Ventilation Using Radiographic Examination: Functional Lung Imaging Techniques for the Reduction of Toxicity in Functional Avoidance Radiation Therapy

The goal of this observational validation study is to determine the best implementation of fluoroscopic and CT ventilation imaging in patients having non-stereotactic ablative body radiotherapy (non-SABR) radiotherapy for stages II-IV lung cancer. The main questions it aims to answer are: * Assess the dosimetric variation in functional avoidance radiation therapy (RT) plans produced using these ventilation imaging techniques, * Establish a quality assurance procedure for functional lung avoidance radiation therapy, and * Evaluate the clinical acceptable thresholds for accuracy of the method. Participants will: Prior to radiation therapy treatment, patients will undergo: 1. A standard of care 4DCT scan for radiation therapy simulation, 2. Pulmonary Function Tests (PFT) 3. A 4D attenuation correction CT 4. Breath Hold Computed Tomography (BHCT) imaging where static end-inspiration and end-expiration BHCT scans will be acquired, 5. Nuclear medicine imaging where a Tc-99m MAA SPECT perfusion scan and a Galligas PET ventilation scan will be acquired, 6. Fluoroscopy where 1-breath cine-fluoroscope sequences will be acquired at five different angles across the chest, 7. A 4D Cone Beam Computed Tomography (4DCBCT) scan. 8. Scans in points 4 to 7 above will be repeated at the end of treatment. Individual participants provide their own internal control. Galligas PET ventilation images (control) are compared with ventilation images derived from additional scans (comparator) for each participant. Tc-99m MAA SPECT perfusion images (control) are compared with perfusion images derived from BHCT scans (comparator) for each patient. There will be no change to patient treatment and patients will be treated using a standard of care anatomical based treatment plan. The pre-treatment 4DCBCT scan is part of standard of care.

Lung cancer is the leading cause of cancer mortality worldwide with non-small cell lung cancers (NSCLC) accounting for approximately 85% of all lung cancers diagnosed. Surgery, immunotherapy, chemotherapy, targeted therapy, and radiation therapy may be used alone or in combination for lung cancer treatment depending on the cancer staging. Radiation therapy is a primary component of lung cancer treatment with 77% of lung cancer patients having evidence-based indication for external beam radiotherapy at some point through their treatment journey. Radiotherapy is associated with radiation-induced toxicities such as radiation pneumonitis and fibrosis that adversely impacts a patient's quality of life and limits the dose that can be safely delivered. Radiation pneumonitis is the inflammation of lung tissue with symptoms such shortness of breath, cough, and fever, manifesting 4 to 12 weeks following the completion of a radiotherapy course. Symptomatic pneumonitis, defined as grade 2 or higher, has an overall incidence of 29.8% with conventional radiotherapy. Current radiotherapy treatment planning assumes that lung function is homogeneous throughout the organ and does not account for regional differences in lung function. These regional differences may arise from the cancer growth itself via tumour compression of lung structures, or from pre-existing, often smoking-induced factors which can also impact the lung health of cancer patients. Pre-existing conditions that can impact lung health include chronic obstructive pulmonary disease (COPD), fibrosis and thickening of the lymphatics in the lung, emphysema, asbestosis and partial lung collapse or side effects from previous cancer treatment such as fluid in the lungs, inflammation and pneumonitis, or even partial lung removal. In order to give patients the best quality of life after radiotherapy, it is crucial to preserve as much healthy lung as possible during the course of treatment. Functional lung avoidance treatment planning for radiotherapy has the potential to reduce pulmonary toxicity by minimising irradiation of healthy lung tissue based on functional maps of the lung. Nuclear medicine functional lung images have been previously incorporated into radiotherapy treatment planning for the purposes of reducing mean doses to functional lung and hence radiation-induced toxicity. Normal tissue complication probability (NTCP) models have also predicted an overall reduction of 6% and 3% for grade 2+ and 3+ radiation pneumonitis, respectively, with functional planning while honouring dose constraints to the target and organs at risk. Nuclear medicine scans are expensive, time consuming and not available in all institutions. CT ventilation imaging has been developed as a cheaper and more accessible alternative to nuclear medicine for mapping the healthy areas of the lung as part of routine pre-treatment CT acquisition. The key steps in CT ventilation imaging are: 1. Acquire CT images of the lung at e Покажи пълното описание...

Inclusion Criteria: * Aged 18 years or older. * Eastern Cooperative Oncology Group (ECOG) performance status 0-2. * Histologically proven Stage II-IV non-small cell lung cancer as determined using the IASLC International Association for the Study of Lung Cancer (IASLC) 8th edition lung cancer staging guidelines. * To be treated with curative intent (stage II-III) or palliative intent (stage IV) with non-SABR external beam radiotherapy (e.g. 60 Gy in 30 treatments for curative intent or 30 Gy in 5 treatments for palliative intent). * Pulmonary function tests within 8 weeks of registration. * 4DCT simulation for radiation therapy. * Willingness to give written informed consent. * Willingness and ability to comply with the study procedures and visit requirements. * Available for follow up for 1 year or until death, whichever occurs first. Exclusion Criteria: * Prior radiation therapy to the thorax. * Prior surgery for this cancer. * Prior chemotherapy for this cancer. * Interstitial lung disease. * Pregnant women.