Skip to 0 minutes and 15 secondsIn this video, we'll define radiation oncology. I will summarise the main steps of planning and delivery of radiotherapy treatment. I will show the interaction of radiotherapy with other treatment modalities. And finally, I will highlight the perspectives of radiation oncology. Radiation oncology is a multidisciplinary and highly technical specialty. It requires pathology, general medicine, radiology, biology, physics, informatics, and technology knowledge for the treatment of cancer with ionising radiations. Ionising radiations, photons, electrons, or particles damage cancer cells at the level of DNA. We have two main mechanisms of interaction with the DNA. The first one is called direct route. That means ionising radiations break the DNA directly. The second one is called indirect route.
Skip to 1 minute and 24 secondsThat means ionising radiations interact with water inside the cells with release of free radicals which damage the DNA. Radiation oncology is technology dependent. Radium was discovered first in 1898. And the first radiotherapy treatments were implemented in early 1900 with very rudimental machines, especially for skin, bone, and superficial cancer treatment, due to the inaccuracy of the procedures. Then cobalt machines were developed in the 1960s. At the time, all the cancer sites were treatable even though the side effects are quite severe due to the inaccuracy of the technology. Eventually, in the 1980s, 1990s, and in our century, the quality of radiotherapy improved dramatically due to the technology development, linear accelerators, informatics, and imaging were introduced.
Skip to 2 minutes and 35 secondsSo rapidly, we moved from 3D conformal radiotherapy-- that means radiotherapy with two or a few radiation beams-- to intensity-modulated radiotherapy-- that means radiotherapy with modulation of the dose on the target volume-- and highly conformal techniques, like volumetric arc therapy-- that means radiotherapy with one or multiple continuous arcs. Radiotherapy can be given as a single treatment method, or modality, or in combination with surgery and/or chemotherapy. Radiotherapy can be curative. That means we want to cure the cancer. Radiotherapy can be postoperative when surgery has not removed the cancer completely. And finally, radiotherapy can be palliative when we want to reduce symptoms such as pain. Radiotherapy treatment is made of two main phases. The first one is called treatment planning.
Skip to 3 minutes and 38 secondsWe want to define the tumour and the organs at risk and then we want to elaborate the treatment plan. The second one is called treatment delivery. During this phase, and before each session, we have to verify the correct set-up of the patient. And we want to guarantee the accurate dose distribution. So we want to give the high dose to the tumour. And we want to give the low dose to the normal organs. During treatment planning, we have to immobilise the patient. And we can use a mask. We can use a body cast or similar immobilisation devices.
Skip to 4 minutes and 20 secondsWe have to acquire imaging, in terms of anatomical imaging such as CT scan, MRI scan, or we can also use functional imaging such as PET scan. Then, we have to define the target volume and the organs at risk. The definition of the target volume can be optimised using different imaging techniques. For example, we can fuse CT and MRI. We can fuse PET and CT. And we can fuse PET and MRI. Then, the radiotherapy plan is finally worked out with dedicated software, which is able to concentrate the high dose on the tumour and limit the dose to the normal structures. Then, during treatment delivery, we have to check that the patient is correctly positioned.
Skip to 5 minutes and 14 secondsSo before each session of radiotherapy, we acquire some images and compare them to the images acquired during the phase of treatment planning. If there are any differences between the two sets of images, we can move the patient until we reach the correct position. And eventually, we can deliver the dose. It's very important that we check that the high dose covers the tumour and not the normal structures. With modern technologies such as volumetric arc therapy, we are able to paint the high dose on the tumour while sparing the organs at risk.
Skip to 5 minutes and 49 secondsIn fact, the goal of radiotherapy is to concentrate the high dose on the tumour in order to maximise the cancer control and minimise the dose of the normal structures in order to limit the toxicities. As you can see in this graph, the energy of six megawatt photons reaches a peak at a particular depth in the body. With imaging and treatment planning, we can concentrate the peak of the energy on the tumour while we can limit the low energies to the normal tissues. In conclusion, radiation oncology is a multidisciplinary specialty. In the past five to 10 years, the technology development improved dramatically the outcome, while limiting the toxicities related to treatment.
Skip to 6 minutes and 40 secondsRadiotherapy can be given as a single treatment modality or in combination with surgery and/or systemic treatments. Even though it will become the protagonist of the oncology scenario in the next 10, 15 years, due to the extreme personalisation of the treatment on each single patient, with lower biological and economical costs, compared to the other treatment modalities.
The advances of radiotherapy
Dr Stefano Schipani describes the components of radiotherapy treatment and the advances that have been made.
Dr Schipani, a senior lecturer in radiation oncology, is funded by the Beatson Cancer Charity which is committed to further enhancing the experience, treatment, outcomes and well-being of current and former patients and their families/carers at the Beatson Cancer Centre.
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