Diagnosis and Planning in Orthognathic Surgery

AbstractThe clinical evaluation of the face is the most important aspect of evaluating patients with dentofacial deformities. The clinical examination is the primary determinant in making a diagnosis and developing a treatment plan. The basic treatment goals are: establishment of orofacial function, ensure stability of results, achieve facial esthetics and to consider the patency of the airway. The systematic clinical examination is divided into five basic evaluations: the frontal view, the profile view, three quarter view, an occlusal assessment and the temporomandibular joint evaluation. The clinical diagnosis is then confirmed with special investigations such as panoramic, lateral and anteroposterior cephalometric radiographs and other investigations as required. A dental, skeletal and soft tissue problem list is then noted and orthodontic and surgical solutions integrated into a final treatment plan. A cephalometric radiographic tracing or a 3D virtual treatment planning system is finally used to measure the planned surgical movements and to visualize the expected treatment results.

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An Integrated Framework Based on Full Monte Carlo Simulations for Double-Scattering Proton Therapy

International Journal of Particle Therapy ◽

10.14338/ijpt-19-00063.1 ◽

2019 ◽

Vol 6 (2) ◽

pp. 31-41

Author(s):

Jiankui Yuan ◽

David Mansur ◽

Min Yao ◽

Tithi Biswas ◽

Yiran Zheng ◽

...

Keyword(s):

Monte Carlo ◽

Proton Therapy ◽

Treatment Plan ◽

Planning System ◽

Treatment Planning System ◽

Patient Specific ◽

Double Scattering ◽

Integrated Framework ◽

End To End ◽

Clinical Cases

ABSTRACT Purpose: We developed an integrated framework that employs a full Monte Carlo (MC) model for treatment-plan simulations of a passive double-scattering proton system. Materials and Methods: We have previously validated a virtual machine source model for full MC proton-dose calculations by comparing the percentage of depth-dose curves, spread-out Bragg peaks, and lateral profiles against measured commissioning data. This study further expanded our previous work by developing an integrate framework that facilitates its clinical use. Specifically, we have (1) constructed patient-specific applicator and compensator numerically from the plan data and incorporated them into the beamline, (2) created the patient anatomy from the computed tomography image and established the transformation between patient and machine coordinate systems, and (3) developed a graphical user interface to ease the whole process from importing the treatment plan in the Digital Imaging and Communications in Medicine format to parallelization of the MC calculations. End-to-end tests were performed to validate the functionality, and 3 clinical cases were used to demonstrate clinical utility of the framework. Results: The end-to-end tests demonstrated that the framework functioned correctly for all tested functionality. Comparisons between the treatment planning system calculations and MC results in 3 clinical cases revealed large dose difference up to 17%, especially in the beam penumbra and near the end of beam range. The discrepancy likely originates from a variety of sources, such as the dose algorithms, modeling of the beamline, and the dose metric. The agreement for other regions was acceptable. Conclusion: An integrated framework was developed for full MC simulations of double-scattering proton therapy. It can be a valuable tool for dose verification and plan evaluation.

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A hybrid approach for head and neck cancer using online image guidance and offline adaptive radiotherapy planning

Journal of Radiotherapy in Practice ◽

10.1017/s146039691800078x ◽

2019 ◽

Vol 18 (03) ◽

pp. 271-275 ◽

Cited By ~ 1

Author(s):

Roopam Srivastava ◽

P.K. Sharma ◽

K.J. Maria Das ◽

Jayanand Manjhi

Keyword(s):

Computed Tomography ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Dose Distribution ◽

Treatment Plan ◽

Planning System ◽

Radiotherapy Planning ◽

Treatment Planning System ◽

Medical Systems

AbstractBackgroundThis is a prospective study to evaluate the dosimetric benefits of treatment plan adaptation for patients who had undergone repeat computed tomography (ReCT)and re-planning due to treatment-induced anatomical changes during radiotherapy.Materials and MethodsThis study involved five head and neck cancer patients who had their treatment plan modified, based on weekly thrice imaging protocol. Impact of mid-course imaging was assessed in patients using ReCT and cone beam computed tomography (CBCT)-based dose verification. Patients were imaged, apart from their initial CT, during the course of their radiation therapy with a ReCT and on board imager CBCT (Varian Medical Systems Inc., Palo Alto, CA, USA). Each CBCT/CT series was rigidly registered to the initial CT in the treatment planning system Eclipse (Varian Medical Systems Inc.) using bony landmarks. The structures were copied to the current CBCT/CT series and, where needed, manually edited slicewise. The dose distribution from the treatment plan was viewed as of the current anatomy by applying the treatment plan the CBCT/CT series, and studying the corresponding dose–volume histograms for organs at risk doses.ResultsThe reduction of parotid volumes due to weight loss was observed in all patients, which means an increase in predicted mean doses of parotid when initial CT plan was re-calculated on ReCT and CBCT (Table 1). This explains the necessity of adaptive planning. The predicted mean dose of parotid glands was increased and constraints to spinal cord and skin were exceeded, so re-planning was performed.ConclusionsThe CBCT is a useful tool to view anatomic changes in patients and get an estimate of their impact on dose distribution. Re-planning based on imaging in head and neck patients during the course of radiotherapy is mandatory to reduce side effects.

