Minimizing patient Exposure part 8: Positioning

In radiographic imaging, the balance between diagnostic clarity and patient safety is achieved not just through technology, but through technique—especially positioning. How a patient is aligned relative to the x-ray beam, image receptor, and anatomical area of interest profoundly influences the amount of radiation required, the need for repeat exams, and the accuracy of diagnosis.

Positioning is often overlooked as a radiation safety tool, but in reality, it is one of the most effective ways to minimize exposure. When done correctly, proper positioning ensures that the first image is the only image, reducing repeat exposures, improving image quality, and allowing for lower technique settings due to optimal geometry.

This post will explore:

• The relationship between positioning and radiation dose

• Strategies for accurate and efficient positioning

• Special considerations for pediatric and bariatric patients

• How communication and preparation reduce unnecessary exposure

The Link Between Positioning and Radiation Dose

At its core, radiographic positioning is about maximizing anatomical visibility while minimizing exposure. Mispositioning not only jeopardizes image quality but can also result in repeat imaging, doubling or even tripling the patient’s dose. Additionally, poor alignment can force the technologist to increase mAs or kVp to compensate for suboptimal beam paths or distorted anatomy.

Examples of dose increase due to poor positioning include:

• Rotated or oblique positioning that causes structures to overlap, obscuring pathology

• Misalignment with the grid, which can cause grid cutoff, resulting in underexposed areas that require repeat images

• Incorrect SID or OID, which can reduce sharpness and contrast, again necessitating retakes

Correct positioning, on the other hand, provides consistent beam entrance paths, minimizes tissue superimposition, and ensures the shortest and most direct beam route through the area of interest. This reduces scatter, improves spatial resolution, and supports the use of lower exposure factors.

Strategies for Accurate Positioning

1. Know Your Landmarks

Accurate positioning begins with a strong foundation in anatomical landmarks. Each projection—whether chest, lumbar spine, or extremity—has clearly defined bony or soft tissue reference points that guide proper alignment. Consistently locating these landmarks ensures that the beam is centered appropriately and the anatomy is visualized in its true form.

2. Use Positioning Aids

Sponges, immobilizers, wedges, and straps are not just conveniences—they are safety tools. They:

• Help maintain the correct anatomical plane

• Reduce voluntary and involuntary motion

• Enable repeatable and reliable positioning across images

Even simple tools like a positioning sponge under the lumbar spine during an AP abdomen can flatten the curvature and reduce part thickness—allowing for a lower technique and less scatter.

3. Master Angulation

Understanding when and how to use tube angulation is essential. An improperly angled beam can distort anatomy, increase the volume of tissue the beam travels through, and result in blurred or non-diagnostic images. By mastering angulation, technologists can:

• Align the beam with intervertebral spaces, joint gaps, or other specific anatomy

• Reduce magnification by minimizing OID

• Avoid unnecessary tissue exposure beyond the area of interest

Patient-Specific Positioning: One Size Does Not Fit All

Every patient is unique, and so are their imaging needs. Radiographers must adapt their approach to each individual’s body type, age, and condition. This will be the focus of the next section, where we’ll examine how to adjust positioning to reduce dose in pediatric, bariatric, and trauma patients, and why communication is just as important as physical technique.

Adapting Positioning for Special Populations

While general positioning techniques provide a strong foundation, technologists must also be prepared to adapt based on individual patient factors. Pediatric, bariatric, and trauma patients present unique challenges that require flexibility, creativity, and enhanced attention to radiation safety.

Pediatric Patients: Precision Over Power

Children are especially vulnerable to ionizing radiation because of their rapidly dividing cells and longer life expectancy, which increases their risk of radiation-induced effects. In pediatric imaging, accurate positioning is essential to avoiding repeat exposures, which can dramatically impact cumulative dose.

Positioning Tips for Pediatric Patients:

• Immobilization devices such as Pigg-O-Stat or papoose boards help reduce motion and ensure proper alignment.

• Distraction techniques and communication geared to the child’s developmental level can prevent fear and fidgeting.

• Use smaller focal spots and tighter collimation to match the anatomy more precisely.

• Receptors should be selected based on the child’s size to avoid cropping or underexposing.

• Consider alternative views or modified positions that expose less of the body without compromising diagnostic value.

The technologist’s goal is to achieve perfect positioning on the first attempt—because every repeat in a pediatric exam can double the risk.

Bariatric Patients: Navigating Complexity Without Overexposure

Obese patients often require more radiation to penetrate dense tissues, but proper positioning can reduce that increase. Positioning challenges include increased body part thickness, mobility limitations, and difficulties in locating landmarks.

Positioning Strategies for Bariatric Patients:

• Use palpation with patience to identify key landmarks; visual cues may not be reliable.

• Increase SID where possible to reduce magnification.

• Use grid alignment tools or virtual grid technologies in digital systems to manage scatter without excessive dose.

