Determination of Entrance Surface Dose of Digital Radiography for Adults at Public Medical Imaging Centers, Erbil

Introduction: Diagnostic X-ray is one of the ionizing radiations, the level of radiation dose received by the patient during medical examination is essential to prevent cancer risks. The aim of this study is to calculate entrance surface dose (ESD) and effective dose (ED) were estimated during chest, and lumber spine for adult patients in three hospitals in Erbil, using NOMEX MULTIMETER and PCXMC software. Material and Methods: The study was conducted in three public hospitals, in Erbil on (250) adult patients, whose ages between (18-70) years, based on the results study, ESD and ED were calculated for chest (PA, lateral), and lumbar spine (AP, lateral) examinations. NOMEX MULTIMETER (PTW, Freiburg), used in measurement of tube voltage, dose, dose rate, time product current, and total filtration automatically during examination. ED was calculated by using PCXMC software (version 2.5). Results: The results of this work are compared with published international literatures. The mean entrance skin dose for examinations of chest (PA, Lat), and lumber spine (AP, Lat) 1.02, 1.06, 2.61 and 3.92 mGy respectively. ED value was from 0.08, 0.19, 0.32, and 0.33 mSv, for chest (PA, Lat), and lumber spine (AP, Lat), respectively. Conclusion: The ESD, and ED were calculated in this work were found to be agreement with the published reference values for chest, and lumber spine set by international levels. ALARA principle should be considered by radiographer, to reduce absorbed dose of adults’ patient undergoing imaging radiography.

Measurement of Entrance Skin Dose in Radiographic Examinations of Pediatric Patients

Background: To measure the entrance skin dose in radiographic examinations of pediatric patients in King Khalid Hospital, Majmaah, Saudi Arabia Introduction: Children have been given special attention since they are often regarded as especially vulnerable to potential hazards. The pediatric population is more susceptible to radiation than the adult population for certain tumor types. Objective: The aim of this study is to determine the amount of Entrance Surface Dose (ESD) received by pediatric patients attending the emergency department. Method: Traumatic department registers for pediatric patients attending the King Khalid hospital (Majmaah, Saudi Arabia) between 1st February and 31st December 2018 were retrospectively studied for all diagnostic (plain radiographs examinations) imaging did on pediatric (<18 years old) trauma patients. The entrance surface dose was used to calculate the total radiation dose for each patient. One hundred and twenty patients encountered the inclusion criteria of the study, and their doses (chest, skull, and extremities) were assessed. Results: The mean of radiation exposure factors were 65.4 ± 7.9 (71.3 – 89.9) and 1.3 ± 0.2 (0.3–2.5) for X-ray tube potential (kVp) and current (mAs), respectively. The measured dose for pediatric patients were 0.10 ± 0.02 (0.09 – 0.37), 0.18 + 0.04 (0.06 -0.59) and 0.09 + 0.03 (0.03 -0.45) for chest, skull, and extremities, respectively. The mean Entrance surface dose received by trauma patients was 0.03-0.59 mGy. 51.7% (62 patients) of the patients received ≤ 0.25 mGy while around 48.3% (58 patients) received ≥ 0.26 mGy radiation dose from those examinations. Conclusion: Trauma patients attending to traumatic radiology department obtain substantial Entrance surface dose from chest, skull, and extremities imaging procedures within their initial assessment. The radiation exposure can also be lowered by optimizing each examination. Therefore more studies are recommended for this task. The results obtained can be used as the basis for local reference dosages for X-ray examinations.

Reduction of Ovarian Radiation Dose and Image Quality Disruptive Effects: New Constructed Shields for CT Scanning of Abdomen and Pelvis

Background: Cumulative dose of ovary as a radiosensitive organ during abdominal and pelvic CT scan imaging is still a controversial challenge that requires practical dose reduction strategies. Although bismuth shields can reduce the dose in the right proportions, their use is controversial due to the reduced image quality. Objectives: The aim of this study was to investigate the performance of a new combination of X-ray absorber structures that have less effect on image quality parameters. Methods: First, various shields with different weight percentages of Cu and Bi were made, then the percentage of dose reduction and image quality were evaluated via phantoms. Finally, Shield with the least effect on image quality was evaluated for clinical evaluation on 20 patients. Results: Shielding with thicknesses of 1T and 3T reduced the Entrance skin dose of ovarian by about 52% and 73%, respectively. Shields with 90% cu-10% Bi and 100% Bi structures had the least and most destructive effects on image quality, respectively, and also have the same image quality. The 10% Bi-90% Cu shield provided a 21% greater dose reduction than the bismuth shield. Also, this 1T thick shield did not create an artifact in the reconstructed images. Conclusions: Shields are flexible, inexpensive, and user-friendly for ovarian shielding in abdominal and pelvic CT scans. Unlike bismuth shields, shields do not have the detrimental effects of image quality degradation.

