Calculated Radiation Exposure Research Articles

Microgroove etching on flexible copper clad laminate with picosecond lasers

Liquid crystal polymers (LCPs) have received extensive attention in the field of 5G electronic device packaging because of their high performance as microwave substrates and packaging materials. This article describes the use of a two-wavelength picosecond laser, with a pulse duration of 8.8 ps and a repetition frequency of 100 kHz, to perform ablation experiments on a flexible LCP copper clad laminate. By fitting the experimental results, the calculated radiation exposure was found to be 3.1 and 4.45 J/cm2 at wavelengths of 1064 and 355 nm, respectively. In addition, it was revealed that the laser parameters and the material characteristics of the LCP seriously affected the quality of laser machining due to photopolymerization of the LCP at 1064 nm; in contrast, better results were obtained at 355 nm. Furthermore, the effect of scanning speed and average power on the microgroove etching process was investigated. Desirable etching results were obtained at a scanning speed of 500–700 mm/s and an average power of 2.5–3.5 W. The results of this study can be useful for the processing of LCP-encapsulated electronic devices.

Feasibility of 18F-FDG Dose Reductions in Breast Cancer PET/MRI.

The goal of this study was to determine the level of clinically acceptable 18F-FDG dose reduction in time-of-flight PET/MRI in patients with breast cancer. Methods: Twenty-six consecutive women with histologically proven breast cancer were analyzed (median age, 51 y; range, 34-83 y). Simulated dose-reduced PET images were generated by unlisting the list-mode data on PET/MRI. The acquired 20-min PET frame was reconstructed in 5 ways: a reconstruction of the first 2 min with 3 iterations and 28 subsets for reference, and reconstructions simulating 100%, 20%, 10%, and 5% of the original dose. General image quality and artifacts, image sharpness, image noise, and lesion detectability were analyzed using a 4-point scale. Qualitative parameters were compared using the nonparametric Friedman test for multiple samples and the Wilcoxon signed-rank test for paired samples. Different groups of independent samples were compared using the Mann-Whitney U test. Results: Overall, 355 lesions (71 lesions with 5 different reconstructions each) were evaluated. The 20-min reconstruction with 100% injected dose showed the best results in all categories. For general image quality and artifacts, image sharpness, and noise, the reconstructions with a simulated dose of 20% and 10% were significantly better than the 2-min reconstructions (P ≤ 0.001). Furthermore, 20%, 10%, and 5% reconstructions did not yield results different from those of the 2-min reconstruction for detectability of the primary lesion. For 10% of the injected dose, a calculated mean dose of 22.6 ± 5.5 MBq (range, 17.9-36.9 MBq) would have been applied, resulting in an estimated whole-body radiation burden of 0.5 ± 0.1 mSv (range, 0.4-0.7 mSv). Conclusion: Ten percent of the standard dose of 18F-FDG (reduction of ≤90%) results in clinically acceptable PET image quality in time-of-flight PET/MRI. The calculated radiation exposure would be comparable to the effective dose of a single digital mammogram. A reduction of radiation burden to this level might justify partial-body examinations with PET/MRI for dedicated indications.

Surveillance imaging and radiation exposure in the detection of relapsed neuroblastoma.

