Computed tomography tissue equivalence of 3D printing materials.

INTRODUCTION: Additive production refers to the process of prototyping, which allows the production of highly complex medical devices and products. Interpretation of additive manufacturing (AM) material in Computed Tomography (CT) has not been widely investigated. The aim of this study was to determine the CT number values of commercially available fused deposition modelling (FDM) and stereolithography (SLA) AM materials. METHODS: Total of 15 AM materials, 7 FMD and 8 SLA, were selected and scanned on CT to determine the HU value and appearance on the images. All test object were designed as rectangular blocks and after their production physical description were calculated. AM materials were scanned on CT operating at 80, 100, 120 and 135 kV. RESULTS: All materials correspond to a certain human tissue and they have uniformity when printed with 100% infill. CT number ranged from a minimum of -188.0 HU to a maximum of 189.1 HU, for FDM materials, and from -15.8 HU to 167.3 HU, for SLA materials. CONCLUSION: Knowing the CT number of an AM materials can allow the design of medical or rehabilitation products with a specific appearance on CT images. Analysed and collected data can find application in the design and manufacture of immobilization devices that can be easily distinguished from other materials or human tissue. IMPLICATIONS FOR PRACTICE: This study provides information that can be used in the design and fabrication of anthropomorphic diagnostic and therapeutic phantoms. There is significant potential for the use of AM material for sophisticated test objects when used in medical image modality testing. Knowing actual CT numbers of frequently used AM materials allows manufacturing anthropomorphic phantoms to investigate radiation doses in diagnostic radiology and radiotherapy.

[Intermittent flank pain]. / Intermitterende flankpijn.

Flank pain is a common problem that can be caused by a variety of abnormalities. In this case report we describe two patients with intermittent flank pain with an unusual cause: intermittent ureteropelvic junction obstruction due to crossing of accessory renal vessels. Instant imaging at the time when the symptoms occur seems the best way to prevent delays in diagnosis and treatment.

Occupational exposure doses in interventional procedures in Bosnia and Herzegovina.

Monitoring of occupationally exposed workers in Bosnia and Herzegovina started in 1960s and it was interrupted in 1992. Dosimetry service resumed in 1999 when the International Atomic Energy Agency provided Radiation Protection Centre with Harshaw 4500 Thermoluminescence dosemeter (TLD)-reader and the first set of TLDs. The highest doses are received by professionals working in interventional procedures (radiology, cardiology, gastroenterohepatology etc.). Number of these procedures is increasing each year (just in cardiology this increase is 24 % per year). Results from two TLDs are used to estimate effective dose. One is worn under the apron (chest level), and the other above (neck level). Calculation is performed using Niklason's methodology. Total number of occupationally exposed persons in interventional radiology is 90. The collective dose they receive is 67 person mSv, while the mean dose is 0.77 mSv (based on 12-month period). Highest doses are received by physicians (3.7 mSv), while radiographers and nurses receive 2.1 and 1.9 mSv respectively. This occurs due to the fact that physicians stand closer to the source (patient). The lead apron is proven to be the most efficient radiation protection equipment, but, also, lead thyroid shield and glasses can significantly lower doses received by professionals. The use of this equipment is highly recommended.

Status of radiation protection in interventional cardiology in four East European countries.

Level of staff and patient radiation protection in interventional cardiology in four counties (Bosnia and Herzegovina, Croatia, Montenegro and Serbia) as a part of International Atomic Energy Agency project (RER/9/093) are presented. Patient doses were assessed in terms of air kerma area product (KAP), peak skin dose (PSD) or air kerma at interventional reference point (K(IRP)). Results were available from nine hospitals: 775 patients for KAP, 157 for PSD and 437 for K(IRP). Eight centres reported KAP >100 Gy cm(2) and five centres reported values >200 Gy cm(2). From patients monitored in terms of PSD, 14 (9 %) had PSD >2 Gy and 6 (3 %) patients from those monitored in terms of K(IRP) had value >5 Gy, indicating risk of skin injury. The results indicate need for optimisation and dose monitoring in complex fluoroscopically guided cardiology interventions.

