Dose-response modeling and treatment plan assessment with a python software toolkit.

This software assistant aims at calculating the dose-response relations of tumors and normal tissues, or clinically assessing already determined values by other researchers. It can also indicate the optimal dose prescription by optimizing the expected treatment outcome. The software is developed solely in python programming language, and it employs PSFL license for its Graphical User Interface (GUI), NUMPY, MATPLOTLIB, and SCIPY libraries.

NTCP Modeling and Dose-Volume Correlations of Significant Hematocrit Drop 3 Months After Prostate Radiation Therapy.

Purpose: Our purpose was to determine and model the dose-response relations of different parts of the pelvis regarding the endpoint of hematocrit level drop after pelvic radiation therapy (RT).

Methods And Materials: Two hundred and twenty-one patients treated with RT for prostate adenocarcinoma between 2014 and 2016 were included. All patients had complete blood counts collected at baseline and 3 months post-RT.

NTCP modelling of xerostomia after radiotherapy for oropharyngeal cancer using the PRO-CTCAE and CTCAE scoring systems at different time-points post-RT.

Purpose: This study aims at determining the parameter values of three normal tissue complication probability (NTCP) models for the contralateral parotid gland, contralateral submandibular gland (SMG) and contralateral salivary glands regarding the endpoint of xerostomia 6-24 months after radiotherapy for oropharynx cancer.

Methods: The treatment and outcome data of 231 patients with favorable risk, HPV-associated oropharyngeal squamous cell carcinoma are analyzed. 60 Gy intensity modulated radiotherapy was delivered to all the patients.

Comparison Between EPI DWI and PROPELLER DWI in Brain MR Imaging.

Objective: EPI DWI is a routinely used sequence in brain imaging but it has limitations when it comes to SNR and artifact reduction. PROPELLER DWI has the benefit of improving image quality compared to EPI DWI. The aim of this study is to compare the EPI DWI sequence in brain MR imaging with the PROPELLER DWI sequence.

Radiation-induced inferior brachial plexopathy after stereotactic body radiotherapy: Pooled analyses of risks.

Introduction: Radiation-induced brachial plexopathy (RIBP), resulting in symptomatic motor or sensory deficits of the upper extremity, is a risk after exposure of the brachial plexus to therapeutic doses of radiation. We sought to model dosimetric factors associated with risks of RIBP after stereotactic body radiotherapy (SBRT).

Methods: From a prior systematic review, 4 studies were identified that included individual patient data amenable to normal tissue complication probability (NTCP) modelling after SBRT for apical lung tumors.

Hypofractionated Stereotactic Radiation Therapy Dosimetric Tolerances for the Inferior Aspect of the Brachial Plexus: A Systematic Review.

We sought to systematically review and summarize dosimetric factors associated with radiation-induced brachial plexopathy (RIBP) after stereotactic body radiation therapy (SBRT) or hypofractionated image guided radiation therapy (HIGRT). From published studies identified from searches of PubMed and Embase databases, data quantifying risks of RIBP after 1- to 10-fraction SBRT/HIGRT were extracted and summarized. Published studies have reported <10% risks of RIBP with maximum doses (D) to the inferior aspect of the brachial plexus of 32 Gy in 5 fractions and 25 Gy in 3 fractions.

Evaluation of the clinical impact of the differences between planned and delivered dose in prostate cancer radiotherapy based on CT-on-rails IGRT and patient-reported outcome scores.

Purpose: To estimate the clinical impact of differences between delivered and planned dose using dose metrics and normal tissue complication probability (NTCP) modeling.

Methods: Forty-six consecutive patients with prostate adenocarcinoma between 2010 and 2015 treated with intensity-modulated radiation therapy (IMRT) and who had undergone computed tomography on rails imaging were included. Delivered doses to bladder and rectum were estimated using a contour-based deformable image registration method.

Stereotactic body radiotherapy optimization to reduce the risk of carotid blowout syndrome using normal tissue complication probability objectives.

Purpose: To determine the possibility of further improving clinical stereotactic body radiotherapy (SBRT) plans using normal tissue complication probability (NTCP) objectives in order to minimize the risk for carotid blowout syndrome (CBOS).

Methods: 10 patients with inoperable locally recurrent head and neck cancer, who underwent SBRT using CyberKnife were analyzed. For each patient, three treatment plans were examined: (1) cone-based without delineation of the ipsilateral internal carotid (clinical plan used to treat the patients); (2) cone-based with the carotid retrospectively delineated and spared; and (3) Iris-based with carotid sparing.