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Utilising virtual bolus in superficial planning target volume dose optimisation (TomoTherapy): a phantom study

Journal of Radiotherapy in Practice ◽

10.1017/s1460396919000438 ◽

2019 ◽

Vol 19 (1) ◽

pp. 65-70

Author(s):

Gim Chee Ooi ◽

Iskandar Shahrim Bin Mustafa

Keyword(s):

Treatment Planning ◽

Planning Target Volume ◽

Treatment Plan ◽

Target Volume ◽

The Body ◽

Phantom Study ◽

Planning System ◽

Treatment Planning System ◽

Dose Volume Histograms ◽

Photon Fluence

AbstractAim:This is a phantom study to evaluate the dosimetry effects of using virtual bolus (VB) in TomoTherapy Treatment Planning System (TPS) optimisation for superficial planning target volume (PTV) that extends to the body surface. Without VB, the inverse-planning TPS will continuously boost the photon fluence at the surface of the superficial PTV due to lack of build-up region. VB is used during TPS optimisation only and will not be present in actual treatment delivery.Materials and methods:In this study, a dummy planning target was contoured on a cylindrical phantom which extends to the phantom surface, and VB of various combinations of thickness and density was used in treatment planning optimisation with TomoTherapy TPS. The plans were then delivered with the treatment modality TomoTherapy. Radiochromic films (Gafchromic EBT3) were calibrated and used for dose profiles measurements. TomoTherapy Planned-Adaptive software was used to analyse the delivered Dose-Volume Histograms (DVHs).Results:The use of 2 mm VB was not providing adequate build-up area and was unable to reduce the hot spots during treatment planning and actual delivery. The use of 4 mm VB was able to negate the photon fluence boosting effect by the TPS, and the actual delivery showed relatively small deviations from the treatment plan. The use of 6 mm VB caused significant dose overestimation by the TPS in the superficial regions resulting in insufficient dose coverage delivered.Findings:VB with the combination of 4 mm thickness and 1·0 g/cc density provides the most robust solution for the TomoTherapy TPS optimisation of superficial PTV.

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CLINICAL IMPLEMENTATION OF RADIOBIOLOGICAL TREATMENT PLAN OPTIMIZATION USING A DATABASE AND CALCULATION MODULE INTEGRATED TO A TREATMENT PLANNING SYSTEM

Radiotherapy and Oncology ◽

10.1016/s0167-8140(12)73232-2 ◽

2009 ◽

Vol 92 ◽

pp. S239

Author(s):

A. Tzikas ◽

P. Mavroidis ◽

N. Papanikolaou ◽

S. Stathakis ◽

B. Lind

Keyword(s):

Treatment Planning ◽

Treatment Plan ◽

Planning System ◽

Treatment Planning System ◽

Clinical Implementation ◽

Plan Optimization ◽

Treatment Plan Optimization ◽

Calculation Module

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Evaluating the Effect of the Silicone Prosthesis on the Photon Dose Distribution in Radiation Therapy of Breast Cancer

Frontiers in Biomedical Technologies ◽

10.18502/fbt.v8i3.7112 ◽

2021 ◽

Author(s):

Shaghayegh Olfat ◽

Payam Samadi Miandoab ◽

Nooshin Banaee

Keyword(s):

Breast Cancer ◽

Soft Tissue ◽

Electron Density ◽

Dose Distribution ◽

Treatment Plan ◽

Planning System ◽

Treatment Planning System ◽

Tissue Water ◽

Air Cavity ◽

Silicone Prosthesis

Purpose: Breast cancer is the most common malignancy among women which in some cases is followed by breast reconstructions. The objective of the experimental study is to investigate the effect of the silicone prosthesis implementation on the dose distribution of radiotherapy. Materials and Methods: Initially CT images of 7 mastectomy breast patients with silicone prosthesis were imported to the Monaco treatment planning system. A treatment plan consisting of two tangential photon fields with a prescription dose of 50Gy was arranged. To study the effect and water equivalency of silicone prosthesis, dose distribution of treatment plan was acquired in two conditions: 1) considering the real electron density of silicone prosthesis; 2) modifying (Relative electron density) RED of silicone prosthesis to 1 to virtually assume it as soft tissue (water). The results were then compared by VeriSoft software to evaluate the gamma index. Results: The obtained results indicated that the RED for the silicon prosthesis varies between 0.7 and 1.14 while the RED for soft tissue is approximately 1. Also, the Dose-volume histogram curves for both conditions indicated that the minimum and maximum differences ranged from 1% to 4%. The significant differences might be due to the presence of the air cavity or bubbles in the silicone prosthesis implementation or air voxels between prostheses and soft tissue. Conclusion: The obtained results showed that if there is no air cavity in silicone prosthesis and the surgery is performed in a way that no volume of air is left between the prosthesis and breast tissue, the effect and presence of silicone prosthesis will be similar to soft tissue (water).