More than half of children with high-risk neuroblastoma (NB) will experience recurrence. Radiologic imaging is used for initial staging and during therapy to assess response. However, the role of surveillance imaging in the detection of relapse has not been well studied. Surveillance potentially results in high cumulative exposure to ionizing radiation, which may be associated with an increased risk of developing second malignancies. We reviewed NB cases at our institution between 2000 and 2011. We calculated radiation exposure due to imaging (during diagnosis, treatment, and posttherapy surveillance) using cumulative effective dose (CED) estimates and determined whether cross-sectional imaging identified recurrences. Fifty of 183 patients with NB experienced a recurrence. The median time from diagnosis to relapse was 1.20 years (range: 0.18-6.66 years). Most patients had evidence of metastases and only 4 of 50 patients presented with isolated primary tumor site recurrences. The mean CED prior to relapse was 125.2 mSv (range: 24.5-259.7), 64% of which was from computed tomography (CT) scans. Thirty-seven of 50 patients had clinically evident or measurable disease detected by X-ray (XR), ultrasound (US), or urinary catecholamines (UCats), and the addition of metaiodobenzylguanidine (MIBG) scans identified eight additional recurrences. Thus, cross-sectional imaging (CT/MRI, where MRI is magnetic resonance imaging) was only required to identify 10% (5/50) of cases. Relapsed disease was detected in most patients by symptoms/exam, MIBG scan, UCats, and/or XR/US, supporting reduced use of CT imaging in posttherapy surveillance, thereby decreasing cumulative radiation dose. Refinement of surveillance imaging may be further guided by risk stratification, disease sites, and potentially biomolecular markers.

Patient radiation exposure during transforaminal lumbar endoscopic spine surgery: a prospective study.

OBJECTIVE The aim of this study was to describe patient radiation exposure during single-level transforaminal endoscopic lumbar discectomy procedures at levels L2-5 and L5-S1. METHODS Radiation exposure was monitored in 151 consecutive patients undergoing single-level transforaminal endoscopic lumbar discectomy procedures. Two groups were studied: patients undergoing procedures at the L4-5 level or above and those undergoing an L5-S1 procedure. RESULTS For the discectomy procedures at L4-5 and above, the average duration of fluoroscopy was 38.4 seconds and the mean calculated patient radiation exposure dose was 1.5 mSv. For the L5-S1 procedures, average fluoroscopy time was 54.6 seconds and the mean calculated radiation exposure dose was 2.1 mSv. The average patient radiation exposure dose among these cases represents a 3.5-fold decrease compared with the senior surgeon's first 100 cases. CONCLUSIONS Transforaminal lumbar endoscopic discectomy can be used as a minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a herniated lumbar disc without the significant concern of exposing the patient to harmful doses of radiation. One caveat is that both the surgeon and the patient are likely to be exposed to higher doses of radiation during a surgeon's early experience in minimally invasive endoscopic spine surgery.

Calculated radiation exposure for trauma patients is lower when using the new injury severity score (NISS) when compared to the injury severity score (ISS) to calculate injury severity

Calculated radiation exposure for trauma patients is lower when using the new injury severity score (NISS) when compared to the injury severity score (ISS) to calculate injury severity

Calculated radiation exposure for trauma patients is lower when using the New Injury Severity Score versus the Injury Severity Score to calculate injury severity

We studied radiation exposure (RE) in trauma patients [1]. To adjust for injury severity the New Injury Severity Score (NISS) or the Injury Severity Score (ISS) can be used to group patients. We sought to determine whether there is a difference in the calculated RE per group when the patients are grouped using either the NISS or ISS.

Detection of bodypacks: Accuracy of abdominal radiography versus very low dose CT

Purpose The aim of this study was to investigate the detectability of bodypacks in low dose computed tomography (CT) in comparison to abdominal radiography (AR). Materials and method Bodypacks ( n =13 to n =20 per body) were placed into the small intestines of 9 human corpses. In each case AR and CT at different dose levels were performed: standard dose for abdominal CT scans (CTDI=8.5 mGy/cm), 1/2 dose (CTDI=4.3 mGy/cm), 1/4 dose (CTDI=2.1 mGy/cm), 1/8 dose (CTDI=1.1 mGy/cm), 1/16 dose (CTDI=0.6 mGy/cm), and technical minimal dose of 1/60 (CTDI=0.14 mGy/cm). Two independent observers counted the number of bodypacks in each CT dataset and in the AR. Radiation exposure was estimated for CT using the dose-length-product and for AR using the area-dose-product. Results Intra- and interobserver agreement was good. Image noise at CT ranged between 17 HU (at standard dose) and 300 HU (at technical minimal dose). At AR, the accuracy for the detection of bodypacks had a sensitivity of 59% and a specificity of 97% at an average radiation exposure of 1.0 mSv. In CT, all bodypacks were detected at every dose level (sensitivity and specificity: 100%). The calculated radiation exposure ranged from 10.9 mSv (at standard dose) to 0.2 mSv (at technical minimal dose). Discussion CT permits detection of all bodypacks even at minimal dose levels of 0.2 mSv. Therefore, the use of very low-dose CT is recommendable for the detection of bodypacks in suspected traffickers as low-dose CT provides a superior accuracy and a lower radiation exposure than AR.

