scholarly journals Delivery, Beam and Range Monitoring in Particle Therapy in a Highly Innovative Integrated Design

2020 ◽  
Vol 8 ◽  
Author(s):  
L. Bottura ◽  
E. Felcini ◽  
V. Ferrero ◽  
E. Fiorina ◽  
V. Monaco ◽  
...  
Keyword(s):  
Treatment Plan ◽  
Integrated Design ◽  
Cost Effective ◽  
Target Volume ◽  
Particle Therapy ◽  
Treatment Delivery ◽  
Expected Performance ◽  
Beam Delivery ◽  
Technological Improvements ◽  
System Prototype

The design of a particle therapy system that integrates an innovative beam delivery concept based on a static toroidal gantry and an imaging configuration suitable for beam and online range monitoring is proposed and discussed. Such approach would provide a compact and cost-effective layout, with a highly flexible and fast beam delivery, single particle counting capability for fast measurement of beam fluence and position and a precise real time verification of the compliance between the treatment delivery and its prescription. The gantry configuration is discussed, presenting an analysis of the residual magnetic field in the bore and of the feasibility of irradiating a realistic target volume. Moreover, the expected performance of the PET-based range monitor is assessed through Monte Carlo simulations, showing a precision in the reconstruction of the activity distribution from a clinical treatment plan better than the state-of-the-art devices. The feasibility of the proposed design is then discussed through an assessment of the technological improvements required to actually start the construction and commissioning of a system prototype.

scholarly journals Nanodosimetry-Based Plan Optimization for Particle Therapy

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Margherita Casiraghi ◽  
Reinhard W. Schulte
Keyword(s):  
Treatment Plan ◽  
Target Volume ◽  
Particle Therapy ◽  
Optimization Strategy ◽  
Plan Optimization ◽  
Treatment Plan Optimization ◽  
Treatment Plans ◽  
Mixed Field ◽  
Single Field ◽  
Mixed Radiation Field

Treatment planning for particle therapy is currently an active field of research due uncertainty in how to modify physical dose in order to create a uniform biological dose response in the target. A novel treatment plan optimization strategy based on measurable nanodosimetric quantities rather than biophysical models is proposed in this work. Simplified proton and carbon treatment plans were simulated in a water phantom to investigate the optimization feasibility. Track structures of the mixed radiation field produced at different depths in the target volume were simulated with Geant4-DNA and nanodosimetric descriptors were calculated. The fluences of the treatment field pencil beams were optimized in order to create a mixed field with equal nanodosimetric descriptors at each of the multiple positions in spread-out particle Bragg peaks. For both proton and carbon ion plans, a uniform spatial distribution of nanodosimetric descriptors could be obtained by optimizing opposing-field but not single-field plans. The results obtained indicate that uniform nanodosimetrically weighted plans, which may also be radiobiologically uniform, can be obtained with this approach. Future investigations need to demonstrate that this approach is also feasible for more complicated beam arrangements and that it leads to biologically uniform response in tumor cells and tissues.

scholarly journals Improved robustness in the junction region for postoperative breast cancer including supraclavicular nodes using hybrid VMAT

2021 ◽  
Author(s):  
Hideharu Miura ◽  
Yoshiko Doi ◽  
Minoru Nakao ◽  
Shuichi Ozawa ◽  
Masahiko Kenjo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Low Dose ◽  
Treatment Plan ◽  
Target Volume ◽  
Breast Cancer Patients ◽  
Junction Region ◽  
Treatment Delivery ◽  
Patient Motion ◽  
3D Crt

