Recognizing and Correcting Positioning Errors in Veterinary Radiography

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Patient rotation around the long axis is a primary positioning error, identifiable by loss of symmetry in paired structures like ribs or vertebral pedicles, leading to asymmetric magnification and potential misinterpretation of organ size or joint pathology.
• Obliquity, where the X-ray beam is not perpendicular to the anatomic plane, causes elongation or foreshortening of structures, potentially mimicking or masking fractures, joint space narrowing, or organomegaly.
• Improper collimation, with fields larger than the anatomy of interest, increases scatter radiation, reduces contrast, and necessitates repeat exposures, thereby increasing the radiation burden on the patient and personnel.
• Repeat radiography is mandated when rotation prevents answering the clinical question; for instance, a rotated thoracic radiograph obscuring the cranial mediastinum in suspected lymphoma requires re-imaging.
• Radiation safety is intrinsically linked to image quality; proper positioning and collimation minimize repeat exposures, directly reducing cumulative radiation dose to the patient and staff.
• Species-specific thoracic conformation (e.g., deep-chested dogs vs. horses) necessitates distinct approaches to assessing rotation, impacting the interpretation of cardiac silhouette symmetry and pulmonary vasculature.

Radiographic positioning errors are among the most common causes of non-diagnostic studies in veterinary practice. A rotated patient, oblique projection, or improperly collimated field can obscure pathology, simulate disease that is not present, and force repeat exposures that increase radiation burden and prolong anesthesia or sedation. This article provides a systematic framework for recognizing positioning errors across species, understanding their effects on image interpretation, and applying corrective techniques at the table.

The content is written for practicing veterinarians who perform and interpret their own radiographs, as well as those who supervise technical staff. It addresses the diagnostic reasoning required to distinguish a positioning artifact from a genuine lesion, and it offers practical decision criteria for deciding whether a study must be repeated. The principles apply to dogs, cats, horses, and production animals, with species-specific considerations noted where they materially change the approach.

Radiographic interpretation depends on the assumption that the image represents a true anatomic projection. When that assumption fails, every subsequent diagnostic conclusion is compromised. The ability to recognize subtle rotation on a thoracic radiograph, to detect obliquity on a pelvic study, or to identify incomplete collimation on a dental film is a core clinical skill that directly affects patient outcomes. This article builds that skill from first principles.

At a Glance

The Physics and Geometry of Positioning Errors

Radiographic image formation is a geometric projection. The x-ray beam originates from a focal spot, passes through the patient, and exposes a receptor. The resulting image is a two-dimensional representation of a three-dimensional object, and its fidelity depends on the spatial relationship between the beam, the patient, and the receptor. When the patient is positioned so that the beam passes perpendicular to the anatomic plane of interest and the receptor is parallel to that plane, the image is a faithful representation. Any deviation from this geometry introduces distortion.

Rotation occurs when the patient's long axis is twisted relative to the beam direction. The effect is asymmetric magnification and superimposition. Structures on the side closer to the source appear larger, while structures on the side closer to the receptor appear smaller. Paired structures that should superimpose, such as the ribs over the cardiac silhouette or the femoral heads within the acetabula, separate and become asymmetric. The degree of visible asymmetry depends on the amount of rotation and the inherent symmetry of the region.

Obliquity is a related but distinct error. In obliquity, the beam is angled relative to the anatomic plane instead of the patient being twisted. The result is elongation or foreshortening of structures depending on the angle of incidence. A structure oriented obliquely to the beam appears longer or shorter than its true dimension, which can mimic or mask fractures, joint space narrowing, or organomegaly.

The diagnostic consequences of these errors are substantial. A rotated thoracic radiograph can make the cardiac silhouette appear enlarged on one side and small on the other, leading to a false diagnosis of cardiomegaly or a missed pericardial effusion. A rotated pelvic radiograph can make one hip appear dysplastic while the contralateral hip appears normal. These are not theoretical concerns, they are common reasons for referral of images to specialty review.

Recognizing Rotation on Thoracic Radiographs

The thorax is the most frequently radiographed region in small animal practice, and it is also the region where rotation is most commonly missed. The key to recognizing rotation is the evaluation of symmetry in paired structures that are visible on the lateral and dorsoventral or ventrodorsal projections.

