CT Registry Review March 2010

Viscosity is a measure of a fluid's thickness. It refers to the resistance of a fluid to flow, with high viscosity indicating a thicker fluid that flows more slowly, while low viscosity indicates a thinner fluid that flows more easily. Therefore, thickness is the correct choice as it accurately describes the property being measured.

An injection rate of 4 - 5 ml/sec. will maintain a dense bolus of IV contrast media for a CTA examination and will be tolerated by most patients. This rate is considered optimal as it allows for a sufficient amount of contrast media to be delivered quickly, ensuring clear and accurate imaging results. Additionally, this rate is generally well tolerated by patients without causing discomfort or adverse reactions.

Tungsten's high atomic number means it has a high melting point of approximately 3400 degrees Celsius.

If the mA (milliamperage) of a 2-second brain scan is doubled and all other parameters remain unchanged, the dose of radiation is doubled. This is because the mA is directly proportional to the dose of radiation. When the mA is doubled, the amount of radiation delivered to the brain is also doubled, resulting in an increased dose.

Intrathecal contrast media is injected into the spinal canal to enhance visualization of the spinal cord and nerve roots. Intravenous contrast media is injected into a vein to enhance visualization of blood vessels and tissues. Oral contrast media is ingested to enhance visualization of the gastrointestinal tract. In a CT study of the thoracic spine, there is no need to visualize the gastrointestinal tract, so oral contrast media has no application. Therefore, the correct answer is 3 only.

Noise is responsible for how grainy or speckled a CT image appears. Noise refers to random variations in pixel values that can degrade the image quality. Higher levels of noise can result in a grainy appearance, making it difficult to distinguish fine details in the image. Lower levels of noise are desirable as they improve image clarity and allow for better visualization of structures.

Tube interscan delay time refers to the time between the end of one scan and the start of the next scan during which the tube will cool. This delay is necessary to prevent overheating of the tube and ensure optimal image quality. During this time, the tube is allowed to cool down, reducing the risk of damage and maintaining the functionality of the equipment. By allowing sufficient cooling time, the technologist can ensure accurate and reliable scans.

The result of the bifurcation of the abdominal aorta is the left and right common iliac arteries.

Two faulty detector elements may cause two parallel lines to appear on a localizer image. When the detector elements are faulty, they may produce incorrect readings or fail to detect certain signals, resulting in the appearance of parallel lines on the image. This can distort the accuracy of the localizer image and affect the diagnostic interpretation.

Barium sulfate is the better oral contrast agent for opacifying the distal small intestine. This is because it is not absorbed by the body and provides excellent visualization of the gastrointestinal tract. Ionic and non-ionic iodinated contrast agents are typically used for opacifying other parts of the gastrointestinal tract, but they are not as effective in opacifying the distal small intestine.

A collimator is not a part of the CT tube. The CT tube consists of a filament, rotating anode, and a tungsten target. The collimator is a separate component used to shape and control the X-ray beam emitted by the CT tube. It is responsible for limiting the size and shape of the X-ray beam to ensure accurate imaging and reduce unnecessary radiation exposure.

An x-ray photon must enter the detector chamber in order to be measured. It must also be absorbed by the detector material for it to be detected and recorded. Finally, the x-ray photon must be converted to a measurable event, such as the release of an electron or the generation of an electrical signal. Therefore, all of the given options - 1, 2, and 3 - are correct explanations for the statement.

A pixel refers to a single 2D picture element within the image plane. It represents the smallest unit of information in a digital image, consisting of a single point of color or brightness. Pixels are arranged in a grid pattern to form the complete image and are used to display and represent visual information in various digital devices such as cameras, computer screens, and televisions.

Single emulsion is the most common type of film used for recording CT images. This type of film has a single layer of emulsion, which contains light-sensitive silver halide crystals. When exposed to X-ray radiation, these crystals produce a latent image, which can be developed and fixed to create a visible image. Single emulsion film is widely used in CT imaging due to its high sensitivity and ability to capture detailed images with good contrast. It is also cost-effective and readily available, making it the preferred choice for recording CT images.

