Radiation Therapy at BVSC – Leading the Way

Cancer has many forms and affects the body differently depending on the type, location, grade, and stage, among other things. At BVSC, equipment like our Linear Accelerator allows us to deliver therapeutic, high-energy radiation, giving us the remarkable ability to effectively treat many cancers that might otherwise be untreatable.

Stereotactic radiation Therapy (SRT), sometimes called Stereotactic Arc Body Radiation (SABR), is a very modern technology that has revolutionised radiation therapy and proven effective in treating humans with cancer. Importantly, this form of radiation is powerful and requires exquisite precision from highly advanced machines which enables the treatment of some tumours that were previously considered untreatable.

It is not just the amazing equipment and facility; it is the experience and expertise of our radiation therapy team that makes the magic happen. Our team ensures the side effects are minimal, the animals’ quality of life is maximised, and owners and referring vets are empowered and remain advocates for our patients. We surround our patients and referring vets to provide our signature specialty care with compassion, resulting in the best cancer treatment outcomes possible.

BVSC is part of network called ONE Cancer Care for pets, bringing together board certified radation oncology, medical oncology and surgical oncology to surround our patients with comprehensive cancer care.

How is Radiation Therapy performed at BVSC?

Depending on tumour and patient variables, high energy beams of photons or electrons that disrupt the cancer cell DNA are accurately delivered in as few as 3 to as many as twenty fractions. Sometimes the fractions are delivered on a daily basis and sometimes they are given weekly. Our radiation oncologist has years of experience and training, allowing them to advise on the best prescription of radiation for each individual pet.

Which cancer types are treated with Radiation Therapy?

Some cancers can only be treated effectively with radiation, such as intranasal cancer and some brain cancers. There are cancers that respond well to a combination of surgery and radiation, such as some soft tissue sarcomas and mast cell tumours. Sometimes chemotherapy or other anticancer medications are used before, after, or in conjunction with radiation therapy depending on the cancer type, grade, and stage. Other cancers we may commonly treat with radiation include thyroid cancers, apocrine gland adenocarcinoma, melanoma, pituitary tumours, and many more. Our radiation oncologist can help with advice on where radiation can be very effective and also advise when radiation may help decrease pain and be used in a palliative sense, such as for certain bone cancers. Remember, we surround the patient with care, and our surgical, medical and radiation therapy team work in close collaboration to ensure we deliver specialist care with compassion.

Why should I choose BVSC as the place for my pet to be treated with radiation therapy?

A key reason is that we provide specialty care with compassion and we surround your pet with this care from all our team while keeping your family veterinarian involved and in the loop. This is a team effort, and we know how important your pet is. We have been irradiating animal cancers for longer than anyone in Australia and our radiation therapy facility has been functioning continuously since November 2007.

At BVSC we have the amazing advanced capabilities offered by our very own onsite VarianTM TrueBeamTM linear accelerator providing submillimeter precision in dose delivery. With this advanced technology and our wealth of experience our patients receive the best care. We know how to look after your important family member and support you as well. Another distinction is that our linear accelerator, which is dedicated for animal treatment, is on-site at BVSC giving safe access to all the hospital’s advanced facilities. Our facility is designed to look after animals and your pet has direct access to all our specialist and expert teams if needed. Oncology is what we do, and we are continuously improving, researching and developing newer and better ways to fight cancer.

Frequently Asked Questions

When the radiation beam is on and directed at the patient, there is no feeling at all. It is just like when you receive an X-ray at the hospital. Accurate and repeatable positioning of the patient is absolutely critical, and the effectiveness of the treatment is partly predicated by accurate delivery of the radiation dose to exactly the same area each fraction. To allow this to happen, our animal patients are irradiated while they are anaesthetised and comfortably placed in custom made cradles. Anaesthesia is light enough just to keep your pet still, allowing animals to go home quickly after each fraction.

While there is always some risk for any patient going under anaesthesia, there are several steps we take to minimise the risks such that the likelihood of any problem or complication is extremely unlikely.

We are very good at minimising the side effects in animals. We can also predict what the effects will be because the planning process accurately calculates the radiation dose that the cancer and surrounding normal tissues will receive. This allows our radiation oncologist to tell you almost exactly what the effects will be and to “dial down” and protect normal tissues wherever possible. The predicted side effects, both acute and late effects, will be discussed and the ways to manage and minimise discomfort will be implemented.

Generally not – the systemic effects of radiation are avoided because the beam is accurately directed to a local or regional area. Only the tissues in the beam are exposed to high energy radiation so there is virtually no effect on the entire body.

No. Your pet will not be radioactive. The radiation does not stay in the tissues or in the body and only effects the tissues within the beam field for the short period of time the beam is on.

