Evaluation of the Fetal-Maternal Radiation Doses in CT-Pelvimetry and Estimation of the Fetal Radiation Risks in 03 Radiology Departments in Douala-Cameroon

Background: CT in pregnant patients requires careful consideration of the radiation dose and corresponding radiation risks from ionizing radiation to the unborn child. The determination of foetal dose in diagnostic radiology is of interest as a basis for risk estimates from medical exposure of the pregnant patient. Objective: To evaluate the foetal-maternal radiation doses delivered during the CT-Pelvimetry procedure and to estimate the risk to the unborn child to develop a cancer in childhood and hereditary disease. Materials and Methods: We investigate the foetal-maternal radiation doses during CT-scan Pelvimetry in Douala (Cameroon). Data of 194 helical acquisition CT-Pelvimetry were collected between May 2017 and May 2019. An average DLP for the examination was established and the average effective dose was evaluated. The fetal dose was calculated and the FetDose V5 program was used for risk estimations. Results: The average dose length product (DLP) was 56.17 mGy·cm (range: 51.69 - 59.21 mGy·cm). The average effective dose received by women pregnant was 0.78 mSv. The mean individual fetal dose was 1.5 mGy (range: 0.76 - 1.87 mGy). The risk of Childhood Cancer calculated was: range 1 in 16,000 to 1 in 10,000 and 1 in 260,000 to 1 in 106,000 to the risk of Hereditary Disease, respectively. Conclusion: This study shows that the foetal-maternal doses delivered during CT-Pelvimetry examinations are very low and the risks of childhood cancers and hereditary diseases are derisory, the technology should be further investigated to ensure its full potential for optimal diagnostic accuracy.

Dosimetric Comparison of Craniospinal Axis Irradiation (CSI) Treatments Using Helical Tomotherapy, Smartarc^TM, and 3D Conventional Radiation Therapy

Purpose: Craniospinal axis irradiation (CSI) is a method of treating various central nervous system malignancies. The large target volume typically includes entire spinal cord and whole brain. Dosimetric comparison was performed between tomotherapy, volumetric modulated arc therapy (VMAT), and 3D conformal radiation therapy (3D-CRT) for CSI. Methods and Materials: Five (n = 5) CSI patients were planned using 3D-CRT, VMAT, and tomotherapy (normalized such that 95% of PTV received at least 23.4 Gy in 13 fractions). Plans were compared using PTV conformity number (CN) and homogeneity index (HI), normal tissue (NT) dose statistics, integral dose, and treatment time. Results: On average, tomotherapy plans showed higher CN (0.932 vs. 0.860 and 0.672 for SmartArc and 3D-CRT). In terms of HI, VMAT plans consistently showed better dose homogeneity (1.07 vs. 1.15 and 1.13 for tomotherapy and 3D-CRT). SmartArc delivered lower maximum dose for majority of NT, but higher mean dose. 3D-CRT plans delivered higher maximum dose but lower mean dose to NT. Conclusions: SmartArc treatments achieved better PTV homogeneity and reduced maximum dose to NT. Tomotherapy showed better target conformity, but 3D-CRT was shown to reduce mean dose to NT. Integral doses were similar between treatment modalities, but tomotherapy treatment times were much longer.

Diagnostic Reference Levels of Adults CT-Scan Imaging in Cameroon: A Pilot Study of Four Commonest CT-Protocols in Five Radiology Departments

CT-scan is the most irradiating tool in diagnostic radiology. For 5% - 10% of diagnostic X-ray procedures, it is responsible for 34% of irradiation according to UNSCEAR. Patients radiation protection must therefore be increased during CT-scan procedures. This requires the rigorous application of optimization principle which imposes to have “diagnostic reference levels”. Objective: The aim of this study was to determine the diagnostic reference levels (DRLs) of the four most frequent CT-scans examinations of adults in Cameroon. Material and Method: It was a cross-sectional pilot study carried out from April to September 2015 in five health facilities using CT-scan in Cameroon. The studied variables were: patients age and sex, type of CT-scan examination (cerebral, chest, abdomino-pelvic, lumbar spine), Used of IV contrast (IV﹣/ IV+), acquisition length, time of tube rotation, voltage (kV), mAs, pitch, thickness of slices, CTDIvol and DLP. For each type of examination, at least 30 patients were included per center, consecutively on the randomly predetermined days. The DRL for each type of examination was defined as the 75th percentile of its PDL and CTDIvol. Results: Of the 696 examinations, 41.2% were cerebral, 26.9% abdomino-pelvic, 17.7% lumbar spine and 14.2% chest. The mean age of patients was 52 ± 15 years [20 - 90 years], 58.9% were 50 years and older. The sex-ratio was 1.26 (55.9% males). The CT machines were 4, 8 and 16 multidetectors. The 75th percentile of DLP or DRLs [standard deviation] was: [1150 ± 278 mGy·cm], [770 ± 477 mGy·cm], [720 ± 170 mGy·cm] and [715 ± 187 mGy·cm] respectively for cerebral, lumbar spine, abdominopelvic and chest CT-scans. Taking in consideration the number of detectors, the 75th percentile of the Dose-Length product decreased with the increase number of detectors for cerebral examinations but was the highest with 16 MDCT for the abdominopelvic, lumbar spine and chest CT-scans. For the chest and lumbar spine examinations, there was a significant increase in patient-dose with the increase in the number of detectors. Conclusion: Our DRLs values lie between the norms of some European countries and those of some African countries. There is remarquable variation in dose for the commonest CT-scans examinations in Cameroon, requiring then an optimization process from these determined DRLs and establishment of national DRLs. Special attention to optimization should be paid when using 16 MDCT.

Resection of a locally advanced hilar tumor and the hepatic artery after stepwise hepatic arterial embolization: A case report

We herein report a case of a hilar tumor with extensive invasion to the proper hepatic artery, which was successfully treated with a radical resection in a 57-year-old female patient after a stepwise hepatic arterial embolization. She underwent right colectomy and partial hepatectomy for advanced colon cancer two years ago and radiofrequency ablation therapy for a liver metastasis one year ago, respectively. A recurrent tumor was noted around the proper hepatic artery with invasion to the left hepatic duct and right hepatic artery 7 mo previously. We planned a radical resection for the patient 5 mo after the absence of tumor progression was confirmed while he was undergoing chemotherapy. To avoid surgery-related liver failure, we tried to promote the formation of collateral hepatic arteries after stepwise arterial embolizationof the posterior and anterior hepatic arteries two weeks apart. Finally, the proper hepatic artery was occluded after formation of collateral flow from the inferior phrenic and superior mesenteric arteries was confirmed. One month later, a left hepatectomy with hepatic arterial resection was successfully performed without any major complications.

Inter-