Commissioning a four-dimensional Computed Tomography Simulator for minimum target size due to motion in the Anterior-Posterior direction: a procedure and treatment planning recommendations.

The purpose of this work is to develop a procedure for commissioning four-dimensional computed tomography (4DCT) algorithms for minimum target reconstruction size, to quantify the effect of anterior-posterior (AP) motion artifacts on known object reconstruction for periodic and irregular breathing patterns, and to provide treatment planning recommendations for target sizes below a minimum threshold. A mechanical platform enabled AP motion of a rod and lung phantom during 4DCT acquisition. Static, artifact-free scans of the phantoms were first acquired.

A method for optimizing planning target volume margins for patients receiving lung stereotactic body radiotherapy.

Lung stereotactic-body radiotherapy (SBRT) places additional requirements on targeting accuracy over standard approaches. In treatment planning, a tumour volume is geometrically expanded and the resulting planning target volume (PTV) is covered with the prescribed dose. This ensures full dose delivery despite various uncertainties encountered during treatment.

Hyperpolarized (3)He magnetic resonance imaging: comparison with four-dimensional x-ray computed tomography imaging in lung cancer.

Rationale And Objectives: Pulmonary functional imaging using four-dimensional x-ray computed tomographic (4DCT) imaging and hyperpolarized (3)He magnetic resonance imaging (MRI) provides regional lung function estimates in patients with lung cancer in whom pulmonary function measurements are typically dominated by tumor burden. The aim of this study was to evaluate the quantitative spatial relationship between 4DCT and hyperpolarized (3)He MRI ventilation maps.

Materials And Methods: Eleven patients with lung cancer provided written informed consent to 4DCT imaging and MRI performed within 11 ± 14 days.

Hyperpolarized (3)He pulmonary functional magnetic resonance imaging prior to radiation therapy.

Purpose: Radiation-induced lung injury (RILI) is the primary dose-limiting toxicity for radiation therapy of the lung, and although the effects of radiation dose on RILI development have been well characterized, the influence of chronic obstructive pulmonary disease (COPD) on the development of RILI and other outcomes is not well understood. The purpose of this small pilot study was to evaluate the relationship between hyperpolarized (3)He magnetic resonance imaging (MRI) measurements of COPD with RILI and 12-month survival in lung cancer patients undergoing radical radiotherapy and to evaluate the feasibility of pulmonary functional MRI as an image guidance∕planning tool for radiation therapy.

Methods: Fifteen non-small cell and small cell lung cancer patients underwent pulmonary function tests, x-ray computed tomography (CT), and hyperpolarized (3)He MRI prior to radical radiation therapy (≥60 Gy).

Hyperpolarized 3He functional magnetic resonance imaging of bronchoscopic airway bypass in chronic obstructive pulmonary disease.

A 73-year-old exsmoker with Global initiative for chronic Obstructive Lung Disease stage III chronic obstructive pulmonary disease underwent airway bypass (AB) as part of the Exhale Airway Stents for Emphysema (EASE) trial, and was the only EASE subject to undergo hyperpolarized 3He magnetic resonance imaging for evaluation of lung function pre- and post-AB. 3He magnetic resonance imaging was acquired twice previously (32 and eight months pre-AB) and twice post-AB (six and 12 months post-AB). Six months post-AB, his increase in forced vital capacity was <12% predicted, and he was classified as an AB nonresponder.

Chronic obstructive pulmonary disease: quantification of bronchodilator effects by using hyperpolarized ³He MR imaging.

Purpose: To evaluate short-acting bronchodilator effects in chronic obstructive pulmonary disease (COPD) by using hyperpolarized helium 3 (³He) magnetic resonance (MR) imaging, spirometry, and plethysmography.

Materials And Methods: Fourteen ex-smokers with COPD provided written informed consent to a local ethics board-approved and Health Insurance and Portability Accountability Act-compliant protocol and underwent hyperpolarized ³He and hydrogen 1 MR imaging, spirometry, and plethysmography before and a mean of 25 minutes ± 2 (standard deviation) after administration of 400 μg salbutamol. Distribution of ³He gas was evaluated by using semiautomated segmentation of ³He voxel intensities, where cluster 1 represented regions of signal void or ventilation defect volume (VDV), and clusters 2-5 (C2-C5) represented gradations of signal intensity from hypointensity (C2) to hyperintensity (C5).

Chronic obstructive pulmonary disease: longitudinal hyperpolarized (3)He MR imaging.

Purpose: To quantitatively evaluate a small pilot group of ex-smokers with chronic obstructive pulmonary disease (COPD) and healthy volunteers during approximately 2 years by using hyperpolarized helium 3 ((3)He) magnetic resonance (MR) imaging.

Materials And Methods: All subjects provided written informed consent to the study protocol, which was approved by the local research ethics board and Health Canada and was compliant with the Personal Information Protection and Electronic Documents Act and HIPAA. Hyperpolarized (3)He MR imaging, hydrogen 1 MR imaging, spirometry, and plethysmography were performed in 15 ex-smokers with COPD and five healthy volunteers (with the same mean age and age range) at baseline and 26 months +/- 2 (standard deviation) later.

Detection of longitudinal lung structural and functional changes after diagnosis of radiation-induced lung injury using hyperpolarized 3He magnetic resonance imaging.

Purpose: Therapeutic radiation doses for thoracic tumors are significantly restricted to decrease the risk of nontumor tissue damage, yet radiation-induced lung injury (RILI) still occurs in over 1/3 of thoracic radiation treatment cases. Although RILI can be clinically monitored using pulmonary function measurements, the regional functional effects of the injury are not well understood. Hyperpolarized 3He magnetic resonance imaging provides measurements of regional lung function and structure with high spatial and temporal resolution; the authors use this tool longitudinally for the first time in seven subjects after clinical diagnosis of RILI in order to better understand regional changes in lung function and structure post-RILI.

Hyperpolarized ³He magnetic resonance imaging: preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease.

Rationale And Objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 ((3)He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for (3)He MRI in detecting the lung structural and functional COPD phenotypes.

Materials And Methods: We evaluated 20 ex-smokers with stage I (n=1), stage II (n=9) and stage III COPD (n=10).

Hyperpolarized 3He magnetic resonance imaging of chronic obstructive pulmonary disease: reproducibility at 3.0 tesla.

Rationale And Objectives: We assessed subjects with stage II and stage III chronic obstructive pulmonary disease (COPD) and age-matched healthy volunteers at a single center using (3)He magnetic resonance imaging (MRI) at 3.0 T. Measurements of the (3)He apparent diffusion coefficient (ADC) and center coronal slice (3)He ventilation defect volume (VDV) were examined for same-day and 7-day reproducibility as well as subgroup comparisons.

Hyperpolarized 3He magnetic resonance imaging of ventilation defects in healthy elderly volunteers: initial findings at 3.0 Tesla.

Rationale And Objectives: Hyperpolarized (3)He magnetic resonance imaging ventilation defects have been observed in subjects with respiratory disorders. We quantified (3)He ventilation defects in elderly and middle-aged subjects who had no history of smoking, respiratory, or cardiovascular disorders.

Materials And Methods: Hyperpolarized (3)He magnetic resonance imaging ventilation defect volume (VDV) and ventilation defect score (VDS) were assessed in eight elderly healthy volunteers (mean 67+/-6 years) scanned twice within 7+/-2 minutes and again 7+/-2 days later.