Analysis of the eye lens dose and annual effective dose to some interventional radiation workers in Xinxiang city / 中华放射医学与防护杂志

Objective:To analyze the eye lens dose and annual effective dose to interventional radiation workers in some hospitals of Xinxiang city from 2020 to 2022, and to ascertain the dose to interventional radiation workers.Methods:By using TLDs, the eye lens dose Hp(3) and annual effective dose Hp(10) were monitored for three consecutive years in six hospitals in Xinxiang city. The lens doses and annual effective doses to intervention radiation workers in different years in different-level hospitals and departments were analyzed. Results:From 2020 to 2022, a total of 117 people were monitored. The left eye lens dose range was 0.12-164.24 mSv, and the right eye lens dose range was 0.07-51.64 mSv. The average annual dose was 8.56 mSv for left eye lens and 4.49 mSv for right eye lens The average annual dose distribution in the MDL-5 mSv range for the left and right eye lens was 60.68% and 73.50%, respectively. 9.41% (11 people) of the left eye lens doses exceeded 20 mSv. The annual effective doses range was 0.11-31.27 mSv, with average annual dose of 2.56 mSv. The proportion of average annual effective doses mainly distributed in the range of MDL to 1.25 mSv was 52.14%, with 2.56% annual effective dose exceeding 20 mSv. There was no significant difference in left and right eye lens dose and annual effective dose between the tertiary hospitals and the secondary hospitals in three years ( P>0.05). Compared with different departments, the cumulative per capita dose in three years was statistically significant (left eye H=11.42, right eye H=13.72, annual effective dose H=25.94, P<0.05). The lens dose and annual effective dose in neurology department were lower than those in cardiology department and comprehensive intervention department ( Zcardiology department=-3.33, -3.78, -4.83, P<0.05; Zcomprehensive intervention department=-2.71, -2.63, -4.39, P<0.05). Conclusions:Most of the annual equivalent dose and annual effective dose to eye lens of the interventional radiation workers in Xinxiang city meet the national limits, but some of them have higher doses and exceed the national limits. It is suggested that the routine and continuous monitoring of eye lens doses to interventional radiologists should be strengthened while routine monitoring of annual effective dose, and attention should be paid to the eye lens and annual effective dose to interventional radiologists in secondary hospitals to improve the awareness of protection.

Discussion of Hp(3) calibration with two thermoluminescent dosimeters in the same standard X-ray RQR radiation field / 中国辐射卫生

Objective To compare Hp(3) calibration with a homemade (A) thermoluminescent dosimeter (TLD) and an imported (B) TLD in a standard X-ray RQR radiation field, to explore the different responses of A and B, and to provide foundation for the calibration of Hp(3). Methods A column mode was selected. Hp(3) calibration was performed using A and B in a standard X-ray RQR radiation field in the Secondary Standard Dosimetry Laboratory, National Institute for Radiological Protection, China Center for Disease Control and Prevention. Angle response, energy response, and linear response were calibrated with RQR4 (60 kV), RQR7 (90 kV), and RQR9 (120 kV), respectively. Results In terms of angle response, the calibration results of A were relatively high, while the calibration results of B were relatively low. In terms of energy response, the calibration results showed a similar pattern to angle response. In terms of linear response, the calibration results of both A and B were satisfactory. Conclusion Both A and B can be used for normal calibration of Hp(3) in a standard X-ray RQR radiation field. However, in actual monitoring, attention should be paid to the energy and angle response values of TLDs.

Monte Carlo simulation and analysis of eye lens dose of the first operator in interventional therapy / 中国辐射卫生

Objective To establish a model for estimating the eye lens dose of the first operator in interventional therapy based on the Monte Carlo simulation, and to provide a scientific basis for the rapid and accurate evaluation of the eye lens dose for radiation workers in interventional therapy. Methods Based on the MIRD phantom and eye model for adult Chinese males, the MCNPX program was used to establish the physical model to calculate the spatial distribution of radiation field and eye lens dose for the first operator. A GR200 Type A LiF (Mg, Cu, P) thermoluminescence dosimeter was used for experimental measurement to verify the simulation results. Results Monte Carlo simulation and experimental measurements showed that the spatial distribution of radiation field was symmetrical. Compared with the measured doses, the errors of the simulated eye lens dose of the first operator were between −8.3% and 7.3%. The dose of the left eye lens was higher than that of the right eye. Conclusion The Monte Carlo model constructed in this study initially realizes the simulation of eye lens dose of the first operator in interventional therapy. In the future, the model will be further optimized based on irradiation parameters such as exposure time, tube voltage, tube current, and projection direction used in clinic practice, so as to more accurately evaluate the eye lens dose of interventional therapy staff.

