Radiotherapy remains a major treatment for most tumour types and it takes minutes to delivery each radiotherapy dose. The major problem is that patients continue to breathe during these minutes of treatment, so all tumours in the chest and abdomen move with breathing during treatment. This respiratory motion necessitates having to irradiate healthy tissue surrounding the tumour in order to guarantee tumour irradiation. The principal side effects of radiation are: first the damage to all nearby healthy tissue (that limits the duration of any one treatment session), secondly the particular damage to nearby vital organs at risk (usually major blood vessels, airways and gastrointestinal tract).
Chest and abdominal cancer treatment is a major burden in Western healthcare medicine so improvement in its delivery is of major importance to society.
In the United Kingdom I previously developed 2 potentially major advances in respiratory motion management. First to use non-invasive mechanical ventilation in conscious, unmedicated patients to regularize their breathing pattern. This makes constant the size and timing of each breath. Hence it could be much easier for radiotherapy machines to target tumours accurately and to avoid hitting healthy tissue. Secondly, to prolong breath-hold duration by 5 fold by combining hypocapnia induced by mechanical ventilation with breathing 60% oxygen. Hence respiratory motion could be greatly reduced and potentially abolished.
The overall scientific and training objectives of the project were to collaborate with a range of radiotherapy technicians (RTTs), medical physicists and oncologists to
• Train Netherlands staff to deliver my techniques of non-invasive mechanical ventilation to regularize patients breathing and of prolonged breath-holds
• Train healthy volunteers and patients in the Netherlands to accept non-invasive mechanical ventilation
• Use magnetic resonance imaging (MRI) on volunteers and patients to collect data to quantify the improved management of internal motion of relevant structures in the chest and abdomen
• Use this motion quantification to demonstrate objectively the reductions in tumour motion during mechanical ventilation compared to current treatment during spontaneous breathing
• Use simulated treatment plans to quantify the reductions in estimated radiation dose to healthy tissue that mechanical ventilation will achieve and hence make the case for clinical implementation of mechanical ventilation
• Disseminate this information to relevant clinical staff (radiotherapy technicians [RTTs], medical physicists and medical oncologists) and patient groups to encourage adoption of mechanical ventilation
