Radtech Simulation Examination 9

The Licensee shall reduce the dose that an individual may be allowed to receive in the current year by the amount of occupational dose received while employed by any other person or facility.

PET (Positron Emission Tomography) is considered the gold standard investigation for recurrent gastrointestinal stromal tumors (GISTs). PET scans use a radioactive tracer to detect cellular activity and can identify areas of abnormal metabolic activity, helping to determine the presence and extent of recurrent tumors. This imaging technique is particularly useful in detecting small lesions, evaluating treatment response, and guiding further management decisions. MRI, MIBG, and USG are also imaging modalities used in the evaluation of GISTs, but PET has shown to be more accurate and sensitive in detecting recurrent disease.

Shutting power to the PDU may be required for life threatening situations such as:
Fire in the computer room, fire, sparks, loud noises emanating from the scan room, flooding or sprinkling system goes off, and catastrophic equipment failure. These reasons should be life threatening. It is important to remember that pressing the emergency stop button shuts the power to the scanner to but the magnetic field is still active.

The distal duodenum showing a cap-like appearance is false regarding contrast radiography. Contrast radiography is a diagnostic imaging technique that uses a contrast agent to visualize the gastrointestinal tract. In contrast radiography, the jejunum typically appears feathery due to its numerous circular folds called plicae circulares. The ileum, on the other hand, appears featureless as it lacks prominent circular folds. The colon shows asymmetric haustrae, which are pouch-like segments. However, the distal duodenum does not exhibit a cap-like appearance in contrast radiography.

The correct answer is 60 because x-ray timers calibrated in impulses measure the number of impulses that occur in a second. Therefore, there are 60 impulses in a second.

A calcium tungstate screen is a type of intensifying screen that emits blue light. It is used with film that is sensitive to blue light. This screen contains calcium tungstate phosphors, which emit light when exposed to radiation. The blue light emitted by the screen helps to enhance the image quality and reduce the amount of radiation required for exposure.

The magnetic field can extend many feet from the inner bore of the magnet. Rooms are shielded to contain the field as much as possible. Remember the magnet is always on even when a scan is not initiated. The main magnetic field of a 3T system is 60,000 times the earth's magnet field. We must also limit the items that go into the scan room to non-ferrous metals.

Small items like paper clips or hair pins can have a velocity of about 40mph in a 3T environment. Larger objects have even higher velocities and have become fatal. Many types of clinical equipment are ferromagnetic and should never be brought into the scan room. If there is any question a handheld magnet can be used to test if an object is ferromagnetic or not.

We have a Siemens 3T Trio Scanner. 3T machines are double the strength of 1.5T machines. It is important to remember that if an object/implant has been cleared for a 1.5T machine it does not mean it is ok for a 3T machine. Further research must be done.

Size #2 is considered to be the standard adult film size.

In an unrestricted area, there is no specific level of radiation that requires a sign to be posted. This means that the radiation levels in this area are considered to be safe and do not pose a significant risk to individuals. Therefore, there is no need to post a sign indicating radiation levels in an unrestricted area.

Checking constancy is necessary to ensure that something remains consistent over time. At installation, it is important to verify that the constancy is set correctly. Checking daily is necessary because constancy can be affected by various factors such as wear and tear, environmental conditions, or other changes that may occur on a daily basis. Regular daily checks help to identify any deviations or issues that may arise and allow for prompt corrective actions. Therefore, checking at installation and daily ensures that constancy is continuously monitored and maintained.

Samarium 135 is not a pure beta emitter because it undergoes both beta decay and gamma decay. Beta decay involves the emission of beta particles (electrons or positrons) from the nucleus, while gamma decay involves the emission of gamma rays, which are high-energy photons. Yttrium-90, Phosphorus-32, and Strontium-89 are pure beta emitters as they only undergo beta decay without any accompanying gamma decay.