Some cancer cells do die acutely after being irradiated, but most do not. There is a cumulative effect of the radiation fractions, and eventually there is enough damage to the DNA of the cancer cells so that when the cancer cells try to divide, the DNA falls apart and the cells die. Normal tissue cells have ways of repairing this DNA damage, so the normal cells are much more likely to survive. Besides causing strand breaks in the DNA, radiation can also indirectly damage cells by interacting with oxygen in the tissues to form unstable oxygen species called free radicals. These molecules can damage cells, including cancer cells, causing cell death. Therefore, cancers with abundant oxygen supply are more likely to be damaged through this mechanism compared to cancers with a poor blood supply.

We advise our clients to avoid giving their pet antioxidants during a course of radiation therapy. Antioxidants mop up the free radical oxygen species that play a role in killing cancer when tissue is irradiated. These can be used after the radiation course is completed.

Some animals receive their radiation in as few as three to five fractions generally separated by a week. Usually, these animals only stay long enough to be evaluated, anaesthetised, treated and recover. Typically, this takes most of the morning, so they are ready to go home in the early afternoon. For those animals being treated every day (Monday through Friday for 10 to 20 fractions), the same applies but it does mean they need to be ready to receive their radiation dose every week day morning at about 7:30. For pets who live a long way from BVSC, it is sometimes easier for them to stay overnight during the week. For these patients, we have a special low price for the overnight stay. During their stay, they are well looked after. BVSC is staffed by our qualified and expert teams 24 hours a day, every day of the year, and our long distance patients who stay for the duration of their treatments receive VIP care and special privileges.

A key reason is that we provide specialist care with compassion and we surround your pet with this care from all our team, while keeping your family veterinarian involved and in the loop at all times. This is a team effort and we know how important your pet is to you and your family. We have been treating animals with cancer for longer than anyone in Australia and our radiation therapy facility has been functioning continuously since November 2007, so we have more experience irradiating animal cancers than anybody in Australia. We know how to look after your important family member and support you as well. Another distinction is that our linear accelerator, which is dedicated for animal treatment is on-site at BVSC. Our radiation oncologist, radiation therapists, and the nursing team are right here. There is no need to transport your pet to a human facility. Our facility is designed to look after animals and your pet has direct access to all our specialist and expert teams if needed. Oncology is what we do, and we are continuously improving, researching and developing newer and better ways to fight cancer.

Radiation planning is a carefully structured process in which a team of specialists, including radiation oncologists, medical physicists, and radiation therapists, work together to ensure that radiation is delivered accurately and safely to treat conditions like cancer. The goal is to target the tumour or affected area precisely while minimizing damage to healthy tissues.

Here’s a breakdown of key components involved in radiation planning:

1. Contouring

Contouring is the process of outlining the tumour and surrounding tissues on the images (such as CT scans or MRIs) to define the areas that need treatment. The radiation oncologist identifies the tumour, nearby organs, and any critical structures that need to be protected. This step is crucial because it sets the boundaries of the treatment area, ensuring that radiation is directed precisely where it’s needed.

2. Prescription

The prescription is the plan that specifies the details of the radiation treatment. It includes the dose of radiation to be delivered, the number of treatment sessions (or fractions), and the specific areas to be treated. The radiation oncologist will prescribe the exact amount of radiation to treat the tumour effectively, balancing the need to target the tumour with the need to protect healthy tissues.

3. Forward Planning

Forward planning is the step where radiation therapists use the contoured images to design how the radiation will be delivered. This involves determining the angles, paths, and shapes of the radiation beams. They calculate the best way to focus the radiation on the tumour while sparing nearby healthy tissue as much as possible.

In advanced treatments like Stereotactic Radiation Therapy (SRT), forward planning helps the team figure out the precise setup for delivering highly focused beams of radiation from multiple angles.

4. Quality Assurance (QA) and Physics Check

Before starting treatment, a quality assurance (QA) check is done to ensure everything is set up correctly. The medical physicist will check the radiation equipment and verify that the correct dose and beam angles are programmed. This step is vital to ensure that the treatment is delivered safely and as planned.

The physicist will also confirm that the patient’s positioning devices (like body moulds) are properly set up and that the radiation machine (TrueBeam linear accelerator) is functioning as it should. This helps catch any potential errors before treatment begins.

5. Verification

Verification involves checking that the patient is positioned correctly for each treatment session. This step ensures that the tumour remains in the exact location where the radiation will be delivered. The medical team will often use imaging technologies, like cone beam CT, to verify that the patient’s position matches the treatment plan before each radiation fraction (session). This step is important for ensuring that radiation is aimed accurately at the tumour and not at healthy tissue.