The investigation and analysis of eye lens dose to interventional radiology workers in China from 2019 to 2021 / 中华放射医学与防护杂志

Objective:To investigate and analyze the eye lens dose to interventional radiology workers in China from 2019 to 2021.Methods:The monitoring data on eye lens dose to interventional radiology workers from 31 province-level units during 2019-2021 were collected through the National Radiological Health Information Platform. The eye lens dose evaluation indicator was Hp(3), with each monitoring period of no more than 3 months. Kusall-Wallis H test was used for the comparison of multiple groups and pairwise. Results:A total of 6 643 interventional radiology workers were investigated from 2019 to 2021. The average annual eye lens dose was 1.03 mSv, with the median of 0.17 mSv and the maximum of 94.88 mSv. The annual eye lens dose to 59 workers exceeded 20 mSv. It was also found that the annual eye lens dose to the doctors in 2019 and 2020 was slightly higher than that to nurses (rank mean difference=118.29, 129.71, P<0.01), and the lens dose to interventional radiology workers who performed cardiac interventions in 2019 was higher than that to workers who performed peripheral vascular interventions (rank mean difference=46.52, P<0.05). Conclusions:The lens dose to interventional radiology workers is lower than the limits given in Chinese national standard currently in effect, but exceed the latest internationally recommended limit for a few ones. In order to protect the occupational health of interventional radiology workers, the monitoring of lens dose should be strengthened.

A study and analysis of eye lens dose levels of medical staff during interventional cardiology procedures / 中国辐射卫生

Objective To analyze the eye lens equivalent dose levels of doctors during interventional cardiology procedures and identify related influential factors. Methods Twenty interventional specialists were selected from a cardiovascular specialty hospital. The cumulative equivalent doses to their eye lens during operations were monitored, and equipment-related parameters (fluoroscopy time, dose area product value [DAP], and entrance skin dose[ESD]), operation types, and operators’ positions were recorded. Results The annual equivalent doses to the eye lens of seven doctors exceeded 20 mSv. There was a linear correlation between the weekly number of operations and the equivalent dose to the eye lens (R2 = 0.457, P = 0.001). The mean eye lens equivalent dose per operation was 17.1 μSv, showing linear correlations with fluoroscopy time, DAP values, and ESD values (R2 = 0.427, 0.206, and 0.237, respectively, P < 0.05). The fluoroscopy time, DAP value, ESD value, and eye lens equivalent dose during percutaneous coronary intervention (PCI) were significantly higher than those during coronary angiography (t = −3.226, −3.108, −3.061, and −2.667, respectively, P < 0.03). Conclusion The annual equivalent doses to the eye lens are relatively high in interventional radiologists, some of whom may have values higher than the latest dose limit (20 mSv) suggested by the International Commission on Radiological Protection. Attention should be paid to operators performing PCI, and the workload optimization is necessary in practical operations to avoid unnecessary fluoroscopy time and reduce the eye lens doses of the operators.

Evaluation of selected photon shield and organ-based tube current modulation for organ dose reduction and image quality in head CT for infants: a phantom study / 中华放射医学与防护杂志