A 1024 x 1024 matrix has a total of 1,048,576 pixels. This is because the total number of pixels in a matrix is calculated by multiplying the number of rows (1024) by the number of columns (1024), which gives us 1,048,576. Therefore, the correct answer is "more than 1 million".

A higher value for pitch would stretch the x-ray helix the most. Pitch refers to the distance between each coil of the helix. When the pitch value is increased, the coils become more spread out, causing the helix to stretch. Therefore, the highest value of 1.5 would result in the most stretching of the x-ray helix.

All of the options mentioned (reduced reconstruction FOV, reduced slice thickness, sharp reconstruction filter) would be used in a high resolution study of the temporal bones. A reduced reconstruction FOV helps to focus on a smaller area, increasing the detail and resolution. A reduced slice thickness means thinner slices are taken, allowing for more precise imaging. A sharp reconstruction filter enhances the sharpness and clarity of the images. Combining all three techniques would result in a high resolution study of the temporal bones.

For a CTA exam of lower extremity vasculature to assess atherosclerosis, the coverage should extend from the abdominal aorta to the ankles. This is because atherosclerosis can affect the arteries in the lower extremities, and by imaging the entire length from the abdominal aorta to the ankles, the presence and severity of atherosclerosis can be accurately evaluated. The abdominal aorta is the starting point as it supplies blood to the lower extremities, and the ankles are the end point as they are the most distal part of the lower extremities.

Recalibration of the detector elements would eliminate a ring artifact. Ring artifacts occur when there is a malfunction or inconsistency in the detector elements of a medical imaging system, causing irregularities in the image. By recalibrating the detector elements, any errors or inconsistencies can be corrected, leading to a more accurate and artifact-free image. Decreased matrix, increased mAs, and removal of metal are not directly related to eliminating ring artifacts.

The patient dose in computed tomography (CT) is determined by the product of the tube current (mA) and the exposure time (rotation time). In this case, all other parameters are the same except for the mA and rotation time. The highest patient dose will occur when the product of mA and rotation time is the highest. In this case, the product of mA = 150 and rotation time = 3 seconds is the highest among the given options, resulting in the highest patient dose.

The CT number of water is not affected by any imaging parameter. The CT number represents the density of an object on a CT scan, and water has a known and constant density. Therefore, regardless of the imaging parameters such as kVp, mAs, or slice thickness, the CT number of water remains the same.

To modify a standard CT protocol for children, both the kVp (kilovolt peak) and mAs (milliampere-seconds) should be decreased. Decreasing the kVp helps to reduce radiation dose, as lower energy X-rays are used. Lowering the mAs also reduces the radiation dose, as it decreases the number of X-rays produced during the scan. Decreasing the pitch, which refers to the distance the table moves per rotation of the X-ray tube, is not necessary when modifying a CT protocol for children.

The concentration of iodine, osmolality, and viscosity of an IV contrast agent can all affect patient tolerance. Higher concentrations of iodine can lead to more adverse reactions in patients. Osmolality refers to the number of particles in a solution and a higher osmolality can cause discomfort or adverse reactions. Viscosity, or thickness, of the contrast agent can also impact patient tolerance, as a more viscous agent may be more difficult to inject and cause discomfort. Therefore, all of these characteristics can affect how well a patient tolerates the IV contrast agent.

A localizer scan uses only a single projection. This type of scan is typically used to locate a specific area or region of interest within the body. It provides a localized image rather than a full scan of the entire body. Conventional or serial scans involve multiple projections, while helical scans involve continuous rotation of the scanner during the scan. Therefore, the correct answer is 3 only, as only the localizer scan uses a single projection.

To obtain a diagnostic MIP (Maximum Intensity Projection) of a CTA (Computed Tomography Angiography) exam, the bones in the data set may need to be edited. This is because bones can obstruct the visualization of blood vessels and other structures of interest in the exam. By editing or removing the bones from the data set, a clearer and more accurate MIP can be generated, allowing for better assessment of the blood vessels.

