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Explain the principles and effects of radiation therapy and the equipment used. Explain how excessive exposure to radiation can cause harm. 04 Evaluate a range of therapy techniques, types of radiation available and the equipment used. Functional skills Literacy Level 2 MET Speaking and listening presenting the result of research into chosen areas Reading researching chosen industrial applications from a wide range of sources Writing writing reports Teacher signature: Date: Sampled for Internal Verification: Y/N (this should form the back of the first sheet) Student Comments: (see separate sheet) Teacher/Assessor comment:

Internal Verifier feedback to Assessor BEET National Extended Diploma Applied Science unit 20 Medical Physics Techniques Assignment 4 Radiotherapy and Radiation Protection 1. Use this diagram to explain how a LIANA works: Electron gun is emitting electron beam through thermion emissions the same as the X-ray tube. The electrons are accelerated to a speed close to the light along with an evacuated tube and in order to generate an X-ray beam, the electrons are being deflected as a general rule to 900 via electromagnets to hit the target.

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The electrons quickly reduce their speed, giving up their energies to high-energy X-radiation because the electron energies involved are so greater compared to X-ray tube. A transmission target is used whereby X-rays are being produced from the long side of the target and directed into the patient. A computer-controlled gantry and treatment couch ensure any treatment position, whereas a dose monitor is used to measure the cumulative dose and to cut off the device at the appropriate time. B) Give two differences between this machine and the cobalt 60 machine.

Instead of using high-energy X-ray beams cobalt-60 machine uses y-rays from radioactive source that could be directed as well as LIANA into a patient to treat a cancer. A great care should be taken to protect the high-activity cobalt source of all time because it decays spontaneously and cannot be switched off compared to LIANA. C) Look at the following photographs of two types of peripherally. Explain the main features of each type including the type of treatment and the possible sources used.

Cervical peripherally Prostate peripherally Cervical peripherally is produced by specially made hollow tubes called “applicators” that are inserted inside the womb or vagina. During the treatment, a machine is used to place the radioactive material inside the applicator and once the treatment is over the machine takes back radioactive material and the applicators is removed. The peripherally could be given into two different treatments(high or low dose rate treatment).

With the botheration’s a same dose of radiotherapy is given, whereas for over a different time. High dose rate treatment is given for a short period of time, whereas low dose are given for longer period of time. Small radioactive seeds of Iodine-1 25 could be inserted where the tumor is located and they are left inside to release their radioactivity slowly. This process sometimes is known as low-dose rate treatment. The seeds are not removed from the patient and eventually fades away for the time of six months.

All of the radioactivity is absorbed by the prostate so therefore it’s safe for the patient to stay next to other people. A second option for prostate peripherally is that the seeds are being placed in specific catheters, which have been inserted inside the prostate gland while the patient was sleeping in the operating theatre. The seeds are put in a specific period of time and then are removed and this recess is known as high-dose rate treatment. Once the treatment is over, the catheters are removed and there is no track of radioactive material inside the prostate gland. ) You are asked to explain the benefits and risks attached to the various uses of radiation in a hospital. A) Draw a flow chart showing the chain of events which can take place when living tissue is exposed to noising radiation. Ensure that your chart includes direct and indirect action, deterministic and stochastic effects. B) Fill out the following table: Radiation Effect Definition Example Somatic It is biological effect that does not affect the gonads so therefore they are not transmitted to the offspring.

An example of somatic effect would be radiation sickness. Genetic Genetic effect is suffered by the offspring of the single exposed. Small dose of ionizing radiation could permanganate’s the DNA in germ cells . C) Use the information in the table to answer the following questions: I) What is the source of the radiation you are exposed to on a flight? The exposure of radiation on a flight that the aircrew and passengers is 2 ms. Ii) Why is this higher than when you are on the ground? It is higher than the ground because of the cosmic rays.

Most of the cosmic rays on the ground are being absorbed by the atmosphere, wherewithal is higher than on the ground the absorption Of these rays is lower. D) The following questions are about doses received from CT (computerized tomography) scans. Examination Typical equivalent dose (ms) chest CT 5. 8 whole torso (chest, abdomen, pelvis) CT 9. 9 I) How many whole torso CT scans would produce a dose that causes immediate radiation sickness? (equivalent dose which causes immediate radiation sickness is mammas) 1000+9. = 101. 1 so therefore approximately 101 typical whole torso CT are needed to causes immediate radiation sickness. Ii) How many chest X-rays would have the same effect as a dose that causes immediate radiation sickness? 1000+5. 8=172. 41 so therefore approximately 172. 41 typical chest CT are needed to cause immediate radiation sickness, e) During radiation testing a health worker is exposed to 1 Foggy of a radiation with quality factor of 20 and Peggy of y rays (SF=l Calculate the total equivalent dose for these radiations. Radiation x quality factor–> 10 x 20 Peggy Total equivalent dose= 200+25= 225 ) What are the two main advantages of megavolt therapy over superficial therapy? It decreases the damage sustained by the patient’s skin. It reduces the damage to the bones. B) Use the diagram below to describe in detail how gamma radiation from a radioactive source is used to treat a tumor in a cancer patient while doing the minimum damage to healthy tissue. For treating tumors deep within the body, higher-energy X-ray photons are required because lower-energy photons are more easily absorbed by the soft tissue.