6. Approval

Once the treatment plan is developed, the radiation oncologist and medical physicist review and approve it. This is the final step where the team confirms that everything is in place and the plan is safe and effective. Only after approval will the patient begin radiation treatment.

Why is Radiation Planning Important?

Radiation planning is crucial because it ensures the most precise and effective delivery of radiation, helping to treat the cancer while minimising harm to surrounding healthy tissues. It reduces the risk of side effects and maximises the chances of successful treatment. Each step—from contouring to approval—helps ensure that the patient receives the right dose of radiation in the right way.

A simulation CT is a special type of CT scan used in the planning stage of radiation treatments, such as Stereotactic Radiation Therapy (SRT). This scan produces detailed, three-dimensional images of the area to be treated, helping the veterinary team precisely locate the tumour, its size, and its shape. These detailed images are essential for mapping out the exact area that needs to be targeted with radiation.

Why is a Simulation CT Necessary for SRT?

Stereotactic Radiation Therapy (SRT) delivers high doses of radiation in a very precise way to treat tumours. Because the radiation needs to be targeted to the tumour while sparing healthy surrounding tissue, accurate planning is key. The simulation CT provides the foundation for this planning, offering a detailed “map” of the tumour’s exact location and size. Without this initial scan, the team would not be able to pinpoint the tumour accurately or ensure that the radiation is delivered in the safest, most effective way.

Positioning Devices for Accurate Repositioning

For SRT to be effective, it’s critical that the patient (whether a dog or a human) is positioned the same way during each treatment. Even small changes in position could lead to the radiation being delivered to the wrong area, reducing the effectiveness of the treatment or affecting healthy tissue. This is where positioning devices come into play.

  1. Body Moulds:
    A body mould is a custom-made cast or mould that fits the shape of the patient’s body, holding them in a stable position during radiation. These moulds are created from the simulation CT images and ensure that the patient remains in the same position throughout the treatment process, preventing any movement that could affect the precision of the radiation.
  2. Bite Blocks:
    Bite blocks are used to stabilize the head, especially when the treatment area is near the head or neck. The dog will bite down on the block, keeping the head in the same position for every session. This is important to ensure the radiation is directed precisely at the intended target, especially in cases where even slight movements could affect the treatment outcome.

Using the Simulation CT for Cone Beam CT Indexing

One of the key aspects of SRT is delivering radiation with submillimeter accuracy. After the initial simulation CT, a cone beam CT is taken before each radiation fraction (treatment session). The cone beam CT provides a more real-time, 3D image of the patient’s position right before each treatment. It allows the radiation team to confirm that the patient is in the correct position and that the radiation will be delivered exactly where it’s needed.

The simulation CT is used as a reference to “index” or align the cone beam CT images taken before each SRT fraction. This indexing process ensures that the radiation is always targeted precisely, down to a submillimeter level of accuracy. By using these two imaging techniques together—simulation CT for planning and cone beam CT for verification—veterinary teams can ensure that the tumour receives the full dose of radiation while minimizing the risk of affecting surrounding healthy tissue.

In Summary:

  • The simulation CT is a crucial first step in planning SRT, providing the detailed 3D images needed to map out the tumour’s exact location and size.
  • Positioning devices like body moulds and bite blocks ensure the patient stays in the same position during each treatment session, contributing to the accuracy of radiation delivery.
  • The simulation CT serves as a reference for the cone beam CT taken before each fraction of SRT, allowing the team to verify the patient’s positioning and ensure submillimeter accuracy in delivering the radiation dose.

Together, these techniques and devices help ensure that SRT is as effective and safe as possible for the patient, offering the best chance for successful treatment with minimal side effects.

Stereotactic Radiation Therapy (SRT) is a special type of radiation treatment used to target and treat cancerous tumours with incredible precision. In simple terms, it delivers high doses of radiation to a tumour in the body, but it is very careful about only hitting the tumour and not the healthy surrounding tissue.

How does it work?
SRT uses advanced imaging technology (like CT scans) to map the tumour exactly. The radiation is then delivered from different angles to focus directly on the tumour, almost like a 3D targeting system. This allows the doctors to hit the tumour with strong radiation, while keeping the rest of the body safe.

Why is it special?
What makes SRT different from regular radiation therapy is its extreme precision. It can target a tumour with submillimeter accuracy, meaning the radiation is delivered exactly where it’s needed, even if the tumour is in a tricky spot, like near sensitive organs. SRT usually requires the patient to be in a fixed position for each treatment, which is why positioning devices (like moulds or bite blocks) are used to help keep them still.

SRT is often used for tumours that are hard to operate on or treat with other methods, making it a valuable option for certain types of cancer in pets. It’s a way to give a high dose of treatment while minimizing the risk of harm to healthy tissue.

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