The array processor is a component that is not normally located in the gantry of a modern CT system. The gantry typically houses the x-ray tube, solid-state detectors, and pre-patient collimators. The array processor, on the other hand, is usually located outside the gantry and is responsible for processing the data received from the detectors to generate the final CT image.

The pencil thin section of the x-ray fan beam that strikes a single detector is called a "ray" because a ray refers to a narrow beam of light or energy that travels in a straight line. In the context of x-ray imaging, the fan beam is composed of multiple rays, and each ray represents a path along which the x-ray photons travel from the source to the detector. Therefore, the correct term to describe the thin section of the beam that reaches a single detector is a "ray."

During a helical scan on a third-generation scanner, all of the mentioned components move. The detector elements move to capture the x-ray data, the patient table moves to position the patient correctly, and the x-ray tube moves to emit the x-rays. These movements are coordinated to ensure accurate and comprehensive imaging during the helical scan.

A CT Number Calibration Test performed on a water phantom is expected to yield a result of 0 +/- 3. This means that the CT number measured for the water phantom should be close to 0, with a tolerance of +/- 3. The CT number represents the attenuation of the X-ray beam as it passes through the water, and a result of 0 indicates that the water is accurately calibrated and has the expected density. The tolerance of +/- 3 accounts for any slight variations or uncertainties in the measurement.

The CT dose index (CTDI) and the multiple scan average dose(MSAD) are two ways that the patient dose from a multiple slice CT scanner are measured.

A normal adult typically has a respiratory rate of 12-20 breaths per minute. This range is considered normal as it reflects a healthy breathing pattern. A respiratory rate outside of this range may indicate an underlying medical condition or respiratory distress.

A lateral localizer image should be used to set up axial slices so that they can be angled parallel to the plane of a specific lumbar disk. This is because the lateral orientation allows for visualization of the spine from a side view, which can help determine the exact angle and position of the lumbar disk.

The sharp algorithm with a window width of 2500 and 0.5 to 3 mm slices is the best combination of scanning parameters for evaluating abnormalities within the petrous pyramids of the temporal bones. The sharp algorithm enhances image sharpness and detail, which is important for evaluating small structures like the petrous pyramids. A window width of 2500 allows for a wider range of grayscale values to be displayed, which can help in identifying abnormalities. The slice thickness of 0.5 to 3 mm is ideal for capturing fine details within the temporal bones.

Using no straps or pads so that the patient feels comfortable and unrestricted might increase the possibility of motion artifacts occurring. This is because without proper immobilization, the patient's movements can introduce motion artifacts into the imaging results. Straps and pads are commonly used to secure the patient in a stable position during the procedure, reducing the chances of motion artifacts.

The hardening of an x-ray beam refers to an increase in the energy of the x-ray photons. This can be influenced by several factors. Increasing the kVp (kilovoltage peak) will result in higher energy x-rays and therefore a harder beam. Tissue density also affects the hardening of the beam, as denser tissues will attenuate the x-rays more, resulting in a harder beam. Similarly, tissue thickness plays a role, as thicker tissues will attenuate the x-rays more, leading to a harder beam. Therefore, all of the above factors - kVp, tissue density, and tissue thickness - can affect the hardening of an x-ray beam.

The correct answer is "partial thromboplastin time." Thromboplastin time is a laboratory test that measures the time it takes for blood to clot. However, the term "partial" is necessary to specify that only a partial version of thromboplastin is used in the test. Prothrombin time, on the other hand, measures the time it takes for blood to clot and is not the complete name for the PTT test. Partial prothrombin time is not a recognized laboratory test.

normal adult diastolic pressure = 60 - 80 mm Hg
normal adult systolic pressure = 110 - 140 mm Hg

Long scan times are not more desirable because they average out motion artifacts. In fact, shorter scan times are preferred in CT imaging as they reduce the chances of motion artifacts. Motion artifacts can occur when the patient moves during the scan, leading to blurring or distortion in the images. Therefore, it is important to minimize scan times to obtain clear and accurate CT data.