Serous cystadenoma is a benign tumor of the pancreas that often presents with a spongy appearance on imaging. It can also show central sunburst calcification, which is a characteristic feature of this tumor. This appearance is not typically seen in pancreatic adenocarcinoma, mucinous cystadenocarcinoma, or somatostatinoma.

Ionization occurs when an electron is displaced from its orbit. This process can happen when an atom or molecule absorbs enough energy to remove an electron from its outer shell, resulting in the formation of charged particles called ions. This phenomenon is commonly observed in various physical and chemical processes, such as in the formation of plasma, radiation interactions, and chemical reactions. Cell death, penetration of photons, and conversion of radiant energy to heat are not directly related to ionization.

Alpha rays are particulate radiation, travel slowly and has more LET. This will lead to more radiation damage to the cells

Gamma rays are an example of electromagnetic radiation because they are a form of high-energy electromagnetic waves. They have the shortest wavelength and highest frequency among the electromagnetic spectrum. Gamma rays are produced by nuclear reactions and radioactive decay, and they can penetrate through most materials. They are used in various fields including medicine, industry, and research.

The intensity of the beam is affected by the kilovolt peak, milliamperage, exposure time, and focal film distance. Kilovolt peak determines the energy of the X-ray beam, milliamperage controls the quantity of X-rays produced, exposure time determines the duration of X-ray exposure, and focal film distance affects the divergence and intensity of the X-ray beam. Therefore, all of these factors affect the intensity of the beam.

The central dot sign is a radiological finding that is seen in Caroli Disease. Caroli Disease is a rare congenital disorder characterized by dilatation of the intrahepatic bile ducts. The central dot sign refers to a small central dot or linear density within a larger low-density lesion on imaging studies, such as ultrasound or CT scan. This sign is caused by the presence of a small central fibrous core within the dilated bile duct. Therefore, the correct answer is Caroli Disease.

X-rays with long wavelengths are most likely to be absorbed by the skin. This is because longer wavelength x-rays have lower energy levels, making them more easily absorbed by the skin tissue. In contrast, x-rays with short wavelengths have higher energy levels and are more likely to penetrate through the skin and interact with deeper tissues. Aluminum filtered rays, high energy waves, and sonic waves are not specifically mentioned as being absorbed by the skin, so they are not the correct answer.

Breastfeeding does not need to be stopped for Gallium and Indium. The answer "1-4 weeks" is incorrect as it suggests that breastfeeding needs to be stopped for a specific duration, which is not necessary for these substances.

Protein-losing enteropathy is a condition characterized by the abnormal loss of protein from the intestines. It can be diagnosed using various imaging techniques and tests. Tc 99 Sotisumab is not used for the diagnosis of protein-losing enteropathy. Therefore, it is the correct answer as it is the exception among the given options.

In an alternating current (AC) system, the polarity is reversed multiple times per second. This is because AC current constantly changes direction, flowing first in one direction and then in the opposite direction. The frequency of these reversals is measured in hertz (Hz), which represents the number of cycles per second. Therefore, the correct answer is 60, indicating that the polarity is reversed 60 times per second in a dental x-ray machine operating on an alternating current.

An intentional quench is done in an emergency to run the magnetic field to zero. This is done in extreme emergencies only (ex- a projectile that is pinning a patient against the magnet, injuring them).

In left ventricular failure, there is an inadequate pumping of blood from the left ventricle, leading to a buildup of fluid in the lungs. This results in various characteristic findings on imaging. Kerley B lines are horizontal lines seen on chest X-rays, indicating fluid in the interlobular septa of the lungs. Increased pulmonary capillary wedge pressure is a measure of the pressure in the left atrium and reflects fluid backup in the lungs. Increased vascularity in the upper lobes is a compensatory mechanism due to the redistribution of blood flow. Oligaemic lung fields, on the other hand, refer to decreased blood flow to the lungs, which is not typically seen in left ventricular failure.