Objective:To compare the dose and image quality of selected photon shield (SPS) technique, organ-based tube current modulation (OBTCM) technique and the combination of these two techniques for reducing the organ dose in head CT examination for infants.Methods:Two anthropomorphic head phantoms (CIRS 1-yr-old and 5-yr-old) were scanned by using Reference mode, Reference + OBTCM mode, SPS mode and SPS + OBTCM mode, respectively. Radiation doses to the lens of the eye, the anterior of the brain, the posterior of the brain, noise level and CNR of orbit and brain in different phantoms were measured and compared by using different scanning modes.Results:Compared with Reference mode, the doses to the lens of the eye in 1-yr-old and 5-yr-old phantom decreased by (21.89 ± 0.01)% and (28.33 ± 0.34)%, respectively. In SPS mode, the reduction in doses to the lens of the eye in 1-yr-old and 5-yr-old phantom were (71.38 ± 1.30)% and (53.72 ± 2.42)%, respectively. In SPS + OBTCM mode, the reduction was (71.12 ± 2.54)% and (55.73 ± 1.90)%, respectively. There was significant difference in the noise level of orbit and brain in different phantoms under various scanning modes ( F=5.67-85.47, P< 0.05). The noise level in OBTCM mode compared with reference mode increased slightly (<1.45 HU) in various phantoms. SPS and SPS + OBTCM mode resulted in a small noise increase (<2.58 HU). There was no significant difference in CNR of different phantoms under various scanning modes ( P>0.05). Conclusions:SPS and SPS + OBTCM mode can significantly reduce the radiation dose of lens and the whole image plane in the head CT scan for infants, with maintaining the image quality.

Effects of organ dose modulation technique on image quality and radiation dose in sinus CT scanning / 中华放射医学与防护杂志

Objective:To investigate the effects of organ dose modulation (ODM) on image quality and radiation dose to lens during sinus CT scanning.Methods:The GE Revolution EVO CT was used to scan the anthropomorphic head with ODM turned off as the control group and ODM turned on as the observation group. With different parameter combinations of tube voltage (140, 120, 100 kV), noise index (N17, N18), pitch (0.531, 0.969 at 20 cm collimation width, 0.516, 0.984 at 40 mm collination width), 24 series of images were acquired respectively. The tube current (mA) valuesat the anterior (A), left (L), posterior (P) and right (R) positions, volume CT dose index (CTDI vol) and dose length product (DLP) were recorded. Average CT values (AV), standard deviation (SD), signal-to-noise ratio (SNR), contrast to noise ratio (CNR) and image quality factor (FOM) of ROI were calculated. Double blind method was used to evaluate the edge sharpness, soft tissue level, noise and artifact on a subjective scale of 3 points. Results:For the combinations of different scanning parameters, the radiation dose of the observation group was lower than that of the control group. The tube current attheposition A for the observation group was lower than that of the control group, and the difference was statistically significant ( t=2.28, P<0.05). The differences oftube currentsatposotions of L, P and R, CTDI vol and DLP values in twogroupswere not statistically significant ( P>0.05). There were no significant differences in SD, SNR, CNR and FOM between the two groups of images ( P>0.05). There were no significant differences in the subjective scores of edge sharpness, soft tissue gradation, noise and artifacts between the two groups ( P>0.05). Conclusions:ODM technique can effectively reduce the radiation dose of eye lens without decompromising the image quality, which could meet the requirements of diagnosis, and accord with the principle of radiological protection optimization.

Harm of high LET radiation to the lens of the human eye / 中国辐射卫生

The biological effects of ionising radiation vary according to its linear energy transfer (LET) density, with higher LET radiation having stronger biological effects than lower LET radiation at the same absorbed dose. Though we have done more research in the area of radiation effects on the ocular lens, we know little about the effects of high LET on the ocular lens. This article briefly describes the historical changes in the dose limits of the human ocular lens, investigates the epidemiology of high LET radiation eye lens, summarizes various biological experiments of high LET particles, and briefly analyzes the reasons for the high prevalence of cataracts in the plateau. It also discusses the factors that need to be considered in the future research on high LET, aiming to provide valuable information for the future research of high LET eye lens in China.

Research of TLD calibrated in different standard X-ray RQR radiation field in terms of eye lens dose Hp (3) / 中华放射医学与防护杂志