Partial volume averaging refers to the phenomenon where different tissues within a voxel are averaged together, resulting in a loss of image detail and accuracy. A larger slice thickness means that the voxel encompasses a greater volume of tissue, increasing the likelihood of partial volume averaging. Therefore, slice thickness is responsible for partial volume averaging.

The appropriate range of coverage for a coronal sinus study is from the dorsum sella to the anterior aspect of the frontal sinus. This range includes the region of interest for the study, which is the area from the back of the sella turcica (dorsum sella) to the front of the frontal sinus. This range allows for a comprehensive evaluation of the coronal sinuses and any abnormalities or pathologies that may be present in this area.

To compensate for an increase in apparent image noise caused by reducing the slice thickness, the mAs should be increased. This is because reducing the slice thickness can result in less radiation reaching the detector, leading to increased noise in the image. By increasing the mAs, more radiation is used during the scan, which helps to improve the signal-to-noise ratio and reduce the apparent image noise.

Phonating the letter "e" during a CT exam of the larynx allows for the demonstration of vocal cord mobility. Phonation involves the movement of the vocal cords, and by asking the patient to phonate the letter "e," the examiner can observe how well the vocal cords are able to move and function. This can provide valuable information about the health and function of the larynx, helping to diagnose any potential issues or abnormalities.

The out-of-field artifact is caused by anatomy extending beyond the scan field-of-view. Increasing the scan field-of-view will reduce this by decreasing the likelihood of anatomy extending beyond its boundaries.

Increasing the mAs (milliampere-seconds) would help reduce the apparent image noise when using a thin slice. mAs is a measure of the total amount of radiation used during the exposure. By increasing the mAs, more radiation is used, resulting in a higher signal-to-noise ratio and reduced image noise. This is because the increased mAs provides more photons to create the image, which helps to overcome the noise generated by the detector.

Increasing the pitch in medical imaging refers to increasing the distance between each slice or image taken during a scan. This allows for a faster scan time, as a larger volume of anatomy can be covered in a given time. Additionally, increasing the pitch can also result in a higher radiation dose to the patient, as the scanner is capturing images at a faster rate. Therefore, the correct answer is 2 & 3.

Multi-row detector CT scanners have multiple detector arrays, and all of these arrays may or may not be used depending on the specific scanning requirements. Additionally, the attenuation information from adjacent detector arrays can be added together to generate thicker slices, allowing for better visualization of structures. Furthermore, the size of the detector arrays along the z-direction may be different, providing flexibility in scanning different anatomical regions. Therefore, all of the statements mentioned in the options are true regarding multi-row detector CT scanners.

# of Rows X # of columns = total # of pixels

A smooth, or low-pass, reconstruction filter is typically not selected for an internal auditory canals exam because it is not necessary to filter out high-frequency noise or artifacts in this specific type of examination. The internal auditory canals are part of the ear and are responsible for transmitting sound and maintaining balance. Therefore, a smooth reconstruction filter, which is used to enhance low-frequency signals and remove high-frequency noise, is not needed for this particular exam.

If the patient history was taken at the time of scheduling, it means that the medical staff already knows that the patient is claustrophobic. Therefore, the patient can arrive for the scan prepared with a prescription sedative to help them manage their anxiety during the procedure. This is the only statement that is true in this context.

CPR must be administered to a cardiac arrest victim within a maximum of 4 minutes before there is a risk of brain damage. When the heart stops pumping blood, the brain is deprived of oxygen, and brain cells can start to die within minutes. CPR helps to maintain blood flow and deliver oxygen to the brain until professional medical help arrives. The sooner CPR is started, the better the chances of preventing brain damage and increasing the chances of survival.

The ARRT Standard of Ethics is made up of two components: the Code of Ethics and the Rules of Ethics. The Code of Ethics serves as a conduct guideline, providing principles and standards that radiologic technologists should adhere to in their professional practice. The Rules of Ethics, on the other hand, are enforceable regulations that further specify the expectations and requirements for ethical behavior. Together, these two components form a comprehensive framework for maintaining ethical standards in the field of radiologic technology.