Stereotactic Body Radiation Therapy for Apical Lung Tumors: Dosimetric Analysis of the Brachial Plexus and Preliminary Clinical Outcomes.

Purpose: Dosimetric constraints of the brachial plexus have not yet been well-established for patients undergoing stereotactic body radiation therapy (SBRT). This study evaluated long-term experience with the treatment of early-stage apical lung tumors with SBRT and reports on dosimetric correlates of outcome.

Methods And Materials: Between 2009 and 2018, a total of 78 consecutive patients with 81 apical lung tumors underwent SBRT for T1-3N0 non-small cell lung cancer.

Visualization of meniscus with 3D axial reconstructions.

Purpose: To visualize the meniscus of the knee joint in the axial plane and identify injuries that cannot be visualized using conventional sequences.

Methods: Two hundred and two subjects underwent an improvised 3-Dimensional Proton Density Fat Saturation (3D-PD FS) Magnetic Resonance (MR) sequence on their meniscus. The transverse images were reconstructed and examined.

Coronary Artery Calcifications and Cardiac Risk After Radiation Therapy for Stage III Lung Cancer.

Purpose: Heart dose and heart disease increase the risk for cardiac toxicity associated with radiation therapy. We hypothesized that computed tomography (CT) coronary calcifications are associated with cardiac toxicity and may help ascertain baseline heart disease.

Methods And Materials: We analyzed the cumulative incidence of cardiac events in patients with stage III non-small cell lung cancer receiving median 74 Gy on prospective dose-escalation trials.

NTCP modeling and dose-volume correlations for acute xerostomia and dry eye after whole brain radiation.

Background: Whole brain radiation (WBRT) may lead to acute xerostomia and dry eye from incidental parotid and lacrimal exposure, respectively. We performed a prospective observational study to assess the incidence/severity of this toxicity. We herein perform a secondary analysis relating parotid and lacrimal dosimetric parameters to normal tissue complication probability (NTCP) rates and associated models.

Initial Data Pooling for Radiation Dose-Volume Tolerance for Carotid Artery Blowout and Other Bleeding Events in Hypofractionated Head and Neck Retreatments.

Purpose: Dose-volume data for injury to carotid artery and other major vessels in stereotactic body radiation therapy (SBRT)/SABR head and neck reirradiation were reviewed, modeled, and summarized.

Methods And Materials: A PubMed search of the English-language literature (stereotactic and carotid and radiation) in April 2018 found 238 major vessel maximum point doses in 6 articles that were pooled for logistic modeling. Two subsequent studies with dose-volume major vessel data were modeled separately for comparison.

Objective Assessment of the Quality and Accuracy of Deformable Image Registration.

Background: The increased use of deformable registration algorithms in clinical practice has also increased the need for their validation.

Aims And Objectives: The purpose of the study was to investigate the quality, accuracy, and plausibility of three commercial image registration algorithms for 4-dimensional computed tomography (4DCT) datasets using various similarity measures.

Materials And Methods: 4DCT datasets were acquired for 10 lung cancer patients.

Dose Calculation Comparisons between Three Modern Treatment Planning Systems.

Purpose: Monaco treatment planning system (TPS) version 5.1 uses a Monte-Carlo (MC)-based dose calculation engine. The aim of this study is to verify and compare the Monaco-based dose calculations with both Pinnacle collapsed cone convolution superposition (CCCS) and Eclipse anisotropic analytical algorithm (AAA) calculations.

Prostate Stereotactic Body Radiation Therapy: An Overview of Toxicity and Dose Response.

Purpose: Ultrahypofractionationed radiation therapy for prostate cancer is increasingly studied and adopted. The American Association of Physicists in Medicine Working Group on Biological Effects of Hypofractionated Radiotherapy therefore aimed to review studies examining toxicity and quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer and model its effect.

Methods And Materials: We performed a systematic PubMed search of prostate SBRT studies published between 2001 and 2018.

Prostate cancer tumour control probability modelling for external beam radiotherapy based on multi-parametric MRI-GTV definition.

Purpose: To evaluate the applicability and estimate the radiobiological parameters of linear-quadratic Poisson tumour control probability (TCP) model for primary prostate cancer patients for two relevant target structures (prostate gland and GTV). The TCP describes the dose-response of prostate after definitive radiotherapy (RT). Also, to analyse and identify possible significant correlations between clinical and treatment factors such as planned dose to prostate gland, dose to GTV, volume of prostate and mpMRI-GTV based on multivariate logistic regression model.