On the lateral projection, the ribs should superimpose symmetrically over the cardiac silhouette. The dorsal spinous processes of the thoracic vertebrae should be visible as a single line, and the sternum should align with the spine. When the patient is rotated, the ribs on one side move cranially or caudally relative to the other side, and the cardiac silhouette appears widened or narrowed depending on the direction of rotation. The vertebral canal should appear as a single radiolucent channel, rotation causes the pedicles to separate and the canal to appear doubled.

On the dorsoventral or ventrodorsal projection, the sternum should lie directly over the spine, and the ribs should be symmetric in their curvature and spacing. The cardiac silhouette should be centered, and the pulmonary vasculature should be symmetric. Rotation is detected by comparing the distance from the spine to the lateral thoracic wall on each side, these distances should be equal. A difference of more than a few millimeters indicates rotation sufficient to affect interpretation.

The sternal recumbent position used in many practices introduces a specific challenge. In sternal recumbency, the patient's weight can cause the thorax to roll to one side, particularly in deep-chested breeds. The radiographer must actively support the sternum to maintain a true lateral position. In horses, the standing lateral projection requires the beam to be horizontal and the cassette to be positioned perpendicular to the beam, rotation is assessed by the superimposition of the ribs over the cardiac silhouette, but the large thoracic volume makes subtle rotation difficult to detect.

Recognizing Rotation on Abdominal and Pelvic Radiographs

The abdomen presents different landmarks for assessing rotation. On the lateral projection, the lumbar vertebrae should be superimposed, with the spinous processes forming a single line and the transverse processes symmetric. The kidneys should be visible as paired structures that are symmetric in size and position. Rotation causes one kidney to appear larger and more ventral while the other appears smaller and more dorsal, which can mimic renal asymmetry or a mass effect.

On the ventrodorsal projection, the pelvis provides the most reliable landmarks. The ilial wings should be symmetric, and the obturator foramina should be equal in size and shape. The femoral heads should sit symmetrically within the acetabula. Rotation is detected by comparing the width of the obturator foramina, the foramen on the side toward which the patient is rotated appears smaller and more elongated. This sign is particularly useful in hip dysplasia screening, where even mild rotation can alter the measured angles used for classification.

The PennHIP and Orthopedic Foundation for Animals (OFA) protocols for hip evaluation require strict positioning standards because rotation directly affects the distraction and compression indices. A rotated pelvis invalidates the study for these purposes, and the image must be repeated. The same principle applies to the evaluation of the lumbosacral junction, where rotation can simulate or mask spondylosis or discospondylitis.

Collimation Errors and Their Consequences

Improper collimation is the most common positioning error in veterinary radiography, and it is also the most easily corrected. Collimation serves two purposes: it limits the field of radiation to the anatomy of interest, and it reduces scatter radiation that degrades image contrast. When the field is too large, scatter increases, the image appears gray and low in contrast, and the patient receives unnecessary radiation. When the field is too small, anatomy is excluded and the study may be non-diagnostic.

The collimation field should extend approximately one to two centimeters beyond the margins of the anatomy of interest. For a thoracic study, the field should include the entire thorax from the thoracic inlet to the caudal lung margin, with the cranial border at the first ribs and the caudal border at the diaphragm. For an abdominal study, the field should extend from the diaphragm to the pubis. Dental radiography requires even tighter collimation, with the field limited to the tooth and its immediate surroundings to maximize detail and minimize scatter.

The radiation safety implications of collimation are direct. A properly collimated study delivers less radiation to the patient and to personnel than a study with a wide field, and it produces a higher quality image that is more likely to be diagnostic on the first attempt. The American College of Veterinary Radiology emphasizes that radiation safety is inseparable from image quality, a study that must be repeated because of poor collimation doubles the radiation burden without adding diagnostic information.

Systematic Assessment of the Rotated Radiograph

When a radiograph arrives with suspected rotation, the first step is to determine whether the error compromises the diagnostic question. A mildly rotated thoracic study may still permit evaluation of the pulmonary vasculature, while the same degree of rotation can render cardiac size assessment unreliable. The assessment sequence proceeds from global to local: confirm patient identification and study labeling, evaluate overall density and exposure, identify the projection, then assess symmetry using the anatomic landmarks appropriate to the region.