Abstract Purpose To improve the hybrid VMAT treatment plan robustness for postoperative breast cancer patients considering small patient motion shifts during treatment using a 3D-CRT with a dose gradient in the junction region. Methods Locoregional supraclavicular nodes of breast cancer patients were planned using 3D-CRT and VMAT. A 3D-CRT plan with a dose gradient on the cranial side was applied by shifting the jaw to reduce hot or cold spots. The VMAT plan was optimized based on the results of the 3D-CRT plan calculation. Hybrid plans were created by the sum of the 3D-CRT and VMAT plans. To simulate patient motion, the plans were recalculated with the VMAT plan simulating isocenter superiorly (separation) or inferiorly (overlap) shifted by 1, 2, and 3 mm. The shifted plans were compared with the non-shifted plans considering the clinical target volume (CTV) (D98% or D2%). Results The D2% value of the CTV with perfectly aligned fields for the hybrid VMAT plan with high- or low-dose gradients on the 3D-CRT plan increased from 102.8%/102.9–107.2%/105.7%, 114.9%/110.9%, and 122.2%/115.5% for each 1 mm, 2 mm, and 3 mm overlapped shift, respectively. The value of D98% to the CTV with perfectly aligned fields decreased from 95.7%/95.6–90.0%/93.1%, 81.2%/88.4%, and 72.8%/83.5% for each 1 mm, 2 mm, and 3 mm separated shift, respectively. Conclusions By employing a 3D-CRT plan with a low dose gradient on the cranial side, the dose differences can be decreased. A more robust treatment delivery option can be achieved for breast cancer treatment using our proposed hybrid VMAT.

scholarly journals Dosimetric comparison of MR-linac-based IMRT and conventional VMAT treatment plans for prostate cancer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Vanessa Da Silva Mendes ◽  
Lukas Nierer ◽  
Minglun Li ◽  
Stefanie Corradini ◽  
Michael Reiner ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Target Coverage ◽  
Treatment Delivery ◽  
Ptv Margin ◽  
Delivery Times ◽  
Low Field ◽  
Treatment Plans

Abstract Background The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were estimated, by creating IMRT MRL plans using smaller PTV margins. Materials and methods 20 PCa patients previously treated with conventional VMAT were considered. For each patient, two different IMRT MRL plans using the low-field MR-linac treatment planning system were created: one with original (orig.) PTV margins and the other with reduced (red.) PTV margins. Dose indices related to target coverage, as well as dose-volume histogram (DVH) parameters for the target and organs at risk (OAR) were compared. Additionally, the estimated treatment delivery times and the number of monitor units (MU) of each plan were evaluated. Results The dose distribution in the high dose region and the target volume DVH parameters (D98%, D50%, D2% and V95%) were similar for all three types of treatment plans, with deviations below 1% in most cases. Both IMRT MRL plans (orig. and red. PTV margins) showed similar homogeneity indices (HI), however worse values for the conformity index (CI) were also found when compared to VMAT. The IMRT MRL plans showed similar OAR sparing when the orig. PTV margins were used but a significantly better sparing was feasible when red. PTV margins were applied. Higher number of MU and longer predicted treatment delivery times were seen for both IMRT MRL plans. Conclusions A comparable plan quality between VMAT and IMRT MRL plans was achieved, when applying the same PTV margin. However, online MR-guided adaptive radiotherapy allows for a reduction of PTV margins. With a red. PTV margin, better sparing of the surrounding tissues can be achieved, while maintaining adequate target coverage. Nonetheless, longer treatment delivery times, characteristic for the IMRT technique, have to be expected.

scholarly journals A novel index for assessing treatment plan quality in stereotactic radiosurgery

2018 ◽  
Vol 129 (Suppl1) ◽  
pp. 118-124 ◽  
Author(s):  
Alexis Dimitriadis ◽  
Ian Paddick
Keyword(s):  
Stereotactic Radiosurgery ◽  
Treatment Plan ◽  
Efficiency Index ◽  
Target Volume ◽  
Surrounding Tissue ◽  
Plan Quality ◽  
Multiple Target ◽  
Integral Dose ◽  
Plan Optimization ◽  
Dose Volume