Tumor Control Probability Modeling and Systematic Review of the Literature of Stereotactic Body Radiation Therapy for Prostate Cancer.

Purpose: Dose escalation improves localized prostate cancer disease control, and moderately hypofractionated external beam radiation is noninferior to conventional fractionation. The evolving treatment approach of ultrahypofractionation with stereotactic body radiation therapy (SBRT) allows possible further biological dose escalation (biologically equivalent dose [BED]) and shortened treatment time.

Methods And Materials: The American Association of Physicists in Medicine Working Group on Biological Effects of Hypofractionated Radiation Therapy/SBRT included a subgroup to study the prostate tumor control probability (TCP) with SBRT.

Incorporating biological modeling into patient-specific plan verification.

Purpose: Dose-volume histogram (DVH) measurements have been integrated into commercially available quality assurance systems to provide a metric for evaluating accuracy of delivery in addition to gamma analysis. We hypothesize that tumor control probability and normal tissue complication probability calculations can provide additional insight beyond conventional dose delivery verification methods.

Methods: A commercial quality assurance system was used to generate DVHs of treatment plan using the planning CT images and patient-specific QA measurements on a phantom.

Evaluation of a commercial DIR platform for contour propagation in prostate cancer patients treated with IMRT/VMAT.

Purpose: To assess the performance and limitations of contour propagation with three commercial deformable image registration (DIR) algorithms using fractional scans of CT-on-rails (CTOR) and Cone Beam CT (CBCT) in image guided prostate therapy patients treated with IMRT/VMAT.

Methods: Twenty prostate cancer patients treated with IMRT/VMAT were selected for analysis. A total of 453 fractions across those patients were analyzed.

VMAT Optimization and Dose Calculation in the Presence of Metallic Hip Prostheses.

Introduction: This research quantifies and compares the effect of hip prostheses on dose distributions calculated using collapsed cone convolution superposition and Monte Carlo (with and without correcting for the density of the implant and surrounding tissues). The use of full volumetric modulated arc therapy arcs versus volumetric modulated arc therapy arcs avoiding the hip implants (skip arcs) was also studied.

Materials And Methods: Six prostate patients with hip prostheses were included in this study.

Correlation between Biological Effective Dose and Radiation-induced Liver Disease from Hypofractionated Radiotherapy.

Background: The prevention of radiation-induced liver disease (RILD) is very significant in ensuring a safe radiation treatment and high quality of life.

Aims And Objectives: The purpose of this study is to investigate the correlation of physical and biological effective dose (BED) metrics with liver toxicity from hypo-fractionated liver radiotherapy.

Materials And Methods: 41 hypo-fractionated patients in 2 groups were evaluated for classic radiation-induced liver disease (RILD) and chronic RILD, respectively.

Common and Uncommon Artifacts in T1 FLAIR SAG Sequences of MRI Brain.

Objective: This study aims at identifying, classifying, and measuring the frequency the different artifacts that show up in the images of the Sagittal T1 Fluid Attenuated Inversion Recovery (FLAIR) sequence.

Materials And Methods: A total of 101 subjects underwent brain magnetic resonance imaging examination with the following sequences: Axial T1 FLAIR, Axial T2-weighted imaging, Diffusion Weighted Imaging, 2D Multiple Echo Recombined Gradient Echo, Sagittal T1 FLAIR, Coronal T2 Turbo Spin Echo, Spin Echo T1-weighted imaging, and 3D Fast Spoiled Gradient-echo. In these images, we observed the following categories of artifacts: (a) ghost artifacts, (b) aliasing behind the occipital bone, (c) aliasing inside the sphenoid cavity, (d) susceptibility artifacts, and (e) pulsation artifacts.

Validation of different PSMA-PET/CT-based contouring techniques for intraprostatic tumor definition using histopathology as standard of reference.

Purpose: Accurate definition of the intraprostatic gross tumor volume (GTV) is crucial for diagnostic and therapeutic approaches in patients with primary prostate cancer (PCa). The optimal methodology for contouring of GTV using Prostate specific membrane antigen positron emission tomography (PSMA-PET) information has not yet been defined.

Methods And Materials: PCa patients who underwent a [68Ga]PSMA-11-PET/CT followed by radical prostatectomy were prospectively enrolled (n = 20).