Assessment of patient radiation dose in conventional lumbar spine radiography: A multicenter study in the Souss Massa region, Morocco

This multicenter study in the Souss Massa region of Morocco evaluated patient radiation doses for conventional lumbar spine radiography across four hospitals, finding that while significant variations existed between facilities, all measured entrance surface doses and dose area products remained below established diagnostic reference levels.

The Gist

Imagine your body is a delicate house, and medical X-rays are like powerful flashlights used by doctors to see inside the walls without breaking them down. The problem is, if you shine that flashlight too brightly or for too long, you might accidentally "burn" the house (radiation exposure), even if you're just trying to find a leak (a broken bone).

This paper is like a safety inspector's report from a specific neighborhood in Morocco (the Souss Massa region). The inspectors wanted to make sure the doctors and technicians were using the flashlights wisely.

Here is the breakdown of their findings in simple terms:

1. The Mission: Checking the Flashlights

The researchers looked at 142 people who had their lower backs (lumbar spine) X-rayed at four different hospitals. They wanted to answer one big question: "Are we using just enough light to see the problem, or are we blasting the patients with too much radiation?"

They measured two things:

• The "Burn" on the Skin (Entrance Surface Dose): How much radiation hits the patient's skin right when the X-ray starts.
• The Total "Light Flood" (Dose Area Product): The total amount of radiation energy spread over the whole area being scanned.

2. The Rules of the Game (The Safety Limits)

Think of Diagnostic Reference Levels (DRLs) as the "Speed Limits" on a highway.

• If you drive at 60 mph in a 60 mph zone, you are safe.
• If you drive at 120 mph, you are in danger.
• The goal isn't to drive at 0 mph (because then you can't see anything), but to stay comfortably under the speed limit.

In this study, the "Speed Limit" was set by international experts (like the IRSN). The researchers wanted to see if the hospitals in Morocco were driving safely.

3. The Results: Everyone Passed!

The big news is that all four hospitals were driving well under the speed limit.

• The "Speed" was low: The radiation doses they measured were actually much lower than the maximum allowed limits.
  • For the front-to-back view, they were using only about 53% of the allowed limit.
  • For the side view, they were using only about 30% of the allowed limit.
• The "Total Flood" was also low: The total energy used was less than half of what is considered the maximum safe limit.

Analogy: Imagine the safety limit is a bucket that can hold 10 gallons of water. The hospitals in this study only poured in about 3 to 5 gallons. They are being very careful!

4. Why Were Some Hospitals Different?

Even though everyone passed, some hospitals used slightly more "water" (radiation) than others.

• Inzegane Hospital used the most radiation (though still safely under the limit).
• Taroudant Hospital used the least.

Why the difference?
Think of it like taking photos with different cameras:

• Old vs. New Cameras: Some hospitals had older X-ray machines that needed more "flash" to get a clear picture. Newer digital machines are more sensitive and need less flash.
• The Photographer's Skill: Some technicians might have been more careful with the settings (like the voltage or how long the beam was on) than others.
• The Size of the Frame: If you take a photo of a whole room instead of just a face, you need more light. If the technicians made the X-ray beam too big, the dose went up.

5. The "Human" Side of the Story

The researchers also talked to the 20 technicians (the people actually pressing the buttons). They found a few interesting things:

• Young Team: The staff was relatively young.
• Missing the Manual: Shockingly, 85% of the technicians didn't even know what the "Speed Limits" (DRLs) were! They didn't have a rulebook or a guide to tell them how to optimize the dose.
• No Physics Experts: None of the hospitals had a dedicated "Radiation Safety Coach" (a medical physicist) on staff to double-check their work.

6. The Final Verdict

The Good News: The patients in this region are safe. The hospitals are doing a great job keeping radiation low, even better than some European studies.

The Advice for the Future:
Even though they are safe now, the authors say, "Don't get complacent!"

• Keep a Logbook: They need to keep checking the doses regularly, like a car owner checking tire pressure.
• Train the Staff: The technicians need to learn about these safety limits so they can do their jobs even better.
• Get a Coach: They strongly suggest hiring a specialist (a medical physicist) to act as a safety coach to ensure the "flashlights" stay optimized forever.

In a nutshell: The doctors in this Moroccan region are using X-rays very responsibly. They aren't over-exposing patients. However, to keep it that way, they need to teach their staff the rules and get a little extra help from experts.

