Ga-68 MAA Perfusion 4D-PET/CT Scanning Allows for Functional Lung Avoidance Using Conformal Radiation Therapy...

Area of Science:

• Nuclear Medicine
• Radiation Oncology
• Pulmonary Medicine

Background:

• Ga-68-macroaggregated albumin ((68)Ga-perfusion) PET/CT is a novel technique for assessing functional lung volumes.
• This imaging modality offers potential for optimizing radiotherapy in non-small cell lung cancer (NSCLC).

Purpose of the Study:

• To evaluate the use of (68)Ga-perfusion PET/CT for functional adaptation of definitive radiotherapy plans in NSCLC patients.
• To compare dose-volume metrics between conventional anatomical and functional lung-based radiotherapy planning.

Main Methods:

• A prospective clinical trial involving 14 NSCLC patients receiving 3D conformal radiotherapy.
• Pretreatment respiratory-gated (4D) perfusion PET/CT was used to define functional lung volumes (perfused and well-perfused).
• Alternate radiotherapy plans were created and optimized to avoid these functional lung volumes, with dose-volume parameters compared.

Main Results:

• Optimizing plans for well-perfused lung significantly improved functional V30, V40, V50, and V60 metrics (P < .05).
• A median reduction of 0.86 Gy in functional mean lung dose (MLD) to well-perfused lung was observed (P < .01).
• Plans optimized for perfused lung showed limited benefit and a potential detriment to functional V5.

Conclusions:

• 4D-perfusion PET/CT demonstrates potential for functional lung avoidance in NSCLC radiotherapy planning.
• Adapting radiotherapy plans to well-perfused lung volumes, but not all perfused volumes, effectively reduces radiation dose to functional lung using 3D conformal techniques.