They do not reach deep enough into the body and could cause image to the tissues that absorb them. Therefore, to do the minimum damage to healthy tissues, different type of beams are used. X-ray are delivered by different beams that meet on the side of the malignant cells and by this way the harm of the surrounding tissue is being reduced. Multiple beam therapy gives short doses of radiation at each of the number of the positions as the diagram shows above 1 , 2 and 3 and only the tumor receives the dose each time.

By rotating the patient around the axis of the tumor the same effect could be obtained. Another way to do this process is by using a ingle beam while rotating the patient around and always aiming the beam towards the tumor. C) What method do you think would be used to ensure that the beam is focused directly onto the tumor? You should consider what needs to be done to keep the patient in one place and how the beam of radiation is precisely focused onto the patient.

In order to minimize the damages in the patient’s body and ensure that the beam is focused directly onto the tumor, a number of low-intensity beams are directed into the patient from different locations. If all the different low- intensity beams combine at the tumor, the dose that would be produced loud be enough to destroy the cancer cells while not damaging healthy tissues around it. This process could be performed by using the multiple and rotational beams, which I have already explained in the previous question. Usually patient lie down on a couch and radiation machines are positioned above the patient.

The therapist may adjust the patient position, the angle and the position of the machine which means that when the machine emits radiation the rays would be focused on the exact part of the body that they want Lead shields could be placed over certain areas of the body of the tenant to protect them from the radiation . Once the patient is being settled inside the machine, the therapist has to leave and go to separate control room. This is done for their own protection from repeated exposure to radiation, whereas in the control room they still see and talk to the patient. ) Peripherally implants a tiny amount of a radioactive material directly into a tumor where it remains for several days. I) The radioisotope iridium-192 often used emits beta particles and low energy gamma rays. Why would this source not be suitable for external beam therapy? Iridium-192 is not a suitable source for external beam therapy because it emits beta particles and low energy gamma rays. In external beam therapy therapist want to destroyable cell,prevent the cancer from coming back and help other cancer treatment work better.

Since, Iridium-1 92 emits beta particles that are less ionizing and more dangerous compared to gamma rays because they are not able to travel to far away inside the body and the soft tissues would absorb them. This would cause many hazardous effects such as damaging Of the cells and DNA molecules that could lead to several cell hanged known as mutations. Ii) Why is it suitable for breathers? Iridium-192 is suitable for breathers because it is a radionuclide with high specific activity, which means that a very small source could provide a very high dose rate.

The effective photon energy of around 350 Kevin ensuring enough absorption dose at a good distance from the source to the treatment target. Iii) What is the main advantage of peripherally over external beam therapy? In peripherally, the radiation is precisely delivered within the body, reducing the risk of unnecessary damages to healthy tissues and organs close o the tumor, whereas in external beam therapy, the radiation has to travel through healthy tissues and organs to reach the tumor.

Therefore more healthy tissues and organs would be exposed to the radiation and that’s why peripherally is better compared to external beam therapy. DO Corrections Task 1 (c) There are two main types of peripherally; Interactivity radiation and interstitial radiation. Both Of the methods are using radioactive implants such as seeds, wires, needles, capsules or tubes. Interactivity peripherally- The radioactive source, which is called implant, re put into a space next to the tumor where is actually located.

This space may be a body cavity such as the cervix, uterus or vagina. Interstitial peripherally- the radioactive source, which is called implant, are put directly into the tissue or near to the affected site, whereas not in body a cavity, such as the prostate or breast. Task 2 b) An example of genetic effects is that the affected cells are the reproductive cells such as the egg and sperm cells. Task 3 (c) Before a any treatments to begin, the specific area that must be target is identified by using a special x-ray machine known as a stimulator.

This machine has a rotating gantry almost the same as the treatment machine whereas instead is fitted with diagnostic X-ray system and an image intensifier. Also the radiation therapist could mark the treatment area on the body of the patient with non-permanent ink. These methods are done because it helps the technicians to line up the radiotherapy equipment correctly. Once locating the perfect position for the treatment, the radiation therapist may mart certain points of patient’s body with a tiny permanent skin mark to make sure that any further treatment are accurately deliver.

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