Exams to rule out aortic dissection, hilar mass, and lymphoma would indicate the use of IV contrast media in the chest. This means that all three conditions require imaging exams that involve the administration of IV contrast media to help visualize and identify any abnormalities or potential diseases in the chest area. Therefore, all of the above options (1, 2, and 3) are correct as they all require the use of IV contrast media for diagnosis.

An indication for IV contrast injection is to rule out meningioma. Meningioma is a type of brain tumor that arises from the meninges, the protective membranes surrounding the brain and spinal cord. IV contrast injection is often used in imaging tests such as CT scans or MRI scans to enhance the visibility of certain structures or abnormalities, including tumors. By injecting contrast dye into the bloodstream, the tumor can be better visualized and distinguished from other conditions such as Grave's disease, mastoiditis, or sinusitis.

When a contrast agent is injected directly into the joint space, it is known as intraarticular contrast. This method is commonly used in medical imaging, such as arthrography, to enhance the visibility of structures within the joint. By injecting the contrast agent into the joint, it allows for better visualization and evaluation of the joint and surrounding structures, helping to diagnose and treat various joint-related conditions.

A window setting with a wider window width allows for a greater range of Hounsfield units to be displayed. This means that more shades of gray can be seen, providing better tissue differentiation. The window level determines the midpoint of the range, with higher values shifting the range towards brighter shades and lower values shifting it towards darker shades. In this case, a window width of 300 and a window level of 40 would provide a good balance between a wide range of gray shades and a midpoint that is suitable for differentiating soft tissues in the abdomen.

Barium sulfate solutions used in CT are less concentrated than those used in conventional radiography. This is because in CT, the goal is to enhance the contrast between different tissues and structures in the body, while minimizing the radiation dose to the patient. Therefore, a lower concentration of barium sulfate is used in CT to achieve the desired contrast without overexposing the patient to radiation. In conventional radiography, higher concentrations of barium sulfate may be used to obtain clearer images.

The number of electrons that flow from the cathode to the anode in the tube is controlled by the milliamperage (mA). The milliamperage determines the strength of the current passing through the tube, which directly affects the number of electrons flowing. Higher milliamperage results in more electrons flowing, while lower milliamperage reduces the number of electrons. Therefore, the correct answer is mA.

Solid state detectors are the detector type used on most CT scanners today, making statement 1 true. They can be used in both third-generation and fourth-generation CT systems, making statement 2 true. X-ray photons cause the detectors to generate a flash of light, making statement 3 true. Therefore, all the statements are true, making the correct answer "all the above".

During a scan, the patient table may move continuously. This movement is necessary to ensure that each slice of the scan is completed accurately. However, once the initial positioning is done, the table remains stationary throughout the entire patient exam. The continuous movement of the table allows for a thorough and precise scan, while the stationary position afterwards ensures patient safety and stability.

The correct answer is "all of the above". This means that all three statements are true. Statement 1 states that the amplified electrical signal obtained from the detectors must be digitized, which is true because digital CT scanners convert analog signals into digital form for processing. Statement 2 states that digital CT images are numerical representations of cross-sectional anatomy, which is true because digital CT scanners produce images by collecting numerical data from multiple cross-sectional slices. Statement 3 states that digital signals may be formed by sampling analog signals at discrete time intervals, which is true because digital signals are created by taking discrete samples of an analog signal at specific time intervals.

During a post-contrast CT study of the neck, the administration of contrast agent enhances the visibility of blood vessels and lesions due to increased blood flow and vascularity. However, lymph nodes do not enhance significantly during this study because they lack a high vascularity compared to blood vessels and lesions. Therefore, lymph nodes would not enhance during the first several minutes of a post-contrast CT study of the neck.

Hives are not a typical adverse reaction to oral contrast media used in CT. Oral contrast media can cause adverse reactions such as abdominal cramping, diarrhea, and flatulence. However, hives, which are itchy, raised welts on the skin, are not commonly associated with the use of oral contrast media.