Operative Fixation of Acetabular Fractures in the Pregnant Patient

To describe in utero radiation exposures in pregnant patients undergoing acetabular fracture repair. Retrospective case series. University-affiliated regional trauma center. Eight pregnant patients with acetabular fractures treated over a 6-year period. There were an additional 518 acetabular fractures in nonpregnant patients treated during the same time period. Open reduction and internal fixation of the acetabulum fracture. None. This is a descriptive series reporting fetal radiation doses, fetal fluoroscopy exposure times, and fetal viability after treatment. The gestational age of the fetuses at presentation ranged from 5 to 26 weeks. Infant delivery averaged 27 weeks from the time of surgery and all pregnancies reached 36 weeks. Apgar scores were normal each child including 1 twin delivery. There were 4 posterior wall fractures, 3 transverse or posterior wall fractures, and 1 posterior column fracture. Intraoperative pelvic fluoroscopy averaged 39 seconds. There were no operative complications and fracture reductions were anatomic in 7 patients. Computed tomography scan of the pelvis conferred the greatest exposure risk to the fetus and fluoroscopy conferred the least. In each case that required a computed tomography scan of the pelvis, the calculated radiation exposure dose to the fetus was greater than 5 cGy. The results of this study demonstrate that with a team approach and the judicious use of radiographic imaging during the surgical care of a displaced acetabular fracture in the pregnant patient, minimal risk to the baby can be achieved in pursuit of acceptable articular reductions.

Radiation doses deriving from patients treated with 166Ho-ferric hydroxide

To estimate radiation doses deriving from patients treated with (166)Ho ferric hydroxide. For radiation synoviorthesis about 900 +/- 100 MBq (166)Ho ferric hydroxide was injected into the knee joint of 16 patients. To estimate the radiation exposure of persons in the neighbourhood of the patients measurements of the dose rates were performed at 0.5 m, 1 m and 2 m distance of the treated joint 10 min after tracer injection. Measurements were carried out with and without radiation protection devices of the syringe. The initial values of the dose rate were 11.9 micro Sv/h at 0.5 m, 3.5 micro Sv/h at 1 m and 1 micro Sv/h at 2 m distance, respectively. The whole body doses were 2.9 micro Sv for the physician and 4.6 micro Sv for the technologist. The finger doses for the technologist and the physician were ranging from 65 to 111 micro Sv. After discharge at home other persons might receive 118 micro Sv. Our results, under very strict assumptions, clearly demonstrate that the calculated radiation exposure to medical and non medical personnel is well below the maximum annual dose limit. The use of any additional radiation protection device as syringe shielding does not significantly lower radiation exposure.

Radiation exposure from patients treated with 165Dy-ferric hydroxide.

In radiation synovectomy about 10 GBq 165Dy-ferric hydroxide is injected into major joints. Measurements of the dose rates were performed at distances of 5 cm, 0.5 m, 1 m and 2 m from the surface of the treated joints (knees) until 200 min after the application in 16 patients in order to estimate the radiation exposure of persons in the neighbourhood of the patients. The highest doses were estimated for the fingers of the technologist (320 microSv) and for the physician (700 microSv). Special shields for the syringes were constructed for dose reduction. The whole-body doses were 103 microSv for the technologist and 40 microSv for the physician. After the discharge of the patient to a ward or home, other persons at 1 m distance from the patient might receive 88 microSv, which is less than 9% of the annual permissible dose. Our results clearly demonstrate that the calculated radiation exposure to personnel and family members is well below the maximum annual dose limit for non-professionally exposed persons.

