Table 5.
Overview of anatomical changes during radiotherapy treatment.
| Frequent changes | Cause (most likely) | Number of patients | Consequence |
|---|---|---|---|
| Reduction of GTV volume | Treatment-related | 16 9 (SCC) 7 (AC) |
Displacement of other mediastinal structures/organs, e.g. trachea, with respect to the reference CT |
| Change in diaphragm position | Different breathing pattern | 15 | Difference between bone match and soft tissue match |
| Large reduction in heart volume (>10%) | Unknown | 10 | Displacement of other mediastinal structures/organs, e.g. oesophagus, with respect to the reference CT |
| Rare changes | Possible explanation | Number of patients | Consequence |
| Air in oesophagus | Obstruction, air swallowing | 2 | Difficulties in soft tissue match |
| Air in stomach / bowel | Air swallowing, (carbonated) drinks | 2 | Difficulties in soft tissue match |
| Lateral displacement of oesophagus | Difference in lung filling left vs right | 1 | Difficulties in soft tissue match |
| Anatomical changes in oesophagus outside the radiation field | Treatment-related | 1 | No direct consequences |
| Changes in fatty tissue around the oesophagus | Treatment-related | 1 | No direct consequences |
| Displacement of tumour marker clips | Tumour regression/migration of clips | 1 | Clips not usable to determine accuracy of the match |