Contrast refers to the difference in degrees of blackness on a radiograph. It is a measure of the variation between the light and dark areas of the image. Higher contrast indicates a greater difference in blackness, while lower contrast means there is less variation. This term is used to describe the clarity and sharpness of the image, as well as the ability to distinguish between different structures or tissues.

Flexible cassettes are used in some panoramic units. This suggests that not all panoramic units utilize flexible cassettes. The reason for this could be the potential issue of cracking of the emulsion. It is possible that some panoramic units have found alternative methods or materials to prevent this cracking, while others still rely on traditional cassettes.

Equivalent to 5-10 mGy/hr/mCi

When a patient crosses their legs or intertwines their fingers a circuit is formed and it is more likely to cause peripheral nerve stimulation.

The given ultrasound findings of diffuse wall thickening with a hyperechoic nodule at the neck, along with comet tail artifacts, are suggestive of adenomyomatosis. Adenomyomatosis is a benign condition characterized by hyperplastic changes in the gallbladder wall, resulting in the formation of small outpouchings called Rokitansky-Aschoff sinuses. The hyperechoic nodule represents cholesterol deposits within these sinuses, and the comet tail artifacts are caused by the reflection of sound waves from the cholesterol crystals. Adenocarcinoma of the gallbladder would typically present with focal wall thickening and may have associated features such as gallbladder wall invasion or lymphadenopathy. Xanthogranulomatous cholecystitis and porcelain gall bladder would also have distinct ultrasound findings.

Breastfeeding should be stopped for 0-24 hours after receiving Tc-99m. This is because Tc-99m is a radioactive material used in medical imaging, and it is important to minimize the exposure of the infant to radiation. By stopping breastfeeding for this period, the mother can ensure that the radioactive material is cleared from her body, reducing the risk of radiation exposure to the baby.

Employers must inform their radiation workers of their radiation exposure levels annually. This is important to ensure that workers are aware of their exposure and can take necessary precautions to protect themselves from the potential health risks associated with radiation. Annual notification allows workers to stay informed about their exposure levels and make any necessary adjustments in their work practices or safety measures. Regular communication about radiation exposure levels is crucial for maintaining a safe working environment and ensuring the well-being of radiation workers.

A periapical radiograph is a type of intraoral radiograph that shows the entire tooth from the crown to the root, as well as the surrounding bone and tissues. It is commonly used to diagnose and monitor dental conditions such as tooth decay, infections, and bone loss. This type of radiograph is taken by placing the film or sensor near the tooth of interest and capturing an image. It provides detailed information about the tooth structure and can help in determining the need for treatments such as root canal therapy or extraction.

Breastfeeding does not need to be stopped for F-18, as there are no specific reasons mentioned in the question that would require the cessation of breastfeeding. The other options provided, such as 0-24 hrs, 1-4 weeks, and stopping for the remainder of pregnancy, do not apply to the situation described in the question. Therefore, the correct answer is that there is no need to stop breastfeeding for F-18.

The maximum permissible whole body dose to an occupationally exposed individual for one year is 5000 mRem, while the maximum permissible dose for a declared pregnant worker for the 9 months of gestation is 500 mRem. This means that the allowed radiation exposure for a pregnant worker is significantly lower than that for a non-pregnant individual. This is because radiation can potentially harm the developing fetus, so extra precautions are taken to ensure the safety of pregnant workers.

The correct answer is 15 Rem. Occupational dose limits are set to ensure that radiation exposure remains within safe levels for workers. The lens of the eye is particularly sensitive to radiation, and exposure to high levels can lead to cataracts. Therefore, a limit of 15 Rem is set to protect the lens of the eye from harmful radiation effects.

A long FFD (focus-to-film distance) is desirable because it means that the central rays of the primary beam are less divergent. This means that the X-ray beam is more focused and concentrated, resulting in better image quality and less scatter radiation. A less divergent beam allows for greater detail and clarity in the resulting image.