For thoracic radiographs, compare the dorsal spinous processes with the sternum on the ventrodorsal or dorsoventral projection. The spinous processes should sit at the midline of the sternum. On the lateral projection, the ribs on the dependent side should appear narrower and more cranial than those on the nondependent side, and the costophrenic angles should align closely. When the sternum and spine are offset, the degree of offset correlates with the magnitude of rotation, but the relationship is not linear. Even 5 to 10 degrees of rotation can produce apparent changes in cardiac silhouette width of clinical significance.

Abdominal radiographs use different landmarks. On the ventrodorsal projection, the kidneys should be equidistant from the vertebral column, and the wings of the ilia should appear symmetric. The transverse processes of the lumbar vertebrae should superimpose symmetrically over the vertebral bodies. On the lateral projection, the ribs of the two hemithoraces should overlap, and the femoral heads should align. Pelvic rotation is assessed by comparing the obturator foramina, which should be equal in size and shape.

Decision Points: When to Repeat and When to Proceed

The decision to repeat a rotated radiograph depends on three factors: the region imaged, the suspected disease process, and the patient's stability. A patient with respiratory distress may not tolerate repositioning for a perfect study, and a slightly rotated radiograph that answers the immediate question may be preferable to no image at all. Document the limitation and interpret accordingly.

Repeat the study when the rotation prevents assessment of the primary differential diagnosis. For example, a rotated thoracic radiograph that obscures the cranial mediastinum in a dog with suspected lymphoma warrants repetition. A rotated abdominal radiograph that places one kidney over the spine in a patient with suspected ureteral calculi also warrants repetition. Conversely, a rotated pelvic radiograph in a trauma patient with a confirmed femoral fracture may not require repetition if the fracture is fully characterized.

Patient status changes the threshold for repetition. Recumbent, sedated, or anesthetised patients tolerate repositioning better than dyspnoeic or unstable patients. For dyspnoeic patients, consider a dorsoventral projection instead of ventrodorsal, as this position causes less respiratory compromise. For patients with suspected spinal instability, minimize manipulation and accept minor rotation to avoid exacerbating injury.

Corrective Techniques by Region and Projection

Thorax

For the ventrodorsal projection, position the patient in sternal recumbency with the forelimbs extended cranially. Use foam wedges or sandbags to level the sternum with the spine. The head should be extended without twisting the neck, as cervical rotation transmits to the thorax. Verify symmetry by palpating the dorsal spinous processes and sternum before exposure. For the lateral projection, place the patient in true lateral recumbency with the dependent forelimb pulled cranially and the nondependent limb pulled caudally. This limb positioning prevents the nondependent limb from superimposing over the cranial thorax and reduces rotational torque on the body.

In deep-chested breeds, the thorax tends to roll toward the dependent side on lateral projections. Place a small radiolucent wedge under the sternum to maintain true lateral positioning. In barrel-chested breeds, the opposite problem occurs, and the sternum may sit higher than the spine. Adjust the wedge accordingly.

Abdomen and Pelvis

For abdominal radiographs, position the patient in dorsal recumbency for the ventrodorsal projection. Place sandbags on either side of the thorax and pelvis to prevent rolling. The sternum and spine should align in the sagittal plane. For the lateral projection, use the same limb positioning principles as the thorax, with the dependent hindlimb pulled caudally and the nondependent hindlimb positioned slightly cranial.

Pelvic radiographs require particular attention to symmetry because the paired bony structures are highly sensitive to rotation. Position the patient in dorsal recumbency with the hindlimbs extended caudally and symmetrically. Rotate the femurs medially to superimpose the patellae over the femoral trochleas. Verify that the obturator foramina appear symmetric before exposure.

Dental Radiography

Dental radiography presents unique positioning challenges because the intraoral sensor or film position is fixed by the oral anatomy. Rotation of the patient's head relative to the X-ray beam produces elongation or foreshortening of tooth roots and can obscure periapical pathology. The bisecting angle technique requires the beam to be perpendicular to the bisector of the angle between the sensor and the tooth long axis. Errors in head positioning change this angle and distort the image. For the parallel technique, the sensor must be parallel to the tooth long axis, which is achievable only in specific regions of the mouth. Familiarity with normal feline and canine oral anatomy is essential for recognizing when positioning has compromised the image, as described in the illustrated guide to feline oral anatomy and tooth extraction techniques Applied feline oral anatomy and tooth extraction techniques.

