Implementation of Dose Monitoring Software in the Clinical Routine: First Experiences

Abstract

Purpose: Radiation exposure of the public as a result of medical imaging has significantly increased during the last decades. To have a tool to register and control patient dose exposure, we implemented dose monitoring software at our institution and first connected our computed tomography (CT) scanners.

Materials and Methods: CT dose data from July 2014 to February 2015 was retrospectively analyzed using dose monitoring software. We evaluated a number of scans above predefined dose thresholds (“alerts”), assessed reasons for alerts and compared data of two CT scanners, one located close to the emergency room (“emergency CT scanner”) and one mainly used on an outpatient basis (“clinical routine CT scanner”). To check for statistically significant differences between scanners, chi-square-tests were performed.

Results: A total of 8883 scans were acquired (clinical routine CT scanner, n = 3415; emergency CT scanner, n = 5468) during which 316 alerts were encountered (alert quota, 4 %). The overall alert quota ranged from 2 – 5 % with significantly higher values for the clinical routine CT scanner. Reasons for alerts were high BMI (51 %), patient off-centering (24 %), scan repetition (11 %), orthopedic hardware (9 %), or other (5 %). Scan repetition was necessary significantly more often with the emergency CT scanner (p = 0.019), while high BMI, off-centering and orthopedic hardware were more frequently seen with the clinical routine CT scanner (for all, p < 0.05). There was a good correlation between high body weight and dose above threshold (r = 0.585).

Conclusion: Implementation of dose monitoring software in the clinical routine was successfully accomplished and provides important information regarding patient radiation protection.

Key Points:

1. Implementation of dose monitoring software in the clinical routine can be successfully accomplished.

2. Dose notifications are due to human error or patient-specific factors.

3. Dose monitoring software provides important information regarding radiation protection of patients.

Citation Format:

• Heilmaier C, Zuber N, Bruijns B et al. Implementation of Dose Monitoring Software in the Clinical Routine: First Experiences. Fortschr Röntgenstr 2016; 188: 82 – 88

Zusammenfassung

Ziel: Die Strahlenbelastung der Bevölkerung durch medizinische Bildgebung hat in den letzten Jahrzehnten deutlich zugenommen. Um die Strahlenbelastung der Patienten systematisch aufzeichnen und kontrollieren zu können, wurde in unserem Institut eine Dosis-Monitoring-Software installiert und zunächst mit den Computertomografen (CTs) verbunden.

Material und Methoden: Mithilfe der Dosis-Monitoring-Software wurden die Dosisdaten von zwei CTs zwischen Juli 2014 und Februar 2015 retrospektiv ausgewertet. Das eine CT befindet sich neben der Notaufnahme („Notfall-CT“), das andere CT wird überwiegend für stationäre und ambulante Patienten verwendet („Routine-CT“). Die Daten wurden im Hinblick auf die Anzahl der Untersuchungen mit Dosiswerten oberhalb festgelegter Schwellenwerte („Alerts“) ausgewertet und die Ursachen für diese für beide CTs analysiert. Um signifikante Unterschiede zwischen beiden Geräten festzustellen, wurden Chi-Quadrat-Tests durchgeführt.

Ergebnisse: Insgesamt wurden 8883 Untersuchungen akquiriert (Routine-CT: 3415, Notfall-CT: 5468). Hierbei wurden 316 Alerts registriert (Quote: 4 %). Die Quote der Alerts schwankte zwischen 2 und 5 % zwischen den Monaten und Geräten, wobei am Routine-CT signifikant mehr Alerts nachgewiesen wurden. Ursachen für die Alerts waren hoher BMI (51 %), ungenaue Lagerung der Patienten im Isozenter (24 %), Untersuchungswiederholungen (11 %), Artefakte durch einliegendes Osteosynthesematerial (9 %) oder andere Gründe (5 %). Scanwiederholungen waren signifikant häufiger am Notfall-CT notwendig (p = 0,019), während hoher BMI, ungenaue Patientenlagerung oder einliegendes Osteosynthesematerial öfter Alerts am Routine-CT verursachten (für alle p < 0,05). Es zeigte sich eine gute Korrelation zwischen dem BMI und den Dosiswerten über dem Schwellenwert (r = 0,585).

Schlussfolgerung: Eine Dosis-Monitoring-Software kann erfolgreich in den klinischen Alltag eingeführt werden und liefert wichtige Informationen betreffend den Strahlenschutz der Patienten.

Kernaussagen:

1. Eine Dosis-Monitoring-Software kann erfolgreich in den klinischen Alltag eingeführt werden.

2. Dosiswarnungen sind entweder durch menschliche Fehler oder patientenspezifische Faktoren bedingt.

3. Durch eine Dosis-Monitoring-Software werden wichtige Informationen betreffend den Strahlenschutz der Patienten gewonnen.

