Errors in Patient Positioning for Bone Mineral Density Assessment by Dual X-Ray Absorptiometry: Effect of Technologist Retraining

Improper positioning is one of the factors that can lead to incorrect bone mineral density (BMD) results. This study aimed to assess the frequencies of erroneous positioning during three periods: before retraining of the technologists (BR), after retraining (AR), and at the current timepoint 8 years after retraining (C). The BMD images of the first 150 consecutive patients who underwent DXA of the lumbar spine and hip during each of the three periods were retrospectively reviewed. Patients were excluded if they had severe scoliosis, rendering proper positioning impossible. Each BMD image was assessed by an International Society of Clinical Densitometry certified clinical densitometrist who was blinded to the date of the initial examination. For the lumbar spine in the BR group, the criteria frequently not met were inclusion of both iliac crests (33.8%), straightness (30.3%), and midline positioning (20.4%); the respective frequencies were significantly reduced to 0.8%?5.6%, 2.1%?3.0%, and 0%?2.8% in the AR and C groups (p < 0.05). For the hip in the BR group, the criteria frequently not met were straightness (52.8%) and internal rotation (21.8%); the respective frequencies were significantly reduced to 0%?4.2% and 8.3%?8.4% in the AR and C groups (p < 0.05). Overall improper positioning in the BR group was 49.3% and 57.3% at the lumbar spine and the hip, respectively; the respective frequencies were reduced to 9.3% and 12.7% in the AR group, and to 2.7% and 7.3% in the C group. The least significant change values for the lumbar spine, femoral neck, and total hip also became smaller after retraining. Retraining the technologists improved patient positioning, as evidenced by the decreased frequencies of erroneous positioning and the improved least significant change values after the retraining.     

Development of a lyophilized soybean paste certified reference material for the analysis of ochratoxin A

A certified reference material (CRM) [²KRISS CRM # 108-10-018] for the analysis of ochratoxin A (OTA) in doenjang (fermented soybean paste and popular food in Korea) was produced to ensure the reliability of analytical results in testing laboratories. A home-made doenjang was chosen as a raw material after testing its OTA level. The raw material was freeze-dried, pulverized, sieved and homogenized. An isotope-dilution-liquid chromatography/tandem mass spectrometric method (ID-LC/MS/MS) which was previously developed and validated in this laboratory was used as a higher-order reference method for characterization, homogeneity studies, and short-term stability studies. The CRM had good between-bottle homogeneity with 0.56% relative standard deviation among 10 selected units. The stability of the CRM at −70 °C (the storage condition in our laboratory) and at −20 °C (the possible storage temperature at user sites) were tested for up to 8 months. No change in the OTA content was observed within the measurement uncertainty. The stability of the CRM at room temperature (for regular use and transportation) was also tested and confirmed. The certified value was (49.50 ± 1.17) μg/kg, where the expanded uncertainty was in the confidence level of 95%.     

Image Fusion of Real-Time Ultrasonography with Computed Tomography: Factors Affecting the Registration Error and Motion of Focal Hepatic Lesions

Factors affecting the registration error (RE) and motion of focal hepatic lesions (FHLs) in image fusion of real-time ultrasonography (US) with computed tomography (CT) images were prospectively assessed by focusing on respiratory movement and FHL location. Real-time US and pre-acquired CT images at end-inspiration were fused with FHLs for 103 patients. Three-dimensional US data containing FHLs were obtained during end-inspiratory/expiratory phases. Multivariate analysis revealed that diaphragm motion (p < 0.001), chronic liver disease (p = 0.02) and the absolute difference in distance between the FHL and the central portal vein (CPV) during respiration (p = 0.03) were the independent factors that revealed the maximum effect on RE. In contrast, diaphragm motion (p < 0.001) and distance between the FHL and CPV at inspiration (p = 0.036) revealed the maximum effect on FHL motion. In conclusion, RE and FHL motion are affected by the degree of respiratory movement and the location of the FHL. Therefore, image fusion with CT images should be used with caution if the degree of respiratory motion is significant or if the FHL is located at the periphery of the liver.     

The dosimetric impact of respiratory breast movement and daily setup error on tangential whole breast irradiation using conventional wedge,field-in-field and irregular surface compensator techniques

To evaluate the dosimetric impact of respiratory breast motion and daily setup error on whole breast irradiation (WBI) using three irradiation techniques; conventional wedge (CW), field-in-field (FIF) and irregular surface compensator (ISC). WBI was planned for 16 breast cancer patients. The dose indices for evaluated clinical target volume (CTV_evl), lung, and body were evaluated. For the anterior-posterior (AP) respiratory motion and setup error of a single fraction, the isocenter was moved according to a sine function, and the dose indices were averaged over one period. Furthermore, the dose indices were weighted according to setup error frequencies that have a normal distribution to model systematic and random setup error for the entire treatment course. In all irradiation techniques, AP movement has a significant impact on dose distribution. CTV_evlD₉₅ (the minimum relative dose that covers 95 % volume) and V₉₅ (the relative volume receiving 95 % of the prescribed dose) were observed to significantly decrease from the original ISC plan when simulated for the entire treatment course. In contrast, the D₉₅, V₉₅ and dose homogeneity index did not significantly differ from those of the original plans for FIF and CW. With regard to lung dose, the effect of motion was very similar among all three techniques. The dosimetric impact of AP respiratory breast motion and setup error was largest for the ISC technique, and the second greatest effect was observed with the FIF technique. However, these variations are relatively small.     

Reliability of Auditory Function Tests in Severely Hearing-Impaired and Deaf Subjects

The test-retest variability of a series of auditory functions has been investigated in a group of severely hearing-impaired and deaf subjects (64 ears, median Fletcher index: 80 dB) and in a group of 10 controls with normal hearing. An adaptive forced-choice procedure was used for both groups. The functions were: tone audiogram, difference limen for intensity, difference limen for frequency, modulation transfer function and critical ratio. In spite of sometimes strongly deviating function values within the hearing-impaired group, the test-retest variability of the two groups was found to be of the same order of magnitude, except for the tone audiogram where the variability in the hearing-impaired group was twice that for the control group.

Nous avons examiné la variabilité des mesures répétées de quelques fonctions auditives dans un groupe de sujets ayant des troubles auditifs importants (64 oreilles; médiane de l'index de Fletcher 80 dB). Par comparaison nous avons aussi examiné un groupe de 10 sujets ayant une audition normale. Dans les deux groupes nous avons utilisé une procédure adaptive et de choix forcé. Nous avons examiné les seuils auditifs, les seuils différentiels d'intensité et de fréquence, la fonction de transfert de modulation et le rapport critique. Malgré les anomalies majeures du groupe des malentendants, la variabilité des mesures dans les deux groupes est équivalente, à l'exception de la variabilité des seuils auditifs qui est deux fois plus grande chez les malentendants.     

What about doctors? The impact of medical errors

Medical error is a distressing event to the patient and the health care providers. The impact of such events has been well studied on patients but poorly on health professionals. These events are still considered as a taboo in the medical culture and hence missed as great learning opportunities. They have negative impact on doctors' emotional wellbeing, general quality of life, and their professional practice and conduct. Medical errors and adverse events also affect the quality and cost of the health service. Health service administrations should provide healthcare professionals involved in such events with professional support and counselling services, and should consider and treat them as second victims.