Troubleshooting Table: Positioning Errors, Artifacts, and Corrections

Equipment Choices That Reduce Positioning Errors

The choice of restraint equipment directly affects the frequency of positioning errors. Foam wedges of varying angles accommodate different body conformations. Sandbags provide stable but adjustable support. Velcro straps and positioning troughs reduce the need for manual restraint, which both improves positioning consistency and reduces radiation exposure to personnel. The American College of Veterinary Radiology resources provide guidance on imaging standards and radiation safety practices that inform equipment selection.

Digital radiography systems offer post-processing options that can partially compensate for exposure errors, but no software correction can fix rotation. The image is a two-dimensional projection of a three-dimensional object, and rotation changes the projection itself. Repeating the exposure with correct positioning is the only valid correction.

For practices using computed radiography, the imaging plate must be handled carefully to avoid artefacts from bending or scratching. For direct digital systems, the detector is fixed in the table or bucky, and patient positioning must accommodate the fixed detector location. In dental radiography, the choice between size 0, 1, 2, and 4 sensors depends on the patient's oral dimensions and the tooth being imaged. An oversized sensor forces angulation changes that introduce positioning errors.

Species and Patient Status Considerations

The correct positioning approach varies by species. In cats, the smaller body mass allows manual positioning with less equipment, but cats are more prone to sudden movement, and chemical restraint is often necessary for diagnostic-quality studies. In dogs, body conformation dictates positioning strategy. Deep-chested breeds require different wedge placement than barrel-chested breeds. Brachycephalic breeds present challenges for dental radiography because of dental crowding and root angulation.

In large animals, the principles of rotation recognition remain the same, but the practical approach differs. Standing sedated patients cannot be positioned in recumbency, and the X-ray beam must be aligned relative to the standing patient. Rotation is assessed using the same anatomic landmarks, but the reference points are the patient's sagittal plane relative to the beam, not the table surface. For equine distal limb radiographs, the beam must be centerd on the region of interest and aligned perpendicular to the bone's long axis. Rotation of the limb produces apparent changes in joint space width and can mimic or obscure pathology.

Production animals present additional constraints. In cattle and small ruminants, the available equipment may be portable and lower output, requiring longer exposure times that increase the risk of motion blur. Positioning must be efficient to minimize stress to the animal and risk to handlers. The WOAH terrestrial animal health standards address animal welfare during handling and restraint, which applies to radiographic positioning in production settings.

Patient status overrides positioning perfection in specific circumstances. Dyspnoeic patients should not be placed in dorsal recumbency. Patients with suspected spinal fractures should be positioned with minimal manipulation, accepting some rotation to avoid neurologic deterioration. Patients with abdominal distension may not tolerate lateral recumbency on either side. In each case, obtain the best image possible within the constraints, document the positioning limitation, and interpret accordingly.

Recognized Complications and Early Detection

Positioning errors rarely produce isolated artifacts. They compound. A rotated thorax that also suffers poor collimation obscures the pulmonary vasculature and degrades the study's diagnostic yield. The most consequential failure mode is the false-negative interpretation, where a lesion is present but hidden by superimposition or geometric distortion. Early detection depends on a disciplined review of every radiograph for the landmarks described in earlier sections before any interpretive statement is made.

Obliquity of the primary beam relative to the anatomy of interest produces elongation or foreshortening. This matters most in the pelvis, where the obturator foramina and iliac wings serve as built-in level indicators. When the patient is rotated about the long axis, the pelvis appears asymmetric and the sacroiliac joints lose their parallel orientation. When the patient is rotated in the dorsal plane, the obturator foramina become unequal in size and the iliac wings project at different heights. Each of these findings should trigger an immediate repeat, because measurements taken from a rotated pelvis, such as those used for hip dysplasia screening, are unreliable.

Underexposure and overexposure are not positioning errors, but they interact with them. A rotated patient increases the effective tissue thickness the beam must penetrate, which can produce an underexposed image if the technique chart was set for a true lateral or ventrodorsal projection. The reverse occurs when a thick body part is rotated out of the beam path. Technique charts assume correct positioning, and the operator must adjust exposure factors when positioning is compromised, or better, repeat the study with correct positioning.