Objective To compare the calibration result of standard X-ray RQR radiation field between SSDL (NIRP) and CEA LIST LNHB (France),and to explore the feasibility of calibrating Hp (3) in standard X-ray RQR radiation field of SSDL (NIRP).Methods Using a column model with a diameter and high of 20 cm,TLD was calibrated in SSDL (NIRP) and CEA LIST LNHB (France) to measure the personal dose equivalent eye lens dose Hp (3),X-ray RQR radiation field included RQR4 (60 kV),RQR7 (90 kV),RQR9 (120 kV),with energy response,angle response and linear response.Results In terms of energy response,the calibration results of TLD in both SSDL (NIRP) and CEA LIST LNHB (France) were in good agreement.The difference between exposure value and response value was less than 10％.In terms of angle response,the calibration result of TLD in CEA LIST LNHB (France) was better in SSDL (NIRP).The difference between exposure value and response value in CEA LIST LNHB (France) was less than 6％,while the difference between exposure value and response value in SSDI (NIRP) was more than 10％ at angle of 20°.In terms of linear response,both calibration result of SSDL (NIRP) and CEA LIST LNHB (France) were in good agreement.Conclusions The standard X-ray RQR field in SSDL (NIRP) can be used for the calibration of Hp (3).

Estimation of Effective Radiation Dose to the Eye Lens in Dental Cone Beam Computed Tomography

@#Introduction: Recent advancement in technology, has significantly improved the clinical application of Cone Beam Computed Tomography in the field of dentistry. The main objective of this study is to estimate the effective dose to the eye lens in Cone Bean Computed Tomography. Method: The effective dose to the lens of the eye was estimated using Dose Area Product (DAP) values from i-CAT 17-19 Platinum CBCT scanner during the CBCT examination of either the maxilla or mandible, with an exposure parameters of 120kVp and mAs 37.07. Results: The estimated effective dose for lens of the eye is 8.0±2.49mSv for voxel size 0.2 whereas 6.21±1.55mSv for voxel size 0.25 for CBCT of Mandible and 5.74±1.73mSv for voxel size 0.2 whereas 5.28±1.35mSv for voxel size 0.25 for CBCT of Maxilla. Conclusion: The effective dose to the lens of eyes for a standard protocols 0.2voxel with 26.9 sec and 0.25 voxel with 26.9 sec in CBCT for maxilla and mandible respectively are within the threshold limit of 2.0Gy. Therefore for further reduction of the effective dose to the lens of the eyes we recommend for developing a protocol with lower radiation dose and also implement the application of using an effective protective measures such as bismuth eye shield.

Research of TLD calibrated in different standard X-ray RQR radiation field in terms of eye lens dose Hp(3) / 中华放射医学与防护杂志

Objective@#To compare the calibration result of standard X-ray RQR radiation field between SSDL (NIRP) and CEA LIST LNHB(France), and to explore the feasibility of calibrating Hp(3) in standard X-ray RQR radiation field of SSDL(NIRP).@*Methods@#Using a column model with a diameter and high of 20 cm, TLD was calibrated in SSDL (NIRP) and CEA LIST LNHB (France) to measure the personal dose equivalent eye lens dose Hp(3), X-ray RQR radiation field included RQR4(60 kV), RQR7(90 kV), RQR9(120 kV), with energy response, angle response and linear response.@*Results@#In terms of energy response, the calibration results of TLD in both SSDL (NIRP) and CEA LIST LNHB (France) were in good agreement. The difference between exposure value and response value was less than 10%. In terms of angle response, the calibration result of TLD in CEA LIST LNHB (France) was better in SSDL(NIRP). The difference between exposure value and response value in CEA LIST LNHB (France) was less than 6%, while the difference between exposure value and response value in SSDL(NIRP) was more than 10% at angle of 20°. In terms of linear response, both calibration result of SSDL (NIRP) and CEA LIST LNHB (France) were in good agreement.@*Conclusions@#The standard X-ray RQR field in SSDL (NIRP) can be used for the calibration of Hp(3).

Study on estimation methods of absorbed dose to eye lens of infants from CT head and neck scanning based on one-year old anthropomorphic phantom / 中华放射医学与防护杂志

