Radiation Exposure in Bone Densitometry.

This article provides an overview of the literature regarding the magnitude of radiation exposure associated with the current radiologic methods used in patients with suspected osteoporosis. The use of X-ray-based techniques for the detection and monitoring of osteoporosis has increased over the last few decades. Dual-energy X-ray absorptiometry is the most common method, used worldwide for the assessment of osteoporosis, and it may be applied at several skeletal sites. Quantitative computed tomography comprises an alternative validated technique, increasingly used for skeleton assessment. Although radiation doses from methods applied for the management of osteoporosis are low, compared with other radiologic methods, special attention should be paid to justify and optimize each procedure, taking into consideration all radiation protection measures. Dose optimization, including dose reduction techniques and low-dose protocols, is of paramount importance, even for low-dose examinations, to achieve the minimum radiation burden to the exposed patients and personnel.

Data and methods to estimate fetal dose from fluoroscopically guided prophylactic hypogastric artery balloon occlusion.

PURPOSE: To provide data for estimation of fetal radiation dose (DF) from prophylactic hypogastric artery balloon occlusion (HABO) procedures. METHODS: The Monte-Carlo-N-particle (MCNP) transport code and mathematical phantoms representing a pregnant patient at the ninth month of gestation were employed. PA, RAO 20° and LAO 20° fluoroscopy projections of left and right internal iliac arteries were simulated. Projection-specific normalized fetal dose (NFD) data were produced for various beam qualities. The effects of projection angle, x-ray field location relative to the fetus, field size, maternal body size, and fetal size on NFD were investigated. Presented NFD values were compared to corresponding values derived using a physical anthropomorphic phantom simulating pregnancy at the third trimester and thermoluminescence dosimeters. RESULTS: NFD did not considerably vary when projection angle was altered by ±5°, whereas it was found to markedly depend on tube voltage, filtration, x-ray field location and size, and maternal body size. Differences in NFD < 7.5% were observed for naturally expected variations in fetal size. A difference of less than 13.5% was observed between NFD values estimated by MCNP and direct measurements. CONCLUSIONS: Data and methods provided allow for reliable estimation of radiation burden to the fetus from HABO.

Abdominal CT during pregnancy: a phantom study on the effect of patient centring on conceptus radiation dose and image quality.

OBJECTIVES: To investigate the effect of patient centring on conceptus radiation dose and image quality in abdominal CT during pregnancy. MATERIAL AND METHODS: Three anthropomorphic phantoms that represent a pregnant woman at the three trimesters of gestation were subjected to a routine abdominal CT. Examinations were performed with fixed mAs (mAsf) and with the automatic exposure control system (AEC) activated. The percent reduction between mAsf and modulated mAs (mAsmod) was calculated. Conceptus dose (Dc) was measured using thermoluminencent dosimeters. To study the effect of misplacement of pregnant women on Dc, each phantom was positioned at various locations relative to gantry isocentre. Image quality was evaluated on the basis of image noise, signal-to-noise ratio, and contrast-to-noise ratio. RESULTS: The maximum reduction between mAsf and mAsmod was 59.8 %, while the corresponding DC reduction was 59.3 %. DC was found to decrease by up to 25 % and 7.9 % for phantom locations below and above the isocentre, respectively. Image quality deteriorated when AEC was activated, and it was progressively improved from lower to higher than the isocentre locations. CONCLUSION: Centring errors do not result in an increase in Dc. To maintain image quality, accurate centring is required. KEY POINTS: • AEC activation reduces conceptus radiation dose at all gestational stages. • Patients should be accurately aligned at the gantry isocenter. • Patient centring deserves increased attention in clinical practice. • Pregnant patient centring errors do not considerably affect conceptus dose.

Pediatric radiation dose and risk from bone density measurements using a GE Lunar Prodigy scanner.