Common Errors by Less Experienced Operators

Students and new graduates most often err in three ways. First, they accept a radiograph that is nearly correct, reasoning that the abnormality, if present, will still be visible. This is a dangerous assumption. Rotation of even 5 to 10 degrees can obscure a small pulmonary nodule or a subtle effusion line. The threshold for repeating should be low, and the cost of a repeat study is far lower than the cost of a missed diagnosis.

Second, they position the patient and then fail to verify the position before exposing. A sedated or anesthetised patient can shift during the few seconds between positioning and exposure, particularly if the operator steps away to the control panel. Verification of landmarks immediately before exposure, using palpable bony prominences and visual alignment, is the single most effective corrective action.

Third, they collimate too tightly in an attempt to compensate for poor positioning. Tight collimation around a rotated structure excludes the very landmarks needed to recognize the rotation. The collimated field should always include the full region of interest plus the reference landmarks, even if this means a slightly larger field than ideal. The professional practice resources from the AVMA emphasize that image quality and patient safety are both served by correct positioning and collimation, not by one at the expense of the other.

Limitations of the Evidence and Areas of Expert Difference

The published evidence on veterinary positioning errors is largely descriptive and experiential. Controlled studies comparing diagnostic accuracy across degrees of rotation are scarce, and most guidance derives from expert consensus and extrapolation from human radiology. The empirical review of teleradiology evidence notes that diagnostic accuracy depends on image quality, but it does not quantify the threshold at which rotation degrades accuracy for specific lesions.

Expert opinion differs on how strictly to apply repeat criteria. Some radiologists advocate repeating any study with visible rotation, while others accept mild rotation when the clinical question is narrow, such as confirming the presence of a large mass or a radiopaque foreign body. This difference reflects the absence of dose-response data linking rotation magnitude to diagnostic error. In dental radiography, the illustrated guide to feline oral anatomy and tooth extraction stresses that precise beam alignment is essential for evaluating root and periodontal structures, where even small errors can mimic pathology. The same principle applies to the appendicular skeleton, where subtle periosteal reactions can be obscured by obliquity.

Referral, Consultation, and Reporting

Referral to a veterinary radiologist is warranted when the study remains equivocal after repeat positioning, when the clinical suspicion is high but the radiographs are normal, or when the case involves complex anatomy such as the skull, spine, or joints. Teleradiology consultation is widely available and has demonstrated concordance with conventional interpretation, as documented in the review of teleradiology applications. Submission of images with a clear description of the positioning difficulties encountered allows the radiologist to weight their interpretation accordingly.

Laboratory involvement is indicated when radiographic findings suggest a systemic process that requires hematologic or biochemical confirmation, such as a suspected neoplasia or metabolic bone disease. Radiography identifies the lesion, but it does not establish aetiology.

Regulatory reporting obligations vary by jurisdiction and species. In production animal practice, radiographic findings that support a notifiable disease suspicion must be reported to the relevant animal health authority. The terrestrial animal health standards published by WOAH define the reporting framework for listed diseases, and practitioners should consult their regional authority for specific requirements. In companion animal practice, reporting obligations are limited, but documentation of positioning errors and repeat studies in the medical record is a professional standard that protects both the patient and the practice.

Troubleshooting Table

Frequently Asked Questions

How do I decide whether to repeat a rotated radiograph when the patient is unstable or heavily sedated?

Prioritize patient safety over image perfection. If the patient is dyspneic, hypotensive, or recovering from anesthesia, a diagnostic-quality study may be impossible without additional risk. In these cases, obtain the orthogonal projection and any additional views that can be performed with minimal handling, then interpret the rotated study with explicit acknowledgment of its limitations in the report. The American College of Veterinary Radiology resources emphasize that image quality must be balanced against patient welfare. If the rotated view still answers the clinical question, such as confirming a large volume pleural effusion, proceed. If subtle interstitial disease or a small pulmonary nodule is the question, repeat once the patient stabilizes.

What positioning adjustments compensate for a patient that cannot maintain sternal recumbency?