Technical Summary

1. Problem Statement

Diagnostic radiology is a primary source of artificial radiation exposure to the population. While Diagnostic Reference Levels (DRLs) serve as critical tools for optimizing radiation doses and ensuring patient safety, there is a significant lack of data regarding routine radiographic procedures in developing regions. Specifically, in Morocco, studies evaluating radiation doses during conventional lumbar spine radiography are scarce. Without local data, it is difficult to determine if current practices in the Souss Massa region comply with international safety standards or if optimization is required.

2. Methodology

• Study Design: A descriptive, cross-sectional, multicenter investigation.
• Setting & Duration: Conducted between April and June 2017 across four hospitals in the Souss Massa region of Morocco (Agadir, Inzegane, Tiznit, and Taroudant).
• Population:
  • Patients: 142 individuals undergoing conventional lumbar spine radiography.
  • Personnel: 20 radiology technicians (71% participation rate of eligible staff).
• Data Collection:
  • Demographic data (age, gender).
  • Technical exposure parameters: Tube voltage (kV), tube current-time product (mAs), focus-to-film distance (FFD), field size, and filtration.
  • All examinations were performed with a standard FFD of 100 cm; no fluoroscopy was used.
• Dose Calculation:
  • Entrance Surface Dose (ESD/De): Estimated using MICADO software based on recorded radiographic parameters.
  • Dose Area Product (DAP): Calculated subsequently.
• Statistical Analysis: The 75th percentile of the measured doses was calculated for the region and individual hospitals. These values were compared against established Diagnostic Reference Levels (DRLs) to assess compliance.

3. Key Contributions

• First Regional Baseline: This study provides the first comprehensive dataset on patient radiation doses for lumbar spine radiography in the Souss Massa region of Morocco.
• DRL Validation: It establishes local 75th percentile values to serve as a baseline for future quality assurance programs.
• Staff Awareness Gap: The study highlights a critical knowledge gap, noting that 85% of participating technicians had no knowledge of DRLs and that no formal dose optimization protocols existed in the departments.
• Comparative Analysis: It offers a direct comparison between local Moroccan practices and international data (specifically a 2012 Swiss study), demonstrating that lower-resource settings can achieve dose levels comparable to or better than developed nations.

4. Key Results

Demographics:

• The patient cohort was 52% male and 48% female.
• The majority (39%) were aged 40–59 years.

Dose Metrics (Regional 75th Percentile):

• Entrance Surface Dose (De):
  • Anteroposterior (AP) projection: 5.33 mGy (46.7% below the 10 mGy DRL).
  • Lateral projection: 7.38 mGy (70.48% below the 25 mGy DRL).
• Dose Area Product (DAP):
  • AP projection: 1840.9 mGy·cm² (59.9% below the 4500 mGy·cm² DRL).
  • Lateral projection: 2783.65 mGy·cm² (65.2% below the 8000 mGy·cm² DRL).

Hospital Variations:

• Inzegane recorded the highest doses (De: 6.02 mGy AP / 8.37 mGy Lat; DAP: 2164.23 / 3994.97 mGy·cm²).
• Taroudant recorded the lowest doses (De: 3.7 mGy AP / 6.37 mGy Lat; DAP: 1301.13 / 2271.45 mGy·cm²).
• Compliance: All hospitals remained well within the established DRLs.

International Comparison:

• The Souss Massa region's doses were significantly lower than those reported in a 2012 Swiss study (e.g., Swiss lateral De was 10.22 mGy vs. 7.38 mGy in this study).

Operational Observations:

• Most technicians performed 0–4 examinations per day.
• No fluoroscopy was utilized during these examinations.
• Variations in dose between hospitals were attributed to differences in X-ray tube characteristics (filtration), detector sensitivity, and specific radiographic protocols (kV, mAs, field size).

5. Significance and Conclusion

• Safety Status: The study concludes that radiation doses for lumbar spine radiography in the Souss Massa region are within acceptable limits and demonstrate good optimization, with reductions of >50% compared to DRLs.
• Need for Training: Despite the favorable dose levels, the lack of DRL knowledge among 85% of staff and the absence of formal protocols indicate a need for improved education.
• Recommendations:
  • Implement continuous monitoring of patient exposure.
  • Conduct periodic staff training on dose calculation and DRLs.
  • Involve medical physicists or dosimetrists to oversee radiation safety and protocol optimization.
  • Establish formal institutional guidelines for dose optimization.

This study confirms that effective radiation protection is achievable in the region but emphasizes that maintaining these standards requires ongoing education and structural support from medical physics experts.