In recent years, there has been a growing concern about the potential of ionizing radiation used in dentistry to induce cancer in patients. This is because ionizing radiation has the ability to damage DNA and other cellular structures, which can lead to the development of cancerous cells. While the other options, such as somatic damage to the patient, occupational exposure of dental workers, genetic damage to patients, and its contribution to background radiation, are also important considerations, the focus has been primarily on the risk of cancer induction in patients due to the long-term consequences it can have on their health.

Translation describes the force that attracts ferrous objects to the center of the magnetic field. It is sometimes referred to as the projectile effect. Rotation is the term that relates to the force of the North and South poles and the orientation of the scanner’s magnetic field. Ferrous objects will attempt to align their long axes with this orientation and will rotate until they are aligned with the magnetic field.

Scatter radiation refers to the radiation that is deflected from its original path due to interaction with matter. In medical imaging, scatter radiation can cause a blurred image and decrease image quality. The use of a kilovolt peak between 45-65 helps to minimize scatter radiation by optimizing the energy of the X-ray beam. Therefore, the correct answer is scatter radiation.

The statement is false because nonscreen film is not routinely used in extraoral radiography. In extraoral radiography, screen film is commonly used, which requires the use of intensifying screens to enhance the image quality. Nonscreen film, on the other hand, does not require intensifying screens and is typically used in intraoral radiography.

Breastfeeding should be stopped for the remainder of pregnancy when the I-131 dose is greater than 2 uCi. This is because I-131 is a radioactive substance used in medical treatments, and it can be harmful to the developing fetus. Stopping breastfeeding during pregnancy helps to avoid exposing the fetus to the radioactive substance, ensuring the safety of both the mother and the baby.

The correct answer is 5 Rem and 50 Rem. Occupational dose limits refer to the maximum amount of radiation exposure that a person can receive while working in a radiation-related occupation. The limits for whole body and extremities are different because different parts of the body have different sensitivities to radiation. The limit for whole body exposure is set at 5 Rem, while the limit for extremity exposure is set at 50 Rem. This means that a person can be exposed to up to 5 Rem of radiation throughout their entire body, but up to 50 Rem of radiation in a specific extremity, such as a hand or foot.

Dissipation of the absorbed RF energy is described in terms of Specific Absorption Rate (SAR), measured in watts/kg. SAR is calculated by the patient’s weight and the expected increase in body temperature for each imaging pulse sequence. The scanner will calculate how much heat the patient will be absorbed if it is too high the scan will not run.

The statement "if less film density is needed on the duplicate radiograph the exposure time is shortened" is false concerning film duplication. In reality, if less film density is desired on the duplicate radiograph, the exposure time should be lengthened, not shortened. This allows for less light to reach the film, resulting in a lighter image with lower density.

Cathode rays are an example of particulate radiation. They are streams of electrons emitted from the cathode in a vacuum tube. Cathode rays have mass and charge, and they can be deflected by electric and magnetic fields. Therefore, they are considered particulate radiation. Gamma rays and x-rays, on the other hand, are forms of electromagnetic radiation and do not consist of particles. Therefore, they are not examples of particulate radiation.

The function of a step-down transformer in the construction of an x-ray tube is to convert the line current of 110 volts to less than 10 milliamperes. This is necessary because x-ray tubes require high voltage but low current to generate the necessary energy for producing x-rays. The step-down transformer reduces the voltage while increasing the current to achieve the desired output.

Heat deposition and nerve stimulation are hazards of a varying magnetic field.

The use of a 16-inch cylinder in the paralleling technique helps to avoid magnification of the image. Magnification occurs when the object being imaged appears larger than its actual size due to the distance between the object and the image receptor. By using a longer cylinder, the object can be positioned further away from the image receptor, reducing the magnification effect and providing a more accurate representation of the object's size and dimensions.

The intensity of a beam of radiation decreases with distance according to the inverse square law. This means that if the intensity is 12 at a point 12 inches from the target, the intensity at double the distance, 24 inches, would be 12 divided by 2 squared, which is 3.