Key words

CT - radiation safety - QA/QC

• References

• 1 Amis ES, Butler PF, Applegate KE et al. American College of Radiology white paper on radiation dose in medicine. J Am Coll Radiol JACR 2007; 4: 272-284
• 2 Schauer DA, Linton OW. National Council on Radiation Protection and Measurements report shows substantial medical exposure increase. Radiology 2009; 253: 293-296
• 3 Boone JM, Hendee WR, McNitt-Gray MF et al. Radiation exposure from CT scans: how to close our knowledge gaps, monitor and safeguard exposure--proceedings and recommendations of the Radiation Dose Summit, sponsored by NIBIB, February 24–25, 2011. Radiology 2012; 265: 544-554
• 4 Robinson TJ, Robinson JD, Kanal KM. Implementation of the ACR dose index registry at a large academic institution: early experience. J Digit Imaging 2013; 26: 309-315
• 5 Brink JA, Amis ES. Image Wisely: a campaign to increase awareness about adult radiation protection. Radiology 2010; 257: 601-602
• 6 Goske MJ. Image gently: child-sizing radiation dose for children. JAMA Pediatr 2013; 167: 1083
• 7 Strauss KJ, Goske MJ, Kaste SC et al. Image gently: Ten steps you can take to optimize image quality and lower CT dose for pediatric patients. Am J Roentgenol Am J Roentgenol 2010; 194: 868-873
• 8 European Society of Radiology (ESR). Renewal of radiological equipment. Insights Imaging 2014; 5: 543-546
• 9 McCollough CH, Leng S, Yu L et al. CT dose index and patient dose: they are not the same thing. Radiology 2011; 259: 311-316
• 10 Neumann RD, Bluemke DA. Tracking radiation exposure from diagnostic imaging devices at the NIH. J Am Coll Radiol. JACR 2010; 7: 87-89
• 11 Treier R, Aroua A, Verdun FR et al. Patient doses in CT examinations in Switzerland: implementation of national diagnostic reference levels. Radiat Prot Dosimetry 2010; 142: 244-254
• 12 Brenner DJ, Hall EJ. Cancer risks from CT scans: now we have data, what next?. Radiology 2012; 265: 330-331
• 13 Hendee WR, O’Connor MK. Radiation risks of medical imaging: separating fact from fantasy. Radiology 2012; 264: 312-321
• 14 Sadigh G, Khan R, Kassin MT et al. Radiation safety knowledge and perceptions among residents: a potential improvement opportunity for graduate medical education in the United States. Acad Radiol 2014; 21: 869-878
• 15 Verdun FR, Gutierrez D, Vader JP et al. CT radiation dose in children: a survey to establish age-based diagnostic reference levels in Switzerland. Eur Radiol 2008; 18: 1980-1986
• 16 Einstein AJ. Effects of radiation exposure from cardiac imaging: how good are the data?. J Am Coll Cardiol 2012; 59: 553-565
• 17 Armao D, Smith JK. The health risks of ionizing radiation from computed tomography. N C Med J 2014; 75: 126-128–131
• 18 Hall EJ, Brenner DJ. Cancer risks from diagnostic radiology: the impact of new epidemiological data. Br J Radiol 2012; 85: e1316-e1317
• 19 Brenner DJ, Shuryak I, Einstein AJ. Impact of reduced patient life expectancy on potential cancer risks from radiologic imaging. Radiology 2011; 261: 193-198
• 20 Brenner DJ, Hall EJ. Computed tomography-an increasing source of radiation exposure. N Engl J Med 2007; 357: 2277-2284
• 21 AlSuwaidi JS, AlBalooshi LG, AlAwadhi HM et al. Continuous monitoring of CT dose indexes at Dubai Hospital. Am J Roentgenol Am J Roentgenol 2013; 201: 858-864
• 22 Rehani M, Frush D. Tracking radiation exposure of patients. Lancet 2010; 376: 754-755
• 23 Chintapalli KN, Montgomery RS, Hatab M et al. Radiation dose management: part 1, minimizing radiation dose in CT-guided procedures. Am J Roentgenol Am J Roentgenol 2012; 198: W347-W351
• 24 Kaasalainen T, Palmu K, Lampinen A et al. Effect of vertical positioning on organ dose, image noise and contrast in pediatric chest CT--phantom study. Pediatr Radiol 2013; 43: 673-684
• 25 Kaasalainen T, Palmu K, Reijonen V et al. Effect of patient centering on patient dose and image noise in chest CT. Am J Roentgenol Am J Roentgenol 2014; 203: 123-130
• 26 Habibzadeh MA, Ay MR, Asl ARK et al. Impact of miscentering on patient dose and image noise in x-ray CT imaging: phantom and clinical studies. Phys Medica PM Int J Devoted Appl Phys Med Biol Off J Ital Assoc Biomed Phys AIFB 2012; 28: 191-199
• 27 Raman SP, Mahesh M, Blasko RV et al. CT Scan Parameters and Radiation Dose: Practical Advice for Radiologists. J Am Coll Radiol 2013; 10: 840-846
• 28 Wang G, Gao J, Zhao S et al. Achieving consistent image quality and overall radiation dose reduction for coronary CT angiography with body mass index-dependent tube voltage and tube current selection. Clin Radiol 2014; 69: 945-951
• 29 Winklhofer S, Benninger E, Spross C et al. CT metal artefact reduction for internal fixation of the proximal humerus: value of mono-energetic extrapolation from dual-energy and iterative reconstructions. Clin Radiol 2014; 69: e199-e206
• 30 Turner AC, Zhang D, Khatonabadi M et al. The feasibility of patient size-corrected, scanner-independent organ dose estimates for abdominal CT exams. Med Phys 2011; 38: 820-829