UNLABELLED: Effective radiation doses associated with bone mineral density examinations performed on children using a GE Lunar Prodigy fan-beam dual-energy X-ray absorptiometry (DXA) scanner were found to be comparable to doses from pencil-beam DXA devices, i.e., lower than 1 µSv. Cancer risks associated with acquisitions obtained in this study are negligible. INTRODUCTION: No data were found in the literature on radiation doses and potential risks following pediatric DXA performed on GE Lunar DXA scanners. This study aimed to estimate effective doses and associated cancer risks involved in pediatric examinations performed on a GE Lunar Prodigy scanner. METHODS: Four physical anthropomorphic phantoms representing newborn, 1-, 5-, and 10-year-old patients were employed to simulate DXA exposures. All acquisitions were carried out using the Prodigy scanner. Dose measurements were performed for spine and dual femur using the phantoms simulating the 5- and 10-year-old child. Moreover, doses associated with whole-body examinations were measured for the four phantoms used in the current study. RESULTS: The gender-average effective dose for spine and hip examinations were 0.65 and 0.36 µSv, respectively, for the phantom representing the 5-year-old child and 0.93 and 0.205 µSv, respectively, for the phantom representing the 10-year-old child. Effective doses for whole-body examinations were 0.25, 0.22, 0.19, and 0.15 µSv for the neonate, 1-, 5-, and 10-year old child, respectively. The estimated lifetime cancer risks were negligible, i.e., 0.02-0.25 per million, depending on the sex, age, and type of DXA examination. A formula is presented for the estimation of effective dose from examinations performed on GE Lunar Prodigy scanners installed in other institutions. CONCLUSIONS: The effective doses and potential cancer risks associated with pediatric DXA examinations performed on a GE Lunar Prodigy fan-beam scanner were found to be comparable to doses and risks reported from pencil-beam DXA devices.

Quality assurance of imaging techniques used in the clinical management of osteoporosis.

Recent advances in the densitometric and imaging techniques involved in the management of osteoporosis are associated with increasing accuracy and precision as well as with higher exposure to ionising radiation. Therefore, special attention to quality assurance (QA) procedures is needed in this field. The development of effective and efficient QA programmes is mandatory to guarantee optimal image quality while reducing radiation exposure levels to the ALARA principle (as low as reasonably achievable). In this review article, the basic QA procedures are discussed for the techniques applied to everyday clinical practice.

Subclavian vein flexible guidewire knotting. A potential serious complication in hemodialysis patients.

BACKGROUND: Complications after subclavian vein catheterization are well-documented in the literature. The purpose of this article is to present a case of a rare and potential serious complication of flexible guidewire knotting in subclavian vein catheterization in a hemodialysis patient. METHOD: A 72 year-old woman on hemodialysis due to diabetes has had left upper extremity arteriovenous fistula (AV-F) thrombosed on the scheduled hemodialysis day. A right subclavian vein catheterization for hemodialysis was decided and attempted, that ended up with a flexible guidewire knotting. RESULTS: The flexible guidewire was splinted with the Kit's dilator and after great effort, under radioscopic control the knotting was managed to be unknotted and the guidewire removed. CONCLUSIONS: Our case suggests that a rare and potential serious complication of subclavian vein catheterization for hemodialysis can be successfully managed with appropriate approach and skillful maneuvers.

Relief of the pain of unresectable carcinoma of pancreas by chemical splanchnicectomy during laparotomy.

Peroperative chemical splanchnicectomy using 5% phenol in almond oil is an effective method of relieving pain in carcinoma of the pancreas. Forty-nine patients have been treated, 41 having suffered preoperative pain. Five patients died within 10 days of operation, but in no case was the splanchnicectomy a contributing factor. Of the 37 patients who had suffered pain preoperatively and then survived 10 days or more after operation, 30 (81%) experienced relief of pain and in 26 (70%) this relief persisted till death. There was no statistically significant difference in survival patterns of these splanchnicectomy patients and a comparable group of patients with pancreatic carcinoma treated in a similar way but without splanchnicectomy.