Digital tomosynthesis with an on-board kilovoltage imaging device

Area of Science:

• Medical Imaging
• Radiation Oncology

Background:

• Conventional portal imaging and cone-beam computed tomography (CBCT) are used for image-guided radiation therapy (IGRT).
• Digital tomosynthesis (DTS) offers a potential alternative for generating on-board images.

Purpose of the Study:

• To generate on-board digital tomosynthesis (DTS) and reference DTS images for three-dimensional image-guided radiation therapy (IGRT).
• To evaluate DTS as an alternative to conventional portal imaging or on-board CBCT.

Main Methods:

• Three clinical cases (prostate, head-and-neck, liver) were used to demonstrate on-board DTS capabilities.
• Reference DTS images were reconstructed from digitally reconstructed radiographs.
• The effect of scan angle on DTS slice thickness was analyzed.
• A breath-hold DTS acquisition strategy was implemented to mitigate respiratory motion artifacts.

Main Results:

• DTS slices provided more anatomic information than kilovoltage or megavoltage radiographs.
• Breath-hold DTS acquisition enhanced soft-tissue visibility by reducing respiratory motion.
• DTS images showed similarities to coincident CBCT planes.

Conclusions:

• Improved bony and soft-tissue visibility with DTS can enhance target localization accuracy.
• DTS may enable daily soft-tissue target localization.
• Breath-hold DTS is a viable alternative to on-board CBCT, particularly for sites with respiratory motion.