Objective To study the methods to estimate absorbed dose to eye lens of infants from CT scanning using different protocols and try to find a practical quick way for estimating absorbed dose to eye lens.Methods By scanning one-year old anthropomorphic phantom using 7 kinds of different protocols,all TLDs were measured for final estimation of absorbed dose to eye lens using two different dose conversion methods.Meanwhile,linear regression equation was established between absorbed dose to eye lens and CTDI.Results Absorbed doses to eye lens of infants from children CT scanning using 7 kinds of different protocols were (9.96±0.69) mGy in head axis,(7.01±0.42) mGy in head helical,(12.60± 0.97) mGy in sinus,(12.97±0.42) mGy in inner ear,(0.63±0.03) mGy in neck soft tissue,(8.89± 0.44) mGy in cervical vertebra,and (0.34± 0.01) mGy in chest,respectively.There were statistically significant difference in doses among different groups (F =846.826,P ＜ 0.05).For different scanning locations,there was linear relation between absorbed dose to eye lens and CTDI(r=0.986-0.999,P＜ 0.05).Conclusions Absorbed dose to eye lens of infants from children CT scaning with single dose may not be above threshold dose.In addition,absorbed dose to eye lens can be estimated quickly by linear regression equation between absorbed dose to eye lens and CTDI.

Reproduction and growth in a Neotropical arboreal mouse: Oecomys rutilus (Sigmodontinae: Cricetidae) in French Guiana / Reprodução e crescimento de um rato arbóreo neotropical: Oecomys rutilus (Sigmodontinae: Cricetidae) na Guiana Francesa

Abstract: Postnatal growth and development of the small Neotropical mouse Oecomys rutilus (Sigmodontinae: Cricetidae) were investigated from birth to day 143, in the laboratory. Morphometric measurements at age of 3 days, of both sexes combined, revealed body weight to be 3.4 ± 0.3 g, mean tail length as 27.4 ± 1.1 mm, and mean hind foot length as 9.3 ± 0.7 mm. Body weight was found to increase steadily until at least 69 days, whereas the instantaneous growth rates of other measurements declined earlier: the daily growth of hind foot length declined to a minimum at age of 24 days, and the growth of tail and of ear declined by the age of 33 days. Average litter size for 12 captive births was 2.5, ranging from 2 to 3. The preserved eye crystalline lens was weighted in 23 captive-born animals of known age, allowing a rough estimate of the age of reproduction in wild-caught animals. Based on the inferred relation between eye-lens weight and age, the youngest reproductive (pregnant) wild-caught females had an estimated age of 90 and 95 days.

Resumo: O crescimento pós-natal e o desenvolvimento do pequeno roedor neotropical Oecomys rutilus (Sigmodontinae: Cricetidae) foram investigados desde o nascimento até o dia 143, em laboratório. Mensurações morfométricas na idade de 3 dias, de ambos os sexos combinados, revelaram a massa corporal de 3,4 ± 0,3 g, comprimento médio da cauda de 27,4 ± 1,1 mm, e comprimento médio do pé de 9,3 ± 0,7 mm. A massa do corpo aumentou rapidamente até o dia 69, enquanto as taxas de crescimento instantâneo de outras medidas diminuíram mais cedo: o crescimento diário do pé diminuiu para o mínimo na idade de 24 dias, e os crescimentos da cauda e da orelha diminuíram na idade de 33 dias. O tamanho de prole médio para 12 nascimentos em cativeiro foi de 2,5, variando de 2 a 3. As lentes preservadas do cristalino do olho foram pesadas em 23 animais nascidos em cativeiro de idades conhecidas, permitindo fazer uma estimativa da idade de reprodução em animais capturados na natureza. Baseado na relação inferida entre peso da lente do cristalino e idade, as mais jovens fêmeas (prenhes) capturadas na natureza tiveram uma estimativa de 90 a 95 dias de idade.

Analysis on illuminated dose level of operators' eyes in imaging quality control test of positron emission tomography / 中华放射医学与防护杂志

Objective To investigate the eye lens dose to the operators who tended to test the quality control of positron emission tomography (PET).Methods Before encapsulation and in preparation of point source,line source 1 and line source 2,the two operators were worn with lens thermoluminescence dosimeter each at the left of the left eye,the front of the left eye,between the right eye and the left eye,the left of the right eye,and the front of the right eye.Measurement and analysis were made of the radiation doses to eye lens received by the operators in order to calculate their maximum annual doses.Results The maximum lens dose was 2 439.80 μSv for the test of 5 PETs.There appears to be the same trend in the eye lens doses for the first and second operators.(x2 =15.629-16.155,P ＜ 0.05).The first operator have received higher eye lens dose higher than the second(Z =2.611,P ＜ 0.05).Conclusions The dose to the eye lens for a single PET test is relatively low.