Image Quality and Radiation Dose for Fibrofatty Breast using Target/filter Combinations in Two Digital Mammography Systems

Objectives: The aim of this study was to determine the optimum combinations of target and filter materials for various X-ray tube voltage settings, as well as their effects on image quality and radiation dose. This was done using different digital mammography (DM) imaging systems with a breast equivalent phantom. Material and Methods: Two DM units with a tungsten (W) target, silver (Ag), and rhodium (Rh) filters and dual molybdenum (Mo) and Rh targets/filters were used. A tissue-equivalent mammography phantom of 6 cm thickness equivalent to a fibrofatty breast was exposed 20 times to different target/filter material combinations (W/Rh, W/Ag, Rh/Rh, Mo/Rh, and Mo/Mo) and various kV settings (28–34 kV). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for each exposure. Results: The W/Ag combination resulted in the lowest entrance skin dose and mean glandular dose (MGD). The MGD for the W/Rh combination was 60% less than that of the W/Ag combination at 34 kV (P < 0.05). There was a direct relationship in the SNR with the Mo/Mo, Mo/Rh, and Rh/Rh combinations and an inverse relationship with the CNR in the 34 kV range. There were statistically significant differences between all five target/filter combinations, and the best SNR and CNR were observed for the W/Rh combination with a reduced radiation dose in the range of 28–30 kV (P < 0.05). Conclusion: For a breast thicknesses of 6 cm with a fibrofatty nature, the W/Rh combination delivers high performance in terms of image quality at a lower dose.

REDUCING ABSORBED DOSE TO THYROID IN NECK CT EXAMINATIONS: THE EFFECTS OF SABA SHIELDING

Bi shielding has been used for the protection of radiosensitive organs during computed tomography (CT) for 20 years. In 2017, American Association of Physicists in Medicine recommended against Bi shielding due to its degrading effects on image quality. Saba shielding introduced recently protecting organs as Bi shielding without degrading image quality. In this study, the Saba shield was modified and primary radiation attenuation values of the shields and entrance skin dose (ESD) on the thyroid were measured with and without shielding. Furthermore, the quality of images obtained using Saba shielding was investigated quantitatively and qualitatively. Saba and Bi shielding reduced the ESD on the thyroid by about 50%. Saba shielding had about 5–7 HU less noise and about 51–65 HU less CT numbers shift in comparison with Bi shielding at a distance of 1 cm from the shields. Saba shielding had no degrading effects on image quality in the patient study.

Radiation exposure of interventional cardiologists for different types of procedures in catheterization lab, is it more concern about extremities?

Introduction: Angiography and angioplasty expose cardiologists to a high level of X-ray comparing other radiographic methods, due to the high dose of radiation and the presence of the physician beside the patient bed during the procedure. Therefore, this study was designed to measure the absorbed dose in some important organs and extremities in cardiologists during different angiography and angioplasty procedures in catheterization lab. Methods: The entrance skin dose and extremity absorbed dose of the physicians in 100 angiography and angioplasty procedures were measured by TLD chips. The points on the physicians’ body, which were measured in this study, included: thyroid, right and left chest, right and left wrists, and left leg. The correlation of entrance skin dose in these six points to the exposure parameters is also evaluated. Results: The left leg has maximum dose and maximum correlation with total DAP for all three physicians in all procedure types. There was a weak correlation between left wrist absorbed dose and number of views among three physicians. Also, the maximum annual absorbed dose of the physicians in the left leg was lower than 150 mSv. Conclusion: According to the results of this study, it can be stated that periodic leg and hand dosimetry during operation is necessary for interventional cardiologists. Results also showed that, regardless of the type of procedure, the characteristics of device output, especially DAP, have a direct role in the absorbed dose of the organs and extremities, especially those outside the shield.