Clinical Outcome in Patients With Early-Stage Small Cell Lung Cancer Treated With Surgery or Radiation in the Absence of Prophylactic Cranial Irradiation: A Single-Center Retrospective Study.

Purpose: As screening chest computed tomography for patients at high risk for cancer has become more widely accepted, increasing numbers of patients with early-stage small cell lung cancer (SCLC) are being diagnosed. Although surgery is an accepted option for patients with early-stage SCLC, for patients who decline or cannot undergo surgery, stereotactic body radiation treatment (SBRT) is an alternative. Although prophylactic cranial irradiation (PCI) improves survival in patients with limited-stage SCLC, PCI for early-stage SCLC (stage T1-T2) has not been explored.

An Analysis of Clinical Toxic Effects and Quality of Life as a Function of Radiation Dose and Volume After Lung Stereotactic Body Radiation Therapy.

Purpose: To analyze clinical toxicity and quality-of-life (QOL) outcomes among patients with stage I non-small cell lung cancer (NSCLC) after stereotactic body radiation therapy (SBRT) as a function of radiation dose and volume parameters.

Methods And Materials: In this institutional review board-approved study, 55 patients with stage I NSCLC who received SBRT (12 Gy × 4) and completed QOL forms were analyzed. Clinical symptoms and QOL outcomes were measured at baseline and at 3, 6, 12, 18, 24, and 36 months after SBRT.

Technical Note: Comparison of the internal target volume (ITV) contours and dose calculations on 4DCT, average CBCT, and 4DCBCT imaging for lung stereotactic body radiation therapy (SBRT).

Purpose: To investigate the differences between internal target volumes (ITVs) contoured on the simulation 4DCT and daily 4DCBCT images for lung cancer patients treated with stereotactic body radiotherapy (SBRT) and determine the dose delivered on 4D planning technique.

Methods: For nine patients, 4DCBCTs were acquired before each fraction to assess tumor motion. An ITV was contoured on each phase of the 4DCBCT and a union of the 10 ITVs was used to create a composite ITV.

Correlation of normal lung density changes with dose after stereotactic body radiotherapy (SBRT) for early stage lung cancer.

Background And Purpose: To investigate the correlation between normal lung CT density changes with dose accuracy and outcome after stereotactic body radiation therapy (SBRT) for patients with early stage non-small-cell lung cancer (NSCLC).

Materials And Methods: Thirty-one patients (with a total of 33 lesions) with non-small cell lung cancer were selected out of 270 patients treated with SBRT at a single institution between 2003 and 2009. Out of these 31 patients, 10 patients had developed radiation pneumonitis (RP).

Four-dimensional computed tomography-based biomechanical measurements of pulmonary function and their correlation with clinical outcome for lung stereotactic body radiation therapy patients.

Background: Functional image guided radiotherapy allows for the delivery of an equivalent dose to tumor targets while sparing high ventilation lung tissues. In this study, we investigate whether radiation dose to functional lung is associated with clinical outcome for stereotactic body radiation therapy (SBRT) patients.

Methods: Four-dimensional computed tomography (4DCT) images were used to assess lung function.

Single institution experience treating adrenal metastases with stereotactic body radiation therapy.

Objective: The objective of the study is to present our experience of treating adrenal metastases using stereotactic body radiation therapy (SBRT).

Materials And Methods: We retrospectively reviewed patients with adrenal metastases treated using SBRT from 2001 to 2014. Response Evaluation Criteria in Solid Tumors v1.

Long-term Follow-up on NRG Oncology RTOG 0915 (NCCTG N0927): A Randomized Phase 2 Study Comparing 2 Stereotactic Body Radiation Therapy Schedules for Medically Inoperable Patients With Stage I Peripheral Non-Small Cell Lung Cancer.

Purpose: To present long-term results of RTOG 0915/NCCTG N0927, a randomized lung stereotactic body radiation therapy trial of 34 Gy in 1 fraction versus 48 Gy in 4 fractions.

Methods And Materials: This was a phase 2 multicenter study of patients with medically inoperable non-small cell lung cancer with biopsy-proven peripheral T1 or T2 N0M0 tumors, with 1-year toxicity rates as the primary endpoint and selected failure and survival outcomes as secondary endpoints. The study opened in September 2009 and closed in March 2011.

Utilization of a hybrid finite-element based registration method to quantify heterogeneous tumor response for adaptive treatment for lung cancer patients.