The correct answer is that signed consent forms are not required by law in every state. This means that there are some states where it is not legally mandatory for patients to sign consent forms. The other options listed (permission to administer contrast, permission to perform surgical procedure, permission to administer sedation) are not the correct answer because they do not address the requirement of signed consent forms in every state.

Filtered back projection is the mathematical process used by single-row detectors scanners to reconstruct CT images from raw data. This technique involves filtering the raw data and then back projecting it onto the image plane to create a two-dimensional image. It is a commonly used method in CT imaging as it allows for the reconstruction of high-quality images by accounting for the attenuation of X-ray beams as they pass through the body. The other options, integration of the area under the curve, the Fourier transform, and weighted averaging, are not the specific processes used in CT image reconstruction.

In order to obtain 5 mm slices with 1 mm of overlap on a conventional CT scan, the table increment should be 4 mm. This means that after each slice is taken, the table would move 4 mm to position the next slice for imaging. This allows for the desired overlap between slices and ensures that the entire region of interest is captured accurately.

The correct answer is 1 & 3. This means that the service engineer should be notified about both a consistent circle on the images (option 1) and frequent bad streaks throughout the entire image (option 3). These issues could indicate a problem with the imaging equipment that needs to be addressed by the service engineer. Option 2, which refers to frequent bad streaks on the inferior slices of head scans, is not mentioned as something that should be brought to the service engineer's attention.

An edge gradient artifact is a streak artifact that occurs when there is a high spatial frequency interface between tissues with a significant difference in density. This artifact is caused by the abrupt change in density at the tissue interface, resulting in streaks or lines on the image.

The correct answer is the collision of the electron beam with the tungsten target on the tube anode. When the electron beam strikes the tungsten target, it transfers its kinetic energy to the target, causing it to heat up. This heat is then dissipated through the CT tube, resulting in the enormous heat buildup.

A 10 mm slice from a 20 slice study would display the greatest amount of partial volume artifact. This is because a thicker slice (10 mm) has a higher chance of including multiple tissues with different densities within it, leading to partial volume averaging. Additionally, a 20 slice study may not have enough slices to adequately capture the details of the anatomy, resulting in more pronounced partial volume artifacts.

A window width of 140 and a window level of 60 provide the best tissue differentiation within the liver. A narrower window width allows for better contrast between different densities of tissues, while a higher window level helps to highlight the specific range of densities within the liver. This combination allows for optimal visualization and differentiation of liver tissue.

Multi-row detector scanners employ third-generation technology.

MIP stands for Maximum Intensity Projection. In this technique, the highest pixel values from a stack of CTA (Computed Tomography Angiography) images are projected along many "rays". This allows for the visualization of the blood vessels and other structures with the highest intensity, providing a clearer and more detailed image.

Pixel size = reconstruction FOV/matrix. Pixel size =320 mm/512.

Decreasing the distance from the x-ray tube to the patient actually increases the radiation dose to the patient. The closer the patient is to the x-ray tube, the higher the radiation dose received. Therefore, decreasing the distance does not minimize the radiation dose to the patient.

The cephalic vein is a less desirable site for injection than the basilic vein because the flow of blood may be impeded when the patient's arms are raised. This can make it difficult to administer medication or draw blood effectively. In contrast, the basilic vein is not affected by arm movement, making it a more suitable choice for injections.

Decreasing the slice thickness would reduce the partial volume effect. The partial volume effect occurs when a voxel contains a mixture of different tissues, causing blurring and loss of detail in the image. By decreasing the slice thickness, the voxel size becomes smaller, reducing the likelihood of containing multiple tissues and improving spatial resolution. This allows for better differentiation and visualization of structures, reducing the partial volume effect.

Barium sulfate oral contrast media would be selected instead of iodinated oral contrast media because it stays more dense in the distal GI tract. This means that it provides better visualization of the lower gastrointestinal tract, allowing for more accurate diagnosis of any abnormalities or conditions in that area. Additionally, the use of barium sulfate may be preferred in trauma patients who may have a perforated bowel, as it is less likely to leak into the abdominal cavity compared to iodinated contrast media.