Use sandbags, foam wedges, and tape to support the patient instead of relying on manual restraint alone. For a patient that rolls into lateral, position the primary beam and cassette first, then place the patient and secure the thorax at the sternum and pelvis simultaneously. A V-trough or vacuum cushion maintains sternal position in many brachycephalic and barrel-chested patients. For patients with respiratory distress, consider a standing or sitting projection for the thorax, which preserves sternal recumbency indirectly by allowing the patient to choose a comfortable posture. The MSD Veterinary Manual notes that species and conformation alter normal radiographic appearance, so a mildly rotated study in a deep-chested dog may be more acceptable than the same error in a barrel-chested dog.

How does rotation affect radiographic interpretation differently in avian and exotic patients?

Avian patients have a fused synsacrum and relatively fixed coelomic organs, so rotation produces predictable but severe distortion. A 10 degree rotation in a bird can shift the cardiac silhouette markedly relative to the sternum and obscure the normally distinct air sac spaces. Respiratory motion is also faster, so short exposure times matter more than perfect positioning. In reptiles, rotation of the shell or coelom makes laterolateral views particularly difficult to interpret because the two lung fields overlap asymmetrically. For both groups, obtain a dorsoventral instead of ventrodorsal view when possible, as it is better tolerated and less likely to induce rotation from struggling. The WOAH terrestrial animal health standards address species-specific handling and welfare considerations that apply when positioning nondomestic patients.

What should I document in the medical record when a radiograph is repeated for positioning error?

Record the initial projection, the specific positioning error identified, the corrective action taken, and the final image quality assessment. Include the number of exposures and the total radiation dose estimate if your system tracks dose-area product. Note any patient factors that contributed to the error, such as obesity, fractious behavior, or respiratory distress, because these justify the repeat study and inform future imaging plans. The AVMA practice resources provide guidance on medical record standards that support defensible documentation. If the rotated image was interpreted despite the error, state that explicitly and describe how the rotation may have affected the findings. This protects the medical record and helps the next clinician understand why a particular study is or is not reliable.

How do I manage positioning errors when using a portable or handheld radiography unit?

Portable units produce lower output and require longer exposure times, which increases motion artifact risk and makes repeat studies more likely. Compensate by using higher speed imaging plates or digital detectors, collimating tightly to the region of interest, and using the shortest exposure time the unit allows. Secure the patient more aggressively because the longer exposure window amplifies the effect of any movement. For dental radiography, the dental radiography technology review describes how digital detectors reduce retakes compared with film, but positioning errors remain the dominant cause of nondiagnostic images. If the portable unit cannot achieve adequate exposure for a thick body part, refer to a fixed unit instead of accepting a rotated, underexposed study.

How should I explain a repeated radiograph to a client without undermining their confidence in the practice?

Use straightforward language that attributes the repeat to technical factors instead of patient factors. State that the first image was slightly angled, which can hide or mimic disease, and that a second image is needed to be certain of the diagnosis. Avoid blaming the patient or the equipment. Emphasize that the additional image improves diagnostic confidence and may prevent an unnecessary procedure or an incorrect treatment. The teleradiology evidence review notes that diagnostic accuracy depends on image quality, and this rationale translates directly to client communication. Most clients accept a repeat study when it is framed as a quality measure. If the client declines, document the refusal and interpret the available images with appropriate caveats.

Related Clinical & Scientific Guides

• MRI Monitoring of Brain Tumor Response to Therapy in Dogs
• Ultrasound-Guided Drainage of Abscesses in Small Animals
• Radiographic Monitoring of Total Hip Replacement in Dogs

References and Further Reading

• Dental Radiographic/Digital Radiography Technology along with Biological Agents in Human Identification.. 2022.
• The Empirical Foundations of Teleradiology and Related Applications: A Review of the Evidence.. 2016.
• Applied feline oral anatomy and tooth extraction techniques: an illustrated guide.. 2014.
• American College of Veterinary Radiology Resources. American College of Veterinary Radiology.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.
• WOAH Terrestrial Animal Health Code. WOAH.

Related Articles

• Musculoskeletal Radiography in Small Animals: Positioning and Interpretation
• Dental Radiography Positioning and Interpretation in Dogs and Cats
• Contrast Radiography in Veterinary Practice: Indications and Protocols
• Abdominal Radiographic Positioning and Normal Anatomy in Small Animals
• Radiation Safety in Veterinary Radiography: Principles and Practice

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.