Radiation awareness program for extracorporeal shockwave lithotripsy using Medstone lithotripters.

To determine the effectiveness of a radiation awareness program in reducing the radiation exposure to patients treated by a Medstone lithotripter, the exposure was calculated at the end of each extracorporeal shockwave (SWL) treatment using a table of measurements of the estimated entrance exposure rates 70 cm from the X-ray tube port. The results, related to stone size and patient weight, were distributed every month to each radiologic technologist, and a summary was sent regularly to the treating urologists. The doses before and after the introduction of the radiation awareness program were compared to determine the effectiveness of the program, and the chi-square test was used to determine statistical significance. The average calculated radiation exposure before and after introduction of the radiation awareness program was 16.39 rad and 8.26 rad, respectively, for patients with single renal stones; 17.31 rad and 9.02 rad, respectively, with single ureteral stones; 18.45 rad and 9.39 rad, respectively, with multiple renal stones; and 20.59 rad and 11.28 rad, respectively with multiple ureteral stones. These reductions in calculated radiation exposure were statistically significant only with multiple ureteral stones (P = 0.03). The only statistically significant differences in the stone-free rates, retreatment rates, and post-SWL secondary procedure rates before and after the introduction of the radiation awareness program were seen in the stone-free rates with single renal stones: 70% v 65%, respectively (P = 0.02); in the retreatment rates with single ureteral stones: 10% v 6%, respectively ( P < .01); and in the post-SWL secondary procedure rates with single renal stones: 4% v 2%, respectively (P = 0.01), and single ureteral stones: 7% v 4%, respectively (P = 0.05). The radiation awareness program resulted in a 51% reduction in the estimated radiation exposure to patients during SWL using Medstone lithotripters.

Fertility measures in women after extracorporeal shockwave lithotripsy of distal ureteral stones.

Long-term effects of extracorporeal shockwave lithotripsy (SWL) on female fertility remain a concern. Thirty-nine women of childbearing age who were treated for distal ureteral stones were surveyed. The mean age of these women was 33 years, and the average stone size was 6.9 mm. The mean calculated radiation exposure to the ovaries and the uterus was 7.53 and 10.9 mSv, respectively. Ten women (26%) attempted to become pregnant. No fertility problems were noted in these women, and 11 healthy babies were delivered. These preliminary findings provide further information regarding the safety of SWL in the treatment of distal ureteral stones in women of reproductive age.

A case for 77-bromine labelled radiopharmaceuticals

The use of radiobromine as a label for radiopharmaceuticals was demonstrated by the synthesis of 82Br-2,4-dibromoesterone, using the procedure of Slaunwhite and Neely. Structure determination of the brominated steroid was accomplished by the use of melting point data, paper chromatoraphy and mass spectra analysis. Tissue distribution studies in animals demonstrated rapid blood clearance and excretion in the bile. Calculated radiation exposure dose for 77Br-2,4-dibromoestrone is less than 131I-Rose Bengal. A significant difference in tissue distribution was found when the data for 82Br-2,4-dibromoesterone was compared to literature values for 82Br-7,8-dibromoesterone. Comparison with 131I-Rose Bengal and 99 m Tc-pyrodoxylideneglutamate suggest 77Br-2,4-dibromoestrone would be a tracer of potential value for liver and gallbladder function studies.

Variation in pulmonary retention of 131 I-macroaggregated albumin.

Counting over the right lung after the intravenous injection of 131I-macroaggregated albumin revealed a wide spread in retention half-times of the radiolabel (7 hours to 31 hours) even among patients having identical preparations. This needs further exploration as to its mechanism and its effect on the calculated radiation exposure of the lungs.