Spatial resolution is a measure of the smallest objects able to be resolved. Spatial resolution = FOV/matrix. Spatial resolution = 240 mm/512.

infant = 100 - 180
child = 95 - 110
adult = 70 - 100
athletic adult = 45 - 60

Osmolality is a measure of the concentration of molecular particles in a solution. It quantifies the number of solute particles present in a unit of solvent, regardless of their size or charge. This measurement is important in medical and biological fields as it helps determine the osmotic pressure and the effects of a solution on cells and tissues.

The appropriate care to give to a patient with diabetes includes using LOCM if IV contrast media is required and advising the patient to resume the use of Metformin 48 hours after IV contrast administration only after kidney function has been reassessed and determined to be normal. This ensures that the patient's kidney function is not compromised and that the use of Metformin is safe.

The typical scan delay after the initiation of injection of contrast media for studies of the liver is 65 to 75 seconds. This delay allows the contrast media to circulate through the liver and enhance the visualization of the blood vessels and liver parenchyma. It gives enough time for the contrast to reach the desired concentration in the liver, ensuring optimal image quality for diagnostic purposes.

Collimation is the process of narrowing down the beam of x-rays to a specific area of interest. This is typically achieved by physically blocking the x-rays using collimators, which are devices that have lead plates with small apertures. These lead plates absorb or block the x-rays that are not needed for the scan, resulting in a more focused and accurate image. By physically blocking the x-rays, collimation helps to reduce scatter radiation and improve image quality. It does not involve electrically blocking x-rays or limiting the energy of the photons.

The correct answer is the operator's console. The operator's console is where most of the commands from the technologist are received. This is where the technologist interacts with the system and inputs commands for various operations. The operator's console acts as a control panel for the technologist to monitor and manage the system effectively.

Retrospective reconstruction is a technique applied to the raw data after the primary reconstruction has already been accomplished. It allows for additional image manipulations and adjustments to be made, such as changing the slice thickness or orientation, without having to acquire new data. This technique is often used in medical imaging to improve the quality and diagnostic value of the images.

2.4cm = 24mm/2 mm slice thickness = 12 slices

The correct answer is "bolus, non-equilibrium, equilibrium." This is the correct order in which the phases of IV contrast enhancement occur. First, the contrast agent is injected as a bolus, which quickly fills the blood vessels. Then, the non-equilibrium phase occurs, where the contrast agent is distributed throughout the body and organs. Finally, the equilibrium phase is reached, where the contrast agent is evenly distributed and the concentration remains constant.

If the patient's arms are placed at their sides during a chest exam with a scan field-of-view of 33 cm, two possible occurrences may happen. The first is beam hardening, which is a type of artifact caused by the attenuation of the X-ray beam as it passes through different materials. This can result in streaks or dark bands on the image. The second occurrence is an out-of-field artifact, which happens when the area outside the scan field-of-view affects the image quality. This can include structures or objects that are not within the intended area of examination.

A common patient reaction to IV contrast media includes warmth at the injection site, headache, and nausea. These symptoms are often experienced by patients after receiving IV contrast media.

An increase in kVp will result in hardening of an x-ray beam because higher kVp values lead to higher energy photons, which can penetrate tissues more effectively. Similarly, an increase in tissue density will result in hardening of the x-ray beam because denser tissues attenuate the beam less, allowing more photons to reach the detector. Additionally, an increase in tissue thickness will also result in hardening of the x-ray beam because thicker tissues attenuate the beam more, reducing the number of photons that reach the detector. Therefore, all of the given options (1, 2, and 3) contribute to the hardening of an x-ray beam.

X-ray photons can be produced through all three mechanisms mentioned. When a fast-moving electron collides with an atomic nucleus, it can cause the emission of X-ray photons. Similarly, when a fast-moving electron collides with an electron within an atom and ejects it, X-ray photons can be generated. Finally, when a fast-moving electron passes close to an atomic nucleus, it can also result in the production of X-ray photons. Therefore, all three options are correct and contribute to the generation of X-ray photons.