Radiation dose measurement for patients undergoing common spine medical x-ray examinations and proposed local diagnostic reference levels

A review of 20 years publication in the field of radiation protection in diagnostic radiology in Iran

In recent years, knowing the risks of stochastic effects of radiation, patient dose in diagnostic radiology is taken in to consideration extensively. Many countries and international organization, including International Commission on Radiological Protection, use quantities such as dose area product, entrance surface dose, etc. in radiological investigations, which serve as a guide for patient dose reduction. The concept of diagnostic reference level (DRL) is used to optimizing the dose of patients undergoing diagnostic radiology examinations. The present study aimed to review the studies on the DRLs in Iran. This study was conducted to review the status of patient dose in diagnostic radiology in Iran. A comprehensive literature search was performed without time constraints in the popular databases such as Google Scholar, Medline, Embase, PubMed, Irandoc, Iran Medex, Magiran and Scientific Information Database under the key words 'Entrance Surface Dose', 'dose area product, 'diagnostic reference level' and 'DRL' in Iran. Data on the radiation dose to patients has demonstrated further reductions in patient doses in the Iran. Considering advanced techniques and dose reduction methodologies complicates comparability between studies. Joint efforts of experts in the field of radiological protection and medical imaging and training program are necessary for achieving an acceptable condition.

Establishment of local diagnostic reference levels for abdomen and chest radiographies in the region of Algarve, Portugal

PURPOSE

To assess doses variabilities in the same abdomen and chest RX exams for adults, to check the need for dose harmonization. To calculate Diagnostic Reference Levels (DRL), mandatory in the European Union, for the Algarve district in Portugal. Our results can be a valuable reference for the Portuguese official determination of DRLs, still in progress.

METHOD

We considered 4,936 abdomen and 41,320 chest radiographs of adults, covering 7 health centres and 35 radiographers in Algarve. Entrance skin dose (ESD) was calculated for each radiograph and the corresponding uncertainty estimated. Mean doses per centre and per technician, and their uncertainties, were calculated to access dose variabilities. DRLs, set at the 3rd quartile of the total ESD distribution, were determined for a standard patient and for intervals of body mass index (BMI) to study their correlation with patient anatomical variations. Standard quartile errors were estimated.

RESULTS

Our results suggest significant dispersion in applied ESDs among different centres and radiographers. Estimates of DRLs also show small fluctuations across years and an important dependence on BMI intervals. For a standard patient, they are 8.7 ± 0.1 (abdomen) and 0.44 ± 0.01 (chest), while the European DRLs are, respectively, 5.1 and 0.2 (all in mGy).

CONCLUSIONS

Results suggest that there is room for dose optimization and harmonization with European DRLs, urging a national dose survey and the establishment of official national DRLs. Official DRLs in intervals of BMI would be quite beneficial, to avoid unnecessary dose exposures.

Estimates of Patient Radiation Doses in Digital Radiography Using DICOM Information at a Large Teaching Hospital in Oman

In this study, we sought to estimate the patient radiation doses in the digital radiography X-ray examinations conducted in a large hospital. The patient exposure factors and kerma-area product (PKA) were retrospectively recorded via the Digital Imaging and Communications in Medicine (DICOM) header for 547 patients. The entrance surface air kerma (ESAK) was estimated from the measurements of the X-ray tube output and recorded exposure factors, as well as from the console that displayed PKA as an alternative method. Effective doses were estimated from ESAK and PKA values using the appropriate conversion coefficient. In the chest PA, chest LAT, cervical spine AP, cervical spine LAT, abdomen AP, pelvis AP, lumbar spine AP, and lumbar spine LAT, the median ESAK (mGy) was found to be 0.13, 0.27, 0.35, 0.52, 0.70, 1.06, 2.33, and 4.18 mGy, respectively. Median PKA values were 0.10, 0.26, 0.14, 0.17, 0.77, 0.68, 0.81, and 1.11 Gy cm2, respectively. The estimated effective dose from ESAK and PKA values yielded comparable results. The comparison revealed that the ESAK and PKA values fell far below the reported in the literature. The results showed that the information of the DICOM deader is valuable for dosimetry and optimization.

COMPARISON OF RADIATION EXPOSURE TO THE PATIENT AND CONTRAST DETAIL RESOLUTIONS ACROSS LOW DOSE 2D/3D SLOT SCANNER AND TWO CONVENTIONAL DIGITAL RADIOGRAPHY X-RAY IMAGING SYSTEMS

PURPOSE

To assess and compare the radiation dose and image quality of the low dose 2D/3D EOS slot scanner (LDSS) to conventional digital radiography (DR) X-ray imaging systems for chest and knee examination protocols.

METHODS AND MATERIALS

The effective doses (ED) to the patient in the chest and knee clinical examination protocols for LDSS and DR X-ray imaging systems were determined using the dose area product and PCXMC Monte Carlo simulation software. The CDRAD phantom was imaged with 19 cm, and 13 cm thick Polymethyl Methacrylate (PMMA) blocks to simulate the chest and knees respectively of a patient of average adult size. The contrast detail resolution was calculated using image analysis software.

RESULTS

The EDs for the LDSS default setting were up to 69% and 51% lower than for the DR systems for the chest (speed 4) and knee (speed 6) protocols, respectively, while for the increased dose level setting then the EDs were up to 42% and 35% lower than for the DR systems for the chest (speed 6) and knee (speed 8) protocols respectively. At the default setting, the contrast detail was lowest for the default setting of the 2D/3D low dose slot scanner (LDSS) for both chest and knee examinations, but at the highest dose levels then the threshold were equal or higher than the contrast resolution of DR imaging systems.

CONCLUSION

The LDSS has the potential to be used for clinical diagnosis of chest and knee examinations using the higher dose level. For speed 6 in chest protocol and speed 8 in knee protocol, the measured contrast detail resolution was comparable with the DR systems but at a lower effective dose.

Patient dose measurement in common medical X-ray examinations and propose the first local dose reference levels to diagnostic radiology in Iran

Introduction: The main purpose of this study was to investigate patient dose in pelvic and abdomen x-ray examinations. This work also provided the LDRLs (local diagnostic reference levels) in Khuzestan region, southwest of Iran to help establish the NDRLs (national diagnostic reference levels).

Methods: Patient doses were assessed from patient’s anatomical data and exposure parameters based on the IAEA indirect dosimetry method. With regard to this method, exposure parameters such as tube output, kVp, mAs, FFD and patient anatomical data were used for calculating ESD (entrance skin dose) of patients. This study was conducted on 250 standard patients (50% men and 50% women) at eight high-patient-load imaging centers.

Results: The results indicate that mean ESDs for the both pelvic and abdomen examinations were lower than the IAEA and EC reference levels, 2.3 and 3.7 mGy, respectively. Mean applied kVps were 67 and 70 and mean FFDs were 103 and 109, respectively. Tube loadings obtained in this study for pelvic examination were lower than all the corresponding values in the reviewed literature. Likewise, the average annual patient load across all hospitals were more than 37000 patients, i.e. more than 100 patients a day.

Conclusions: The authors recommend that DRLs (diagnostic reference levels) obtained in this region, which are the first available data, can be used as local DRLs for pelvic and abdomen procedures. This work also provides that on-the-job training programs for staffs and close cross collaboration between physicists and physicians should be strongly considered.