Assessing Radiation Pneumonitis Through Functional Lung Imaging: A Single Photon Emission Computed Tomography...

Area of Science:

• Radiation oncology
• Medical imaging
• Pulmonary medicine

Background:

• Symptomatic radiation pneumonitis (SRP) is a significant concern for lung cancer patients undergoing radiotherapy.
• Accurate prediction of SRP risk is crucial for optimizing treatment plans and minimizing toxicity.
• Current methods for risk assessment may not fully capture functional lung parameters relevant to radiation-induced lung injury.

Purpose of the Study:

• To develop predictive models for symptomatic radiation pneumonitis (SRP) risk in lung cancer patients.
• To utilize single-photon emission computed tomography (SPECT) for functional lung volume identification and dosimetric analysis.
• To enhance the accuracy of SRP risk stratification using functional lung imaging.

Main Methods:

• Retrospective analysis of 71 lung cancer patients who underwent SPECT before radiotherapy.
• Co-registration of perfusion and ventilation SPECT images with planning CT to define functional and anatomical lung volumes.
• Development and evaluation of Cox regression models incorporating SPECT-derived dosimetric parameters for SRP risk prediction.

Main Results:

• 19 out of 71 patients (26.8%) developed SRP at a median follow-up of 16.8 months.
• Significant SRP risk factors included planning target volume and various SPECT-based dosimetric parameters (pVf10, vVf10).
• A model incorporating ventilation-based SPECT parameters showed the best performance (AUC = 0.819).

Conclusions:

• SPECT-derived dosimetric parameters from perfusion and ventilation are significantly associated with SRP risk.
• Integrating SPECT imaging into risk assessment models can improve the stratification of lung cancer patients.
• SPECT-based dosimetry may facilitate the implementation of lung-sparing strategies in radiotherapy planning.