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Medical Physics 2
Transcript of Medical Physics 2
- can be injected, inhaled or swallowed.
- Image can be taken over a period of several hours once radioisotope is introduced.
- Image shows rate of distribution, absorption and excretion of radioisotope.
- High concentration = Hot Spot
- Low Concentration = Cold spot.
- Hot Spots and Cold Spots may indicated disease. Optical Fibers Another Technique is... And lastly... Lasers Endoscopes The Parts of an Endoscope The Shaft is:
- 10mm in diameter, up to 2 meters long.
- contains fibers which are protected by helical steel bands inside steel mesh.
- Outer coating is covered in plastic to protected it from chemical damage, make it waterproof and easy to move throughout the body. Laser stands for Light Amplification by Stimulated Emission of Radiation
This table outline just some of the current ranges of lasers and their uses. Bibliography 1.Jarcanda Physics 1
21. http://laughingsquid.com/radiation-safety-posters-from-1947/ Safety Procedures
and Issues - Areas where work is carried out with ionizing radiation must be clearly marked as controlled areas with limited access
- Equipment is must be checked regularly to make sure it does not leak radioactive material.
- Personal are to distance themselves from radioactive material where possible, and to wear monitors to measure their exposure to radioactive sources.
- Monitiors must be Checked regularly. - Half life of 6 hours
- Used to produce images and as diagnosis tool
- Measures Hearts efficiency as a pump.
- Can take images of the bones through uses of phosphate ions labeled with Technetium-99m
- Can be used as a tracer to measure blood flow through the brain, allowing for identification of dementia and stroke damage.
- To study blood flow in lungs Technetium-99m Iodine-123 - Half Life of 13 hours
- Used in procedures to gain an image and identify swelling in thyroid gland or goitre.
- Thyroid gland metabolizes iodine.
- Image is taken over 10min- 48hr time interval, allowing image to be taken and uptake of isotopes to be graphed and compared to a standard. Left: Graph of uptake of isotopes in thyroid gland
Above: Image showing an enlarged thyroid gland with an abnormal decrees and uptake. - Use Total Internal Reflection
- Light travels through cables by
reflecting off cables inner walls,
allowing information to be sent along
the cable and an image to be obtained
at the recieving end.
- Allow light to travel long distances
- Made by pulling pure glass into long fine strands - Use optical fibers,
- Used to view the internal organs
- Contain a bundle of up to 10 000 optical fibers.
- Many modern endoscopes now use video chips for better imaging rather than fiber optics. The Shaft contains:
- Non-coherent Fiber Optic bundles (were optical fibers are not lined up at both ends) used to guide the light to an area to be examined, which must be transmitted back to coherent Fiber Optic bundles (lined up at both ends) to produce an image for viewing.
- Water Pipes are used to wash distil face of the endoscope to keep optical section clear.
- Control cables operate the way the distil end is bent
- Additional optional channel carries air or CO2 from
the distil end. Distil End: This end is inserted into the patient body, where the controls on the viewing end allow it to be bent in certain direction to gain an image. This image can be focused by a lens on the end. - Are less invasive than open surgery
- Require only a small incision rather than the deep incisions.
- Recovery is quicker and with less swelling, scarring and risk of infection.
- Are not purely at hospital's but at outpatient departments, as well.
- Examples of endoscopes uses in medical treatment are… Uses of Endoscopes - A surgical procedure in which the internal structure of a joint is examined for diagnosis and to carry out repairs such as removing cartilage.
- Performed by inserting the endoscope through tiny incisions near the joint. The endoscope is connected to a video camera which projects an image of the interior of the joint onto a screen.
- The size of the endoscope can vary depends on the size of the joint being examined,
For example the endoscope for the knee is 5mm in diameter, the wrist is 0.5mm. Two machines that use
these techniques are.... - A surgical procedure used to look for for the source of problems such as bleeding from the lining of the esophagus, stomach and duodenum or ulcers.
- Preformed by having a small flexible endoscope enters through the mouth, advances through the pharynx, esophagus, stomach, and duodenum.
- Air is blown into the cavity to distend the lumen and aid in viewing. Gastroscopy (esophagogastroduodenoscopy) Arthroscopy - Lasers are very effective in Medical Physics,
- Great tool for many different purposes.
- Great as a cosmetic tool, effectively removing birthmarks and tattoos.
- Great as a restorative, corrective and remedial tool
- Providing an alternate option to open surgery, such as in the case of eye surgery, where they are the best way to lower Intraocular pressure (fluid pressure behind eye). Although they are also useful in neurosurgery and dermatology.
- Therapeutic low intensity lasers are a great way to help boost the healing process with a 95% success rate as they interact with the body at a molecular level helping to aid body in its own natural process. Laser's in Medical Physics MRI/X-Ray
Comparison Table Broken Ankles X-Ray MRI Brain Tumor X-Ray MRI Lung Cancer MRI X-Ray Red indicates area of reduced brain activity due to stroke damage Image of a lunge (A) Normal Perfusion and Ventalation study. (B) (i) Perfusion study with blocked left lung. (ii) Ventalation study normal Heart, with 'cold spot on top image indicate a lack of blood flow to left side showing stress, two equally distributed radioisotopes on both sides on bottom shows rest Left: uptake into sites of high bone turnover which occurs in Paget’s disease
Center: bone metastases from breast cancer
Right: extensive uptake in forearm bones after an inadvertent injection of scanning agent into the bronchial artery 1947 Radiation Safety Poster The MRI image is sharper and clearer than that of the X-ray providing more detail. Both images however are clear enough to easily diagnose and interpret what kind of break or fracture has occurred. The MRI image is sharper and clearer than that of the X-ray providing more detail, as it allows us to get a better idea of the structure of the brain. The X-ray however just shows a basic structure with a dark spot where the tumor is located. Although in the X-ray the tumor however is easier to identify. The tumor in the MRI it is less obvious, making it harder to locate so you have to know what your looking for. The MRI image is more cluttered than the X-Ray although provides more detail, into showing us what the interior of the lung lookes like. In both cases the tumor is easy to identify allowing for the diagnosis of Lung Cancer., It is however slightly easier in the MRI than the X-Ray.