OBJECTIVEStereotactic radiosurgery (SRS) is characterized by high levels of conformity and steep dose gradients from the periphery of the target to surrounding tissue. Clinical studies have backed up the importance of these factors through evidence of symptomatic complications. Available data suggest that there are threshold doses above which the risk of symptomatic radionecrosis increases with the volume irradiated. Therefore, radiosurgical treatment plans should be optimized by minimizing dose to the surrounding tissue while maximizing dose to the target volume. Several metrics have been proposed to quantify radiosurgical plan quality, but all present certain weaknesses. To overcome limitations of the currently used metrics, a novel metric is proposed, the efficiency index (η50%), which is based on the principle of calculating integral doses: η50% = integral doseTV/integral dosePIV50%.METHODSThe value of η50% can be easily calculated by dividing the integral dose (mean dose × volume) to the target volume (TV) by the integral dose to the volume of 50% of the prescription isodose (PIV50%). Alternatively, differential dose-volume histograms (DVHs) of the TV and PIV50% can be used. The resulting η50% value is effectively the proportion of energy within the PIV50% that falls into the target. This value has theoretical limits of 0 and 1, with 1 being perfect. The index combines conformity, gradient, and mean dose to the target into a single value. The value of η50% was retrospectively calculated for 100 clinical SRS plans.RESULTSThe value of η50% for the 100 clinical SRS plans ranged from 37.7% to 58.0% with a mean value of 49.0%. This study also showed that the same principles used for the calculation of η50% can be adapted to produce an index suitable for multiple-target plans (Gη12Gy). Furthermore, the authors present another adaptation of the index that may play a role in plan optimization by calculating and minimizing the proportion of energy delivered to surrounding organs at risk (OARη50%).CONCLUSIONSThe proposed efficiency index is a novel approach in quantifying plan quality by combining conformity, gradient, and mean dose into a single value. It quantifies the ratio of the dose “doing good” versus the dose “doing harm,” and its adaptations can be used for multiple-target plan optimization and OAR sparing.

scholarly journals AN INTEGRATED DESIGN METHODOLOGY

2011 ◽  
Author(s):  
T. Freiheit ◽  
S. S. Park ◽  
V Giuliani
Keyword(s):  
Design Methodology ◽  
Integrated Design ◽  
Cost Effective ◽  
Global Markets ◽  
Design Tools ◽  
Regulatory Requirements ◽  
Life Cycle Design ◽  
Design Requirements ◽  
Stakeholder Needs ◽  
Integrated Design Methodology

Global markets demand quick product develop-ment that is simultaneously cost-effective and meets stakeholder needs. Many tools and design methodolo-gies have been developed that address individual as-pects of the design problem, such as Axiomatic De-sign, Design for Manufacture, Life Cycle Design, etc. However, competitive viability can be put at risk when a product fails to achieve all customer, business, manufacturing, and regulatory requirements. To de-liver all design requirements, an efficient integrated design methodology is required. This paper proposes a design approach which integrates previously devel-oped design tools to economically achieve essential design objectives, within a framework that facilitates a rapid design process.

scholarly journals Detachable Lip and Cheek Plumper for Rehabilitation of Facial Disfigurement

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Nada Fathalla Abdelbagi ◽  
Ibrahim Ahmed Ismail ◽  
Fadia Awadalkreem ◽  
Mohammed Nasser Alhajj
Keyword(s):  
Social Life ◽  
Alveolar Bone ◽  
Treatment Plan ◽  
Young Male ◽  
Cost Effective ◽  
Surgical Removal ◽  
Individual Character ◽  
Swallowing Difficulties ◽  
Oroantral Communication ◽  
And Function

Background. Hemimaxillectomy of acquired palatal defects may predispose the patient to hypernasal speech, leakage of fluids into the nasal cavity, impaired masticatory function, and swallowing difficulties leading to a detrimental impact on the quality of life. Sequentially, it can also affect individual character and trust in social life, leading to social phobia and anxiety. This article presents prosthodontic management of a young male patient with deformation of the entire right half of the face due to surgical removal of odontogenic myxoma. It describes a method where the clinician utilized a simple, noninvasive, and cost-effective technique to cut the weight of the obturator and to attain aesthetics, utilizing a detachable lip and cheek plumper. Case Presentation. A 19-year-old male attended the Prosthodontic Clinics at Faculty of Dentistry, the University of Khartoum, eight months after the surgical removal of a tumor. The chief complaint was difficulty eating or drinking. Furthermore, he dropped out of school because of his facial deformity and his indistinct voice. Medical and dental history revealed surgical resection of the entire right half of the maxillary alveolar bone due to myxoma. Intraoral examination revealed a well-healed surgical defect in the maxillary right buccal vestibule creating an oroantral communication. A treatment plan was formulated, keeping the patient’s demand in mind. The decision was made to treat the patient with a maxillary obturator that would gain its support from the remaining teeth and tissues with a detachable cheek and lip plumper. The use of dental magnets as a means of attachment was elected. Conclusion. This article has described a simple, noninvasive, and cost-effective method to improve facial appearance in patients with hollow faces. The plumper prosthesis successfully improved the patient’s appearance to the extent that comfort and function would permit and encourage self-esteem.

