Radiotherapy specialists should possess great skills in physics, medicine and also extraordinary attention is required as there are a great number of parameters that should be defined such as gantry angle, collimator rotation field size and so on. But radiographers are ordinary people who are able to make mistakes. In this case 'human error" will be fatal for the patient. So the main purpose of the use of verification systems to reduce or even to overcome the human error. According to the speakers of the meeting named "verification systems tools or toys" from the patient's point of view the verification systems seemed to be a plus because they permit increasingly sophisticated treatment to be delivered with greater accuracy at a grater speed. Currently verification systems are considered as separate equipment are bid for an addition to liner accelerator and managers have to be persuaded of the additional benefits. making verification system as a standard component of the LinAC is strongly wished because it will ensure universal availability. (the British journal of radiology 71 1998)
Question 2 The radiation may cause damage that's why the patients are not usually treated by X-rays more often than one a year. The amount of radiation used in radiation therapy is measured in grays (Gy), and varies depending on the type and stage of cancer being treated. For curative (radical) cases, the typical dose for a solid epithelial tumor ranges from 50 to 70 Gy, while lymphoma tumors are treated with 20 to 40 Gy. Preventative (adjuvant) doses are typically 20 to 25 Gy.
But there are extra cases when it's strongly recommended and the damage must be minimized. Nowdays scientists at the Royal Marsden Hospital in London are testing a system called intensity modulated radiotherapy (IMRT), in which the doses of radiation are controlled precisely to minimise this unwanted damage. An enhancement of virtual simulation is 3-Dimensional Conformal Radiotherapy (3DCRT), in which the profile of each radiation beam is shaped to fit the profile of the target from a beam's eye view (BEV) using a multileaf collimator (MLC) and a variable number of beams. When the treatment volume conforms to the shape of the tumour, the relative toxicity of radiation to the surrounding normal tissues is reduced, allowing a higher dose of radiation to be delivered to the tumor than conventional techniques would allow.(http://www.wikipedia.org)
In our hospital was admised a man suffering from awful pains. After admission of this patient he was examined and cancer was unfortunately diagnosed. Doctor Brant recommended ablation of urinary bladder and insertion of catheter. The operation took only two hours the ablation was affected successfully. Three days the patient was in the bed after that he was examined the second time. His state was defined as satisfactory but in order to exclude metastases he was prescribed