• Employ table pads or positioning sponges that support the patient’s body and improve alignment.

• Always collimate tightly, even if anatomy appears larger—scatter increases exponentially with field size.

Optimizing positioning for bariatric patients helps avoid unnecessary retakes, which can become especially problematic due to higher default techniques.

Trauma Patients: Working with Limitations

Trauma patients are often unable to cooperate or assume traditional positions due to injury, immobilization devices, or pain. In these cases, the challenge becomes obtaining a diagnostic image without compromising safety or repeating exposures.

Best Practices in Trauma Positioning:

• Use cross-table lateral and modified projections when standard positions are not feasible.

• Elevate or rotate equipment instead of moving the patient.

• Utilize air-gap technique or mobile grid options if scatter becomes excessive.

• Keep receptor alignment and centering precise to avoid cone cut or image distortion.

• Prioritize communication with the care team to reposition devices or supports only when safe.

Trauma imaging demands a high level of technical skill and adaptability. Every effort to get the shot right the first time reduces dose and enhances care.

The Role of Communication in Positioning

Positioning isn’t just physical—it’s also psychological. Clear, confident communication with patients can reduce motion, anxiety, and resistance. Patients who understand what to expect are far more likely to comply with instructions, resulting in better alignment and fewer repeat exposures.

Communicative Techniques that Enhance Positioning:

• Explain the purpose of the exam in simple terms.

• Describe exactly how the patient should position themselves and demonstrate if possible.

• Provide reassurance and verbal guidance throughout the procedure.

• Anticipate discomfort and adjust with supportive aids or pillows.

Effective communication makes patients partners in the imaging process, which supports safer, faster, and more accurate procedures.

Reproducibility and Immobilization: Key to Consistent Low-Dose Imaging

Reproducibility in radiography is the ability to produce the same image quality across different patients, different technologists, and different days. This consistency is only possible with precise, standardized positioning techniques. When technologists rely on reproducible landmarks, established routines, and immobilization tools, exposure settings can be tailored more accurately—often at lower doses—without sacrificing diagnostic value.

Immobilization: The Unsung Hero of Dose Reduction

Motion blur is a common reason for repeat imaging. This is especially problematic in exams involving:

• Pediatrics

• Elderly patients

• Painful injuries or musculoskeletal trauma

• Nervous or claustrophobic individuals

Proper immobilization ensures:

• Patient remains in the correct anatomical position

• The beam-target-receptor alignment is not disrupted

• The need for repeated exposures due to motion is significantly reduced

Immobilization can include:

• Foam sponges and wedges

• Sandbags

• Head clamps or straps

• Velcro restraints or papoose boards (particularly in pediatrics)

• Support from caregivers or trained staff when needed

By preventing motion and preserving the integrity of the original positioning, immobilization becomes a critical factor in minimizing radiation exposure.

Positioning and Image Quality: The Dose Efficiency Link

One of the most overlooked relationships in radiography is how proper positioning improves image quality, which then allows for lower radiation output. When the anatomy of interest is optimally aligned and centered:

• Less scatter is produced

• Collimation can be tighter

• Contrast is enhanced

• The need for post-processing or digital compensation is reduced

Poor positioning may require:

• Additional exposures due to missed anatomy

• Higher exposure factors to compensate for anatomical distortion or poor visualization

• Complex post-processing that can introduce artifacts or mask important structures

The clearest, most useful images come from intentional, precise positioning—not from brute force exposure increases.

Positioning and the ALARA Principle

Every radiation safety protocol in medical imaging is guided by ALARA: As Low As Reasonably Achievable. Positioning is one of the most direct and effective methods for upholding this standard because it doesn’t rely on costly equipment, advanced software, or post-exam interventions. It’s a front-line strategy that begins before the first x-ray is even taken.

Positioning aligns perfectly with all three ALARA strategies:

• Time: Proper positioning reduces the need for repeat exams, shortening total exposure time.

• Distance: Good positioning allows for optimal SID and minimizes beam divergence.

• Shielding: With precise targeting and collimation, unnecessary tissues are naturally excluded from the beam.

Technologists who prioritize positioning not only improve efficiency and image quality—they also demonstrate the highest standard of care.

Conclusion: Positioning Is Patient Protection

In the pursuit of safe, effective diagnostic imaging, positioning is not a routine—it’s a safeguard. It determines whether a single image will suffice or whether a patient will be exposed multiple times. It influences the radiation dose needed to achieve diagnostic clarity. And it’s entirely within the control of the technologist.

When technologists approach positioning with intention, knowledge, and adaptability, they embody the principles of radiation safety in their purest form. They become not just image makers, but protectors of patient well-being.

By mastering positioning and integrating it with other dose-reduction strategies like proper collimation, shielding, and receptor use, radiologic technologists turn every exam into a precise, patient-centered act of care.

Every patient deserves the best image at the lowest dose—and that begins with positioning done right.