Abstract T P276: Transient Ischemic Attack Clinic Drives Superior Patient Outcomes While Reducing Cost

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Jim Woodard ◽  
Shelby Haschker
Keyword(s):  
Average Cost ◽  
Treatment Plan ◽  
Cost Effective ◽  
Clinic Visit ◽  
Fiscal Year ◽  
Time Interval ◽  
Short Time Interval ◽  
Emergency Rooms ◽  
High Satisfaction ◽  
Ischemic Attack

It is estimated that 40% of all individuals that experience a TIA will ultimately suffer a stroke. As many as 50% of these patients will have a stroke within one week post TIA. Given the short time interval between TIA symptomology and stroke onset, immediate treatment is warranted. Historically treatment of TIA patients has taken place in emergency rooms and as hospital inpatients. A TIA clinic was established in 2011 as an alternative option to traditional TIA treatment. This clinic was designed to expedite diagnosis and treatment while reducing cost. Utilizing the ABCD2 tool, emergency department clinicians, PCPs and ophthalmologists referred low risk patients to the clinic. Clinic patients were scheduled to be seen in the clinic within 24-48 hours. All testing, stroke/TIA education, neurological consultation and secondary treatment plan were completed during the clinic visit. To date, the clinic has evaluated 137 patients. There have been no reports of stroke 90-days post clinic visit. Stroke rates post TIA are estimated to be as high as 17% after 3 months. This data supports the TIA clinic’s success in secondary stroke prevention. Patients seen in the clinic reported high satisfaction scores with the clinic and the care they received. It was initially hypothesized that the TIA clinic would provide care in a more cost effective way. A cost analysis was performed comparing TIA clinic costs and the cost of treating patients admitted to the hospital. Using fiscal year 2014 data, the average cost for treating a patient in the clinic was $423. The average cost for admitting a patient to the hospital was $1,464 per patient. The TIA clinic has shown that patients can receive timely treatment in a setting that produces the highest clinical outcomes, maintains patient satisfaction and reduces cost by 70%.

scholarly journals Impact of 4D CT for treatment planning of moving targets: a computer-based biological evaluation

2017 ◽  
Vol 3 (2) ◽  
pp. 665-668
Author(s):  
Eike Helf ◽  
Oliver Waletzko ◽  
Christian Mehrens ◽  
Ralf Rohn ◽  
Andreas Block
Keyword(s):  
Treatment Plan ◽  
Tumour Volume ◽  
Target Volume ◽  
Biological Evaluation ◽  
Internal Target Volume ◽  
4D Ct ◽  
Tumour Control ◽  
Ct Data ◽  
Conventional Ct ◽  
The Impact

AbstractThis study deals with comparison of conventional and 4D CT (GE Lightspeed) planning on the tumour control probability (TCP), using the TCP model of the AAPM-Report Task Group 166. In the first step a VMAT treatment plan was calculated (Varian Eclipse 13.7) on basis of conventional CT data. This treatment plan was transferred to the complete 4D CT, which represents the tumour volume in motion. Due to the increased volume and the resulting decrease of tumour coverage the TCP went down from 97,6% to 91,2%. After adding an internal target volume (ITV, ICRU 62) to the conventional CT according to our clinical protocols (1,0 cm cc and 0,3 cm axial plane) the TCP increased to 98,0% when applying the conventional plan to the 4D CT. This finding demonstrates the need of 4D CT for moving tumours in chest and abdomen region.Average IPs with increasing width have been created to evaluate the impact on the TCP and the non-malignant tissue. Our observations had shown that heart, lung and spinal cord radiation exposure did not correlate to chosen respiration segment. This could be explained by the extremely slight ratio of the planning target volume and the irradiated normal tissue.This procedure enables us to evaluate the efficacy of treatment plans. Furthermore, optimizing trials like the influence of respiration-gated RT, setting individual margins and fitting planning objectives and parameters are still under investigation.

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