽

Beam Generation ◽

Radiological Features ◽

Improve Treatment ◽

Robotic Radiosurgery ◽

Treatment Plans

AbstractAlthough robotic radiosurgery offers a flexible arrangement of treatment beams, generating treatment plans is computationally challenging and a time consuming process for the planner. Furthermore, different clinical goals have to be considered during planning and generally different sets of beams correspond to different clinical goals. Typically, candidate beams sampled from a randomized heuristic form the basis for treatment planning. We propose a new approach to generate candidate beams based on deep learning using radiological features as well as the desired constraints. We demonstrate that candidate beams generated for specific clinical goals can improve treatment plan quality. Furthermore, we compare two approaches to include information about constraints in the prediction. Our results show that CNN generated beams can improve treatment plan quality for different clinical goals, increasing coverage from 91.2 to 96.8% for 3,000 candidate beams on average. When including the clinical goal in the training, coverage is improved by 1.1% points.

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PO-1039 Spine SBRT with Halcyon™: Plan Quality, Delivery Accuracy, and Speed

Radiotherapy and Oncology ◽

10.1016/s0167-8140(19)31459-8 ◽

2019 ◽

Vol 133 ◽

pp. S577-S578

Author(s):

H. Petroccia ◽

I. Malajovich ◽

C. Wang ◽

K. Teo ◽

D. Lei ◽

...

Keyword(s):

Plan Quality ◽

Delivery Accuracy

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Interstitial High Dose Rate (HDR) Brachytherapy for Early Stage Breast Cancer: A Report of 136 Cases

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2007.07.1213 ◽

2007 ◽

Vol 69 (3) ◽

pp. S229 ◽

Cited By ~ 2

Author(s):

P.J. Anderson ◽

R.J. Mark ◽

R.S. Akins ◽

T.R. Neumann ◽

S. Gurley ◽

...

Keyword(s):

Breast Cancer ◽

Dose Rate ◽

Early Stage ◽

High Dose Rate ◽

Early Stage Breast Cancer ◽

High Dose ◽

Hdr Brachytherapy

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Designing Personalized Treatment Plans for Breast Cancer

Information Systems Research ◽

10.1287/isre.2021.1002 ◽

2021 ◽

Author(s):

Wei Chen ◽

Yixin Lu ◽

Liangfei Qiu ◽

Subodha Kumar

Keyword(s):

Breast Cancer ◽

Domain Knowledge ◽

Early Stage ◽

Radiotherapy Planning ◽

Breast Cancer Patients ◽

Support Tools ◽

Treatment Plans ◽

Radiation Induced ◽

Effective Decision ◽

Effective Decision Support

Breast cancer remains the leading cause of cancer deaths among women around the world. Contemporary treatment for breast cancer is complex and involves highly specialized medical professionals collaborating in a series of information-intensive processes. This poses significant challenges to optimization of treatment plans for individual patients. We propose a novel framework that enables personalization and customization of treatment plans for early stage breast cancer patients undergoing radiotherapy. Using a series of simulation experiments benchmarked with real-world clinical data, we demonstrate that the treatment plans generated from our proposed framework consistently outperform those from the existing practices in balancing the risk of local tumor recurrence and radiation-induced adverse effects. Our research sheds new light on how to combine domain knowledge and patient data in developing effective decision-support tools for clinical use. Although our research is specifically geared toward radiotherapy planning for breast cancer, the design principles of our framework can be applied to the personalization of treatment plans for patients with other chronic diseases that typically involve complications and comorbidities.

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