Veterinary Radiography Ch 17

A dorsoventral view of the thorax should be taken at the peak of inspiration because this is when the lungs are fully expanded and the diaphragm is at its lowest position. This allows for a clearer view of the structures within the thorax, such as the heart, lungs, and ribs. Taking the image at the peak of expiration may result in a partially collapsed lung and an incomplete view of the thoracic structures.

A lateral view of the thorax with a horizontal beam is indicated when there is suspicion of fluid or free air in the thorax. This view allows for better visualization and assessment of the thoracic cavity, specifically the lungs and pleural spaces. It can help identify any abnormalities such as pneumothorax or pleural effusion. By using a horizontal beam, the radiologist can obtain a clear image of the thoracic structures and accurately diagnose any potential issues.

During expiration, the diaphragm moves upwards towards the cranial (upper) part of the body, reducing the volume of the thoracic cavity and causing air to be expelled from the lungs. During inspiration, the diaphragm moves downwards towards the caudal (lower) part of the body, increasing the volume of the thoracic cavity and allowing air to enter the lungs. Therefore, it is true that during expiration, the diaphragm is more cranial than during inspiration.

An enema should be given at least 1 hour before radiography because it takes time for the enema solution to reach the colon and adequately cleanse the area. Giving the enema too close to the radiography procedure may not allow enough time for the solution to work effectively, resulting in a suboptimal view of the abdomen. Therefore, it is recommended to administer the enema at least 1 hour before the radiography to ensure a clear and accurate image of the abdomen.

The preferred exposure time for views of the thorax is 1/30 second. This duration allows for capturing clear and detailed images of the thorax without significant motion blur. A shorter exposure time may result in underexposed images, while a longer exposure time may lead to overexposure or motion blur, making it difficult to accurately analyze the thorax.

The ventrodorsal (VD) view allows for better visualization of the caudal mediastinum and accessory lung lobe. This means that by taking a VD view, one can see the area at the back of the chest cavity and the additional lung lobe more clearly. This is an advantage compared to a dorsoventral view, which may not provide as clear of a view of these specific areas.

To achieve a long scale of contrast for an abdominal view, high kVp and low mAs are preferred. High kVp helps to increase the penetration of the X-rays through the body, resulting in a higher contrast between the structures. Low mAs, on the other hand, reduces the amount of radiation exposure to the patient while still maintaining image quality. The combination of high kVp and low mAs helps to produce a clear and detailed image with a long scale of contrast. Contrast media may be used in certain cases to enhance the visualization of specific structures, but it is not the primary factor for achieving a long scale of contrast.

The measurement for a lateral view of the thorax is taken at the caudal border of the scapula.

A right lateral view of the abdomen is preferred over a left lateral view because it allows for better separation of the kidneys. This is important for diagnostic purposes as it provides a clearer view of each kidney individually, making it easier to identify any abnormalities or pathologies.

The field of view for the pharynx must include the lateral canthus of the eye and the third cervical vertebra. The lateral canthus of the eye refers to the outer corner of the eye where the upper and lower eyelids meet. This is important because it helps determine the position and alignment of the pharynx. The third cervical vertebra is also included in the field of view because it is located in the neck region and is closely related to the pharynx.