Establishment of standards of Hp(3) for the calibration of eye-lens dose equivalent dosimeters / 中国医学装备

Objective:To establish the X-ray standard was used to calibrate Hp(3) dosimeter in order to satisfy the requirement of eye-lens dose equivalents for the radiological occupational staff.Methods:The conventional values (Hp(3)) on the reference point of the narrow beams of X-ray fields were obtained by means of the product of air kerma (Kair) and the conversion coefficients (hp(3,ɑ)) recommended by ICRP116 recommendation. And these researches can be used by standard ionization chamber dosimeter. Finally, provided the conventional true value Hp(3) at calibrate point.Results:The standards and calibration program of calibrations eye-lens dose equivalent dosimeter were established under the X-ray radiation field. The detection error between slab phantom recommended by ISO and head phantom recommended by the 116th publication of ICRP was lower when the TLD was used to detect result.Conclusions:The standards for calibration Hp(3) dosimeters can satisfy the requirement of calibration for radiological occupational staff. It also provides theoretical foundation for detection data that assessed Hp(3) dosimeters and then improves trace ability and reliability of detection data of Hp(3) in national radiation supervision and inspection network.

Discussion on selection and use of eye lens protective equipment for interventional staff / 中华放射医学与防护杂志

The decreased occupational dose limit for eye lens has lead to an extensive focus on the eye lens dose monitoring and protection for occupational staff in interventional procedures.Based on the literature investigation of existing measurement and calculation results,the efficiency and influence factors of eye lens protective equipments for interventional staff are analyzed,and the suggestions for selection and use of them are provided.The main contribution to the eye lens dose to interventional staff is unshielded radiation which reaches the eyes directly.The key factors to inflence the efficiency of eye lens protective equipment is the geometric conditions such as structure,beam projection,position arrangement and operator postures,instead of lead equivalent thickness.Equipment of 0.5 mm lead equivalent thickness is enough to protect the eye lens of interventional staff.The combination of lead glasses and lead barrier can provide better protection in clinical practice.

Effect of auxiliary radiological protective devices on reducing dose to the eye lens of interventional staff / 中华放射医学与防护杂志

Objective To establish a method for reducing the dose to the eye lens of interventional staff,and provide the data basis for improving radiological protection measures.Methods One piece of interventional equipment coupled with conventional auxiliary protective devices and two types of common neural interventional procedures were selected to monitor 46 and 35 procedures before and after the device modification.The doses to the eye lens of staff were measured with direct-reading dosimeters for analysis of dose trends.Results After modification of the devices,the average dose to the left eye lens decreased from (9.71 ±10.86) to (3.23 ±5.59) μSv for the first operator,from (9.51 ± 12.34) to (0.68 ± 0.78) μSv for the second in cerebral angiography;whereas the dose decreased from (14.83 ± 19.13) to (4.17±4.59) for the first operator and from (14.12±21.76) to (1.23 ±1.57)μSv for the second in embolization procedure,respectively.The left eye lens doses measured before and after the modification showed significant difference (U =-2.760,-2.467,-1.967,-2.655,P ＜0.05).Conclusions The modification of the auxiliary radiological protective devices may effectively reduce the dose to the eye lens dose.This method was shown to be feasible for the improvement of radiological protection of interventional staff.

Study of real-time measurements of occupational staff's eye lens doses by direct-reading dosimeters in interventional procedures / 中华放射医学与防护杂志

Objective To establish the methods for measuring the dose to occupational staff's eye lens in interventional procedures with direct-reading dosimeters,and to realize the real-time monitoring of eye lens dose and warning for high dose rate,thus providing the scientific basis of the staff radiological protection in interventional procedures.Methods Direct-reading dosimeters were calibrated with personal dose equivalent HP (3).The eye lens doses for occupational staff in different kinds of interventional procedures were measured by the devices with both single-and double X-ray tubes.The data obtained fromthe direct-reading dosimeters was compared to those obtained from TLDs.Results Direct-reading dosimeters showed good linear fitting with the calibration of HP (3),and the coefficients of variation were lower than 5％.The average eye lens HP (3) for the main operator in coronary arteriography and stent implantation in brain obtained by direct-reading dosimeters were 12.0 and 24.5 μSv,respectively,whereas those obtained by TLDs were 11.9 and 22.7 μSv,respectively.The direct-reading dosimeters gave similar t~nds as TLDs do so.The direct-reading dosimeters were able to provide eye lens HP (3) in each individual interventional procedure,and to monitor the real-time dose rate as well.Conclusions The calibration of HP (3) and the data gained by direct-reading dosimeters are reliable.Therefore,the methods for real-time measurement of eye lens dose for occupational staff in interventional procedures are successfully established.

