Better Radiotherapy Technology
The photograph shown above is of Mr Chuan-Dong Wen who recently won a special National Award for his innovative work.
Click here to read: Wen wins AIIA National iAward
This is a classic example that demonstrates initiatives the Foundation wishes to financially support.
Cancer Services
From kilovoltage to Megavoltage X-ray Radiotherapy
Radiation oncology, or more generally called radiotherapy, is a medical specialty that’s primarily used for the radiation therapy of cancer. But there are some non-malignant disorders that radiotherapy also plays a vital role in successfully treating too.
220 KV was the maximum voltage available to produce X-rays for radiotherapy in the ’50s. The method of setting a patient up for treatment was very crude.
The first-generation linear accelerator was able to produce a 4 MV X-ray energy but still the means of treatment set-up were limited.
Progression of the engineering and physics design of linear accelerators has now reached the generation 5 level with very accurate methods of treatment including a means of checking X-ray delivery with imaging equipment.
The medical physicist is expert in radiation dosimetry. The accuracy and validity of the planning and treatment equipment is regularly tested. The medical physicist is also a key contributor to developing new techniques for better radiotherapy treatment.
The water tank is an essential tool for the medical physicist to measure very accurately the X-ray beam dose distribution with a positional accuracy within millimetres. Water has similar mega voltage X-ray beam attenuating properties to normal tissue.
Mr Chuan-Dong Wen is here working on a new technique he is implementing for free breathing respiratory gated stereotactic-beam- radiotherapy (SBRT). It is for a patient with stage I inoperable lung cancer. The patient’s lung tumour moves during the breathing cycle. This technique ensures that the tumour is accurately targeted during the patient’s breathing.
This shows the treatment head of the linear accelerator pointing horizontally and the X-ray head and image detector above and below the patient. The accuracy and calibration of all these accuracy must be regularly checked by the medical physics staff as part of an on-going QA program for radiation safety and quality of patient care.
Physicists and engineers working in radiotherapy have developed many significant improvements for the betterment of patient’s treatment. Through their work, it is now possible to treat and image the patient to target the tumour from all directions while limiting the dose to the normal critical structures.
This is the ‘Electron Tree of Life’ produced by irradiating a block of clear perspex to an extremely high dose of megavoltage electron beam and then hitting the perspex hard with a sharp metal point. It shows very well the arbitrary pathways the electron travel as they pass through the fractured perspex crystalline structure to the point of impact seen at the bottom.
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