Aetna released info in February 2018 to bill code 77387 for imaging, Here is the following from ASTRO about this.
Update on Image Guidance Billing for Aetna
February 7, 2018
ASTRO has held ongoing discussions with private payer Aetna regarding proper billing of CT Image Guidance with IMRT Treatment Delivery. Aetna maintains that it is more appropriate to bill 77387-26 instead of 77014. CPT Code 77387 Guidance for localization of target volume for delivery of radiation treatment delivery, includes intrafraction tracking, when performed was created in 2015 and is a carrier priced code. Aetna appreciates that practices may be concerned about the reimbursement of this code and recommends that practices contact them regarding a rate review. ASTRO has steps practices may take to perform a rate review, if appropriate. ASTRO continues to urge Aetna to recognize 77014, G6001, G6002 and G6017. If you have any questions, please contact ASTRO's Health Policy Department.
Separately, Aetna has a radiation therapy payment policy which lists a bunch of codes not paid 60 days prior or post 77301, I recommend logging in to your Aetna account and downloading the Radiation Therapy Payment Policy.