Tumor response to radiation treatment (RT) can be evaluated from changes in metabolic activity between two positron emission tomography (PET) images. Activity changes at individual voxels in pre-treatment PET images (PET1), however, cannot be derived until their associated PET-CT (CT1) images are appropriately registered to during-treatment PET-CT (CT2) images. This study aimed to investigate the feasibility of using deformable image registration (DIR) techniques to quantify radiation-induced metabolic changes on PET images.

Development and evaluation of a clinical model for lung cancer patients using stereotactic body radiotherapy (SBRT) within a knowledge-based algorithm for treatment planning.

The purpose of this study was to describe the development of a clinical model for lung cancer patients treated with stereotactic body radiotherapy (SBRT) within a knowledge-based algorithm for treatment planning, and to evaluate the model performance and applicability to different planning techniques, tumor locations, and beam arrangements. 105 SBRT plans for lung cancer patients previously treated at our institution were included in the development of the knowledge-based model (KBM). The KBM was trained with a combination of IMRT, VMAT, and 3D CRT techniques.

To gate or not to gate - dosimetric evaluation comparing Gated vs. ITV-based methodologies in stereotactic ablative body radiotherapy (SABR) treatment of lung cancer.

Background: To compare retrospectively generated gated plans to conventional internal target volume (ITV)-based plans and to evaluate whether gated radiotherapy provides clinically relevant dosimetric improvements to organs-at-risk (OARs).

Methods: Evaluation was performed of 150 stereotactic ablative radiotherapy treatment plans delivered to 128 early-stage (T1-T3 (<5 cm)) NSCLC patients. To generate gated plans, original ITV-based plans were re-optimized and re-calculated on the end-exhale phase and using gated planning target volumes (PTV).

Evaluation of gantry speed on image quality and imaging dose for 4D cone-beam CT acquisition.

Background: This study investigates the effect of gantry speed on 4DCBCT image quality and dose for the Varian On-Board Imager®.

Methods: A thoracic 4DCBCT protocol was designed using a 125 kVp spectrum. Image quality parameters were evaluated for 4DCBCT acquisition using Catphan® phantom with real-time position management™ system for gantry speeds varying between 1.

Characteristics of a novel treatment system for linear accelerator-based stereotactic radiosurgery.

The purpose of this study is to characterize the dosimetric properties and accuracy of a novel treatment platform (Edge radiosurgery system) for localizing and treating patients with frameless, image-guided stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Initial measurements of various components of the system, such as a comprehensive assessment of the dosimetric properties of the flattening filter-free (FFF) beams for both high definition (HD120) MLC and conical cone-based treatment, positioning accuracy and beam attenuation of a six degree of freedom (6DoF) couch, treatment head leakage test, and integrated end-to-end accuracy tests, have been performed. The end-to-end test of the system was performed by CT imaging a phantom and registering hidden targets on the treatment couch to determine the localization accuracy of the optical surface monitoring system (OSMS), cone-beam CT (CBCT), and MV imaging systems, as well as the radiation isocenter targeting accuracy.

Stereotactic Body Radiotherapy for Elderly Patients With Medically Inoperable Pancreatic Cancer.

Objectives: People over the age of 75 years account for approximately 40% of patients diagnosed with pancreatic cancer, many with comorbidities that may limit their treatment options. This study reports on the use of stereotactic body radiation therapy (SBRT) in this population.

Materials And Methods: Twenty consecutively treated patients over the age of 75 with pathologically proven localized pancreatic cancer were included in this retrospective review.

Evaluation of two synchronized external surrogates for 4D CT sorting.

The purpose of this study was to quantify the performance and agreement between two different external surrogate acquisition systems: Varian's Real-Time Position Management (RPM) and Philips Medical Systems' pneumatic bellows, in the context of waveform and 4D CT image analysis. Eight patient displacement curves derived from RPM data were inputted into a motion platform with varying amplitudes (0.5 to 3 cm) and patterns.

Correlation of dose computed using different algorithms with local control following stereotactic ablative radiotherapy (SABR)-based treatment of non-small-cell lung cancer.

Purpose: To retrospectively compute dose distributions for lung cancer patients treated with SABR, and to correlate dose distributions with outcome using a tumor control probability (TCP) model.

Methods: Treatment plans for 133 NSCLC patients treated using 12 Gy/fxn × 4 (BED=106 Gy), and planned using a pencil-beam (1D-equivalent-path-length, EPL-1D) algorithm were retrospectively re-calculated using model-based algorithms (including convolution/superposition, Monte Carlo). 4D imaging was performed to manage motion.

Practical methods for improving dose distributions in Monte Carlo-based IMRT planning of lung wall-seated tumors treated with SBRT.