Investigation on effect of dual-source CT scanning patterns on radiation dose and image quality of head and neck / 中华放射医学与防护杂志

Objective To study the impact on the radiation dose,organ doses of eye lens and thyroid and image quality with different scanning modes in head and neck CT scan.Methods The simulation phantom of head and neck was scanned by using fixed scanning condition (120 kV and 200 mAs),as well as the combinations of automatic tube current modulation (CARE Dose 4D),automatic tube voltage modulation technique (CARE kV) and partial angle scanning mode (X-CARE) respectively.Six kinds of scanning modes were adopted,including 120 kV +200 mAs,120 kV + 200 mAs + X-CARE,CARE Dose 4D + 120 kV,CARE Dose 4D + 120 kV + X-CARE,CARE Dose 4D + CARE kV,CARE Dose 4D + CARE kV + X-CARE.Two thermolumineseece dosimeters (TLDs) were exposed at the skin surface positions of eye lens and thyroid,and the values measured with two TLDs were averaged.The CT dose index volume (CTDIvol) and dose length product (DLP) for every scan were recorded,and the contrast to noise ratio (CNR) in eye lens section and thyroid section were measured.Results The crgan doses of lens and thyroid were 19.8 and 26 mGy at 120 kV and 200 mAs,as well as 13.3 and 22.2 mGv at X-CARE mode.Compared with the manual selection of 120 kV,the combination of CARE kV and CARE Dose 4D made the values of CTDIvol drop from 13.1 to 10.1 mGy,the doses of eye lens and thyroid from 16.6 and 20.8 mGy to 23.7 and 19.9 mGy respectively,while the image quality reducedsignificantly.Compared with CARE Dose 4D + 120 kV,the organ doses of eye lens and thyroid were reduced from 20.8 and 23.7 mGy to 9.6 and 15.1 mGy for with additional X-CARE,while CTDIvol dropped from 13.1 to 9.3 mGy.When the combination of CARE Dose 4D + CARE kV + X-CARE was used,CTDIvol and organ doses were reduced to a minimum,when the CNRs of head and neck were also minimized.Conclusions The scanning mode CARE Dose 4D + 120 kV + X-CARE for head and CARE Dose 4D + CARE kV for neck can effectively reduce the radiation dose while keeping good image quality.When requirements for image quality are not high,CARE Dose 4D + CARE kV + X-CARE mode can be selected to reduce the radiation dose significantly.

The measurements of eye lens dose for occupational staff in interventional procedures / 中华放射医学与防护杂志

Objective To establish methods of measuring the eye lens dose to interventional staff,to obtain relevant dose data and to provide a scientific basis for reducing eye lens dose.Methods Two kinds of dosimeters,thermoluminescent dosimeter (TLD) and optically stimulated luminescence dosimeter (OSLD),were selected to measure the personal dose equivalent HP (3) to eye lens of occupational staff in several kinds of interventional procedures,including cardiovascular interventional procedures,cerebrovascular interventional procedures etc.Five types of Digital Subtraction Angiography (DSA) equipment were chosen in the study,including single tube equipment and double tube equipment.Results The eye lens dose HP (3) to interventional staff varied significantly with different interventional procedures.The lowest dose is shown in the coronary angiography procedure,while the highest dose shown in the cerebral stenting procedure.For the same type of interventional procedure,the eye lens dose to the primary interventionist was the highest.For same interventionist,the dose to the left eye was obviously higher than that to the right eye.In addition,the measured results of OSLD were apparently higher than that of TLD.Conclusions Both TLD and OSLD could be used to measure eye lens dose,and the ways of calibrating TLD to evaluate personal dose equivalent HP (3) were feasible.The reason of significant difference between the measured results of TLD and OSLD needs further research.