1. Radiation Oncology New Techniques + Technologies
Yo-Yo Chi
Radiation Therapist

2. Coming Up DCAT for SABR lung patients using FFF
DIBH for left sided breast cancer patients
Christchurch Oncology Paediatric Team

3. DCAT for SABR Lung Patients Using FFF

4. SABR / SBRT
Stereotactic Ablative Body Radiotherapy / Stereotactic Body Radiotherapy
Highly precise, image guided dose delivery
Highly conformal ablative dose
Typically ≥8Gy
Tight margin around tumour
Fewer treatments
Typically 1-5 treatments
High max doses in target is allow
SABR of SBRT stands for Stereotactic Ablative Body Radiotherapy and Stereotactic Body Radiotherapy.
This technique involves highly precise, image guided dose delivery – meaning prior to each treatment, with the patient setup in their treatment position we would do a 4D scan, match and do any shifts required.
Highly conformal ablative dose – SABR typically uses dose greater or equal to 8Gy per fraction. And tight margin around the target, minimising the area of normal tissues receiving this high dose as much as possible.
This larger dose also means patients can have fewer treatments – 1-5 treatments, finishing within one or two weeks.
We also allow high maximum doses in target which can be as high as 150% prescribed dose.

5. Fractionations Conventional 60Gy/30#, 2Gy/# SABR/SBRT 45Gy/3#, 15Gy/#
EQD2= 112.5Gy
48Gy/4#, 12Gy/#
EQD2= 88.2Gy
This is comparing the fractionations between conventional treatment and SABR treatment. EQD2 is the equivalent total dose in 2Gy fractionation.
So what this is showing is that our conventional fractionation gives the target 60Gy over 30 treatment. Whereas the SABR fractionation can deliver an equivalent dose of 112Gy to the target.

6. criteria
There are criteria for SABR. The tumour needs to small and cannot be centrally located – it needs to be away from the mediastinum and the bifurcation of lobar bronchi.
So any tumour inside the purple line will not be eligible. That little tumour on the chestwall is perfect for SABR.

7. SABR Treatment Minimum of 8 treatment beams with multiple couch angles
1 hour treatment appointment
Imaging
After setup
Prior to turning radiation on
After treatment
Often patients have difficulty with pain from lying in treatment position for so long
So what does SABR treatment involves?
Minimum of 8 treatment beams with multiple couch angles
1 hour treatment appointment
Imaging
After setup
Prior to turning radiation on
After treatment
Often patients have difficulty with pain from lying in treatment position for so long

8. So… DCAT! Dynamic Conformal Arc Therapy (DCAT)
Dose delivered in a continuous arc
Target remains inside the open field for the entire treatment
So to improve on this great technique, we combined it with DCAT, which stands for dynamic conformal arc therapy.
It is the delivery of dose in a continuous arc with the target remains inside the open field for the entire treatment. This minimises the potential over-shielding of a moving target and is much faster to treat.

9. DCAT
Another Technique

10. Even Better… FFF!
And to make the treatment even better and faster, we combined it with FFF – flattening filter free.
Radiation normally has a peak which the treatment machine will ‘flatten out’ with flattening filter to allow a flat dose for treatment, so more evenly distributed radiation.
But in this technique we take out this filter and use this peak to our advantage. As previously mentioned, we allow high maximum doses in the target so doesn’t matter so much the radiation is evenly distributed. The peak actually allows us to pinpoint the radiation, reducing doses outside the treatment field and lower skin doses.

11. DCAT for SABR Lung Patients Using FFF
Appointment time 1 hour  30 minutes
Radiation “on” time – 1.5 minutes
Faster treatment = less discomfort = less movement
So back to the title – combining all three techniques I mentioned in this talk, it will reduce total appointment time down to 30 minutes with actual radiation on time 1.5 minutes. This will help with reducing patient discomfort and therefore less chance for them to move, thus increasing the accuracy of treatment.

12. Questions?

13. Deep Inspiration Breath Hold
Next technique I would like to talk about is DIBH - Deep Inspiration Breath Hold.
Deep Inspiration Breath Hold

14. DIBH Deep Inspiration Breath Hold
Technique where patient holds breath during treatment
At Canterbury Regional Cancer and Haematology Service – left-sided breast cancer
This is a technique where patient takes a deep breath in and hold this breath for the duration of the treatment. At Canterbury Regional Cancer and Haematology Service, we use this technique on our left-sided breast cancer patients.

15. Left-sided Breast Cancer
Heart sits on the left side
Conventional treatment planning cannot avoid a small portion of heart
Potential side effect is cardiac toxicity
Increase cardiac morbidity
Increase cardiac mortality
This reason being that the heart sits on the left side of the body. While conventional treatment planning minimises dose to the normal tissues as much as possible, a small portion of the heart is mostly unavoidable. This is significant a one of the potential side effect for left-sided breast cancer patients is cardiac toxicity later in life – an increase in cardiac morbidity and mortality.

16. Free Breathing
DIBH
This picture shows how DIBH helps to reduce dose to the heart.
This red lines are the treatment field. Here, to treat the whole breast, part of the heart has to be included. On the other side, exactly the same patient, still treating the whole breast, but this time the patient has taken a deep breath – and instantly the whole treatment field has lifted away from the heart, decreasing the dose to it.

17. How to Achieve Breath Hold
Active Breathing Coordinator (ABC)
Monitor breathing pattern
Holds breath at predetermine lung volume – consistent
Radiation will only turn on in breath hold
Patient is always in control
But then how do we achieve same breath hold each time? We still need the patient to be in the same position every time the radiation turns on.
To achieve this, we use a machine and system called Active Breathing Coordinator. There is a mouth piece that the patient bites on and connects them to the machine, allowing us to monitor patient‘s breathing pattern. Once activated it can hold their breath at a predetermined lung volume, consistently.
We tell the patient that it feels like snorkelling, but I’ve never done snorkelling before so I don’t know what that feels like. I have had a go on the machine itself – you can breath in normally and once you reach the set amount, the machine will stop any flow of air, both in and out. That is when the linear accelerator will turn on and deliver the radiation. As soon as the patient is out of the breath hold, the radiation will stop. It will pick up at where it stopped the next time the patient is in breath hold again.
At all time the patient is in control as well – they have a button they hold down to let us and the machine know they are ready to go into breath hold. At any point in time if they wish to come out of breath hold they can let go of the button and they can breathe normally.
We would coach the patient prior to their planning appointment and that is when we determined what their lung volume is and how many seconds they can hold comfortably.

18. Questions?

19. Christchurch Oncology Paediatric Team

20. Paediatric Team Organise appointments + liase with other teams
Liason for parents and children having RT
Organise buddies
Play sessions
Come up with awesome ideas to make the RT journey FUN!
At Canterbury Regional Cancer and Haematology Service we have an amazing paediatric team.
They organise appointments with other teams such as CHOC and anaesthetics. They are the go to people for parents and children having RT. They organise buddies for children under 16 so these children will always have one consistent person with them through their treatment. They facilitate play sessions.
Most importantly, they come up with awesome ideas to make the RT journey FUN!

21. Play Sessions Generally >3yo Play sessions in CT + TMT
Familiarise children with the department to develop trust and compliance
Sessions consist of department tour and dedicated play session
Child and age dependent
Buddy present to establish relationship with child and family

22. Questions?