Objective:

To investigate the occurrence of hot spots in adaptive radiotherapy plans for cervical cancer and propose an improved workflow to address these issues.

Approach:

• Case Presentation: A 58-year-old female with cervical cancer underwent adaptive radiotherapy using the Ethos system, which revealed hot spots in the treatment plan due to the proximity of the target to the multi-leaf collimator (MLC) boundary.
• Simulation and Treatment Planning: CT simulation and treatment planning were conducted, including delineation of clinical target volume (CTV) and planning target volume (PTV) with specific dose prescriptions, aiming to optimize treatment delivery.

Key Findings:

• Hot spots were identified in the adaptive treatment plan due to the proximity of the target to the multi-leaf collimator (MLC) boundary, which limited modulation flexibility.
• The automated online adaptive workflow may introduce dosimetric uncertainties, including auto-segmentation errors and suboptimal optimization objectives, affecting treatment safety.

Interpretation:

The study highlights the need for improved workflows in online adaptive radiotherapy to enhance plan robustness and safety.

Limitations:

• The study is based on a single case report, which limits the generalizability of the findings.
• Potential confounding factors in the automated planning process were not fully explored, which may impact the results.

Conclusion:

An improved online adaptive radiotherapy workflow is proposed to reduce the risk of hot spots in adaptive plans for cervical cancer, enhancing treatment safety.