Occupational and patient exposure in interventional cardiology in Bosnia and Herzegovina.

Monitoring of professionally exposed workers in Bosnia and Herzegovina started in 1960s. Doses received by patients and professionals in interventional cardiology are high in comparison with other practices in medicine. The purpose of this study is to present personal and patient dosimetry data. Results show increase in doses of personnel in interventional cardiology. Total collective dose for four cardiology centres in Bosnia and Herzegovina increased from 15 person mSv in 2007 to 52 person mSv in 2010. This increase mainly corresponds to higher number of personnel and increase in the number of procedures. Average monthly dose has increased from 0.40 to 0.72 mSv in the same period. The results of occupational and patient doses in interventional cardiology are similar to results reported in the literature. It is of great importance for professionals working in this field to be educated in radiation protection and proper use of X-ray equipment.

Ten years of monitoring the occupational radiation exposure in Bosnia and Herzegovina.

Monitoring of occupationally exposed persons in Bosnia and Herzegovina started in 1960s and it was interrupted in 1992. Dosimetry service resumed in 1999 when the International Atomic Energy Agency provided Harshaw 4500 TLD-reader and the first set of TLDs for the Radiation Protection Centre (RPC) of the Institute of Public Health of the Federation of Bosnia and Herzegovina. In January 2009, the RPC covered 1279 professionals with personal dosimetry, which is more than 70 % of all radiation workers in the country. Most of the TLD users work in medical institutions. In period 1999-2003 RPC provided 984 workers with dosemeters. In the next 5 y period (2004-2008), the number of persons covered by dosimetry increased by an average of 51 %. The mean and collective effective dose in the period 1999-2003 were 1.55 mSv and 1.54 personSv, respectively. In the period 2004-2008, the mean doses changed by 1 % on average, but the collective effective dose increased by 53 % for all practices. Mean and collective effective dose were 1.57 mSv and 2.34 personSv, respectively. The highest personal doses are associated with industrial radiography, than exposures in nuclear medicine. Radiology plays a significant role in collective dose only, whereas other exposures are low. Results correspond to results found in the literature. New practices in industry and medicine emphasise the need for more personal dosemeters, as well as specialised dosemeters for extremities monitoring, etc.

Paediatric CT examinations in 19 developing countries: frequency and radiation dose.

The aims of this study were to investigate the frequency of computed tomography (CT) examinations for paediatric patients below 15 y of age in 128 CT facilities in 28 developing countries of Africa, Asia and Eastern Europe and to assess the magnitude of CT doses. Radiation dose data were available from 101 CT facilities in 19 countries. The dose assessment was performed in terms of weighted CT dose index (CTDI(w)), volume CT index and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. The results show that on average the frequency of paediatric CT examinations was 20, 16 and 5 % of all CT examinations in participating centres in Africa, Asia and Eastern Europe, respectively. Eleven CT facilities in six countries were found to use adult CT exposure parameters for paediatric patients, thus indicating limited awareness and the need for optimisation. CT images were of adequate quality for diagnosis. The CTDI(w) variations ranged up to a factor of 55 (Africa), 16.3 (Asia) and 6.6 (Eastern Europe). The corresponding DLP variations ranged by a factor of 10, 20 and 8, respectively. Generally, the CTDI(w) and DLP values in Japan are lower than the corresponding values in the three regions in this study. The study has indicated a stronger need in many developing countries to justify CT examinations in children and their optimisation. Awareness, training and monitoring of radiation doses is needed as a way forwards.

Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects.

The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs. The resulting CT images were of adequate quality for diagnosis. The CTDIw and DLP data presented herein are largely similar to those from two recent national surveys. The study has shown a stronger need to create awareness and training of radiology personnel as well as monitoring of radiation doses in many developing countries so as to conform to the ALARA principle.