Current commercially available planning systems with Monte Carlo (MC)-based final dose calculation in IMRT planning employ pencil-beam (PB) algorithms in the optimization process. Consequently, dose coverage for SBRT lung plans can feature cold-spots at the interface between lung and tumor tissue. For lung wall (LW)-seated tumors, there can also be hot spots within nearby normal organs (example: ribs).

Clinical commissioning and use of the Novalis Tx linear accelerator for SRS and SBRT.

The purpose of this study was to perform comprehensive measurements and testing of a Novalis Tx linear accelerator, and to develop technical guidelines for com-missioning from the time of acceptance testing to the first clinical treatment. The Novalis Tx (NTX) linear accelerator is equipped with, among other features, a high-definition MLC (HD120 MLC) with 2.5 mm central leaves, a 6D robotic couch, an optical guidance positioning system, as well as X-ray-based image guidance tools to provide high accuracy radiation delivery for stereotactic radiosurgery and stereotactic body radiation therapy procedures.

Measurement of regional compliance using 4DCT images for assessment of radiation treatment.

Purpose: Radiation-induced damage, such as inflammation and fibrosis, can compromise ventilation capability of local functional units (alveoli) of the lung. Ventilation function as measured with ventilation images, however, is often complicated by the underlying mechanical variations. The purpose of this study is to present a 4DCT-based method to measure the regional ventilation capability, namely, regional compliance, for the evaluation of radiation-induced lung damage.

Dosimetric verification and clinical evaluation of a new commercially available Monte Carlo-based dose algorithm for application in stereotactic body radiation therapy (SBRT) treatment planning.

Modern cancer treatment techniques, such as intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), have greatly increased the demand for more accurate treatment planning (structure definition, dose calculation, etc) and dose delivery. The ability to use fast and accurate Monte Carlo (MC)-based dose calculations within a commercial treatment planning system (TPS) in the clinical setting is now becoming more of a reality. This study describes the dosimetric verification and initial clinical evaluation of a new commercial MC-based photon beam dose calculation algorithm, within the iPlan v.

Impact of fraction size on lung radiation toxicity: hypofractionation may be beneficial in dose escalation of radiotherapy for lung cancers.

Purpose: To assess how fraction size impacts lung radiation toxicity and therapeutic ratio in treatment of lung cancers.

Methods And Materials: The relative damaged volume (RDV) of lung was used as the endpoint in the comparison of various fractionation schemes with the same normalized total dose (NTD) to the tumor. The RDV was computed from the biologically corrected lung dose-volume histogram (DVH), with an alpha/beta ratio of 3 and 10 for lung and tumor, respectively.

Analysis of outcomes in radiation oncology: an integrated computational platform.

Radiotherapy research and outcome analyses are essential for evaluating new methods of radiation delivery and for assessing the benefits of a given technology on locoregional control and overall survival. In this article, a computational platform is presented to facilitate radiotherapy research and outcome studies in radiation oncology. This computational platform consists of (1) an infrastructural database that stores patient diagnosis, IMRT treatment details, and follow-up information, (2) an interface tool that is used to import and export IMRT plans in DICOM RT and AAPM/RTOG formats from a wide range of planning systems to facilitate reproducible research, (3) a graphical data analysis and programming tool that visualizes all aspects of an IMRT plan including dose, contour, and image data to aid the analysis of treatment plans, and (4) a software package that calculates radiobiological models to evaluate IMRT treatment plans.

The investigation on the location effect of external markers in respiratory-gated radiotherapy.

Purpose: To investigate the effect of the marker placement on the correlation relationship between the motions of external markers and the internal target under different breathing patterns for several lung cancer patients.

Method And Material: To monitor and record simultaneous motions of internal target and associated surrogate markers during respiratory gated radiotherapy, an infrared camera system synchronized with a medical simulator was installed in our institute. Multiple external markers were placed on the patients' chest wall with proper geometrical arrangement in closely monitoring the motion of skin near tumor.

Utilize target motion to cover clinical target volume (ctv)--a novel and practical treatment planning approach to manage respiratory motion.

Purpose: To use probability density function (PDF) to model motion effects and incorporate this information into treatment planning for lung cancers.

Material And Methods: PDFs were calculated from the respiratory motion traces of 10 patients. Motion effects were evaluated by convolving static dose distributions with various PDFs.

Evaluation of residual patient position variation for spinal radiosurgery using the Novalis image guided system.

Purpose: The Novalis system has been demonstrated to achieve accurate target localization on anthropomorphic phantoms. However, other factors, such as rotational deviation, patient intrafraction motion, and image fusion uncertainty due to patient body deformation, could contribute additional position uncertainty for actual patients. This study evaluates such position uncertainty for spinal radiosurgery patients.