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A Treatment Planning System for the Small Animal Radiation Research Platform (SARRP) based on 3D Slicer

10.54294/hsb0g8 ◽

2012 ◽

Author(s):

Nathan Cho ◽

Peter Kazanzides

Keyword(s):

Treatment Planning ◽

High Performance ◽

Treatment Plan ◽

Small Animal ◽

Planning System ◽

Treatment Planning System ◽

3D Slicer ◽

Research Platform ◽

Typical Treatment ◽

Radiation Research

This paper describes the software integration of a treatment planning system (TPS), based on the open-source 3D Slicer package, with the Small Animal Radiation Research Platform (SARRP).The TPS is designed to enable researchers to replicate their clinical techniques, allow for image fusion with other imaging modalities, and provide dose computation and graphical visualization of treatment plans consisting of multiple x-ray beams and conformable arcs. The dose computation is implemented on a GPU to achieve high performance; the dose volume for a typical treatment plan can be computed in less than a minute.

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Evaluation of Delta4DVH Anatomy in 3D Patient-Specific IMRT Quality Assurance

Technology in Cancer Research & Treatment ◽

10.1177/1533033820945816 ◽

2020 ◽

Vol 19 ◽

pp. 153303382094581

Author(s):

Du Tang ◽

Zhen Yang ◽

Xunzhang Dai ◽

Ying Cao

Keyword(s):

Quality Assurance ◽

Treatment Planning ◽

Treatment Plan ◽

Planning System ◽

Treatment Planning System ◽

Patient Specific ◽

Pencil Beam ◽

Ion Chamber ◽

Passing Rate ◽

Gamma Passing Rate

Purpose: To evaluate the performance of Delta4DVH Anatomy in patient-specific intensity-modulated radiotherapy quality assurance. Materials and Methods: Dose comparisons were performed between Anatomy doses calculated with treatment plan dose measured modification and pencil beam algorithms, treatment planning system doses, film doses, and ion chamber measured doses in homogeneous and inhomogeneous geometries. The sensitivity of Anatomy doses to machine errors and output calibration errors was also investigated. Results: For a Volumetric Modulated Arc Therapy (VMAT) plan evaluated on the Delta4 geometry, the conventional gamma passing rate was 99.6%. For a water-equivalent slab geometry, good agreements were found between dose profiles in film, treatment planning system, and Anatomy treatment plan dose measured modification and pencil beam calculations. Gamma passing rate for Anatomy treatment plan dose measured modification and pencil beam doses versus treatment planning system doses was 100%. However, gamma passing rate dropped to 97.2% and 96% for treatment plan dose measured modification and pencil beam calculations in inhomogeneous head & neck phantom, respectively. For the 10 patients’ quality assurance plans, good agreements were found between ion chamber measured doses and the planned ones (deviation: 0.09% ± 1.17%). The averaged gamma passing rate for conventional and Anatomy treatment plan dose measured modification and pencil beam gamma analyses in Delta4 geometry was 99.6% ± 0.89%, 98.54% ± 1.60%, and 98.95% ± 1.27%, respectively, higher than averaged gamma passing rate of 97.75% ± 1.23% and 93.04% ± 2.69% for treatment plan dose measured modification and pencil beam in patients’ geometries, respectively. Anatomy treatment plan dose measured modification dose profiles agreed well with those in treatment planning system for both Delta4 and patients’ geometries, while pencil beam doses demonstrated substantial disagreement in patients’ geometries when compared to treatment planning system doses. Both treatment planning system doses are sensitive to multileaf collimator and monitor unit (MU) errors for high and medium dose metrics but not sensitive to the gantry and collimator rotation error smaller than 3°. Conclusions: The new Delta4DVH Anatomy with treatment plan dose measured modification algorithm is a useful tool for the anatomy-based patient-specific quality assurance. Cautions should be taken when using pencil beam algorithm due to its limitations in handling heterogeneity and in high-dose gradient regions.

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Beam complexity and monitor unit efficiency comparison in two different volumetric modulated arc therapy delivery using automated planning

10.21203/rs.3.rs-23401/v1 ◽

2020 ◽

Author(s):

Chengqiang Li ◽

Cheng Tao ◽

Tong Bai ◽

Zhenjiang Li ◽

Ying Tong ◽

...

Keyword(s):

Treatment Plan ◽

Volumetric Modulated Arc Therapy ◽

Delivery Systems ◽

Planning System ◽

Treatment Planning System ◽

Monitor Unit ◽

Plan Quality ◽

Arc Therapy ◽

Efficiency Comparison ◽

Beam Complexity

Abstract Background: To investigate the beam complexity and monitor unit（MU）efficiency issues for two different volumetric modulated arc therapy (VMAT) delivery technologies for patients with left-sided breast cancer (BC) and nasopharyngeal carcinoma (NPC). Methods: Twelve left-sided BC and seven NPC cases were enrolled in this study. Each delivered treatment plan was optimized in Pinnacle 3 treatment planning system with Auto-Planning module for Trilogy and Synergy systems. Similar planning dose objectives and beam configuration were used for each site in two different delivery systems to produce clinically acceptable plans. Beam complexity was evaluated in terms of segment area(SA), segment width(SW), leaf sequence variability(LSV), aperture area variability(AAV), modulation complexity score(MCS) based on MLC sequence and MU. Results: With similar plan quality, the average SAs for Trilogy plans were smaller than those for Synergy plans: 55.5 ± 21.3 cm 2 vs. 66.3 ± 17.9 cm 2 (p<0.05) for the NPC cases, and 100.7 ± 49.2 cm 2 vs. 108.5 ± 42.7 cm 2 (p<0.05) for BC cases, respectively. The SW was statistically significant for two delivery systems (NPC: 6.87±1.95cm vs.6.72±2.71cm, p < 0.05; BC: 8.84±2.56cm vs.8.09±2.63cm, p < 0.05). LSV was statistically significant smaller for Trilogy (NPC: 0.84±0.033 vs.0.86±0.033, p < 0.05; BC: 0.89±0.026 vs.0.90±0.26, p < 0.05). The mean AAV was statistically significant larger for Trilogy than Synergy (NPC: 0.18±0.064 vs.0.14±0.037, p < 0.05; BC: 0.46±0.15 vs.0.33±0.13, p < 0.05). The MCS values for the Trilogy were higher than those for the Synergy: 0.14 ± 0.016vs. 0.12 ± 0.017 (p<0.05) for the NPC cases, and 0.42 ± 0.106 vs. 0.30 ± 0.087(p<0.05) for the BC cases. Compared with Synergy plans, the average MU for Trilogy plans were larger: 828.6±74.1MU and 782.9±85.2MU (p>0.05) for the NPC cases, and 444.8±61.3MU and 393.8±75.3MU (p>0.05) for the BC cases. Conclusions: The pinnacle 3 Auto planning system can optimize BC and NPC plans to obtain the same plan quality using Trilogy and Synergy systems. We found that this two systems resulted in different SA, SW, LSV, AAV and MCS. As a result, we suggested that beam complexity should be considered in providing further methodologies while optimizing VMAT auto planning.

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Efficacy of Panoramic Radiography in Dental Diagnosis and Treatment Planning

Journal of Dental Research ◽

10.1177/00220345890680051101 ◽

1989 ◽

Vol 68 (5) ◽

pp. 810-812 ◽

Cited By ~ 10

Author(s):

M.L. Kantor ◽

B.A. Slome

Keyword(s):

Clinical Examination ◽

Panoramic Radiography ◽

Diagnostic Yield ◽

Treatment Plan ◽

Panoramic Radiograph ◽

Diagnostic Assessment ◽

Final Treatment ◽

Treatment Plans ◽

Diagnostic Work ◽

Work Up

We compared treatment decisions based on a clinical examination alone with decisions based on an examination plus a panoramic radiograph to determine whether the panoramic radiograph increased the diagnostic yield and consequently affected treatment. Provisional treatment plans, based on a screening clinical examination alone (n = 33), or on a screening clinical examination plus panoramic radiograph (n = 43), were compared with final treatment plans based on a complete diagnostic assessment (including all necessary radiographs). For this analysis, the final treatment plan was considered correct and used as the gold standard. The two groups used in the comparison were equivalent in age, gender, and final treatment plan needs. The availability of a panoramic radiograph did not improve the accuracy with which provisional treatment plans predicted the number of teeth requiring composites, amalgams, crowns, or extraction, nor did it improve the accuracy of the assessment of the periodontal status (Wilcoxon rank sum, alpha = 0.05). The proportion of patients who had an intra-oral full-mouth series as part of the complete diagnostic work-up was essentially the same for both groups (58% and 60%, respectively); the availability of the panoramic film did not reduce the need for full-mouth series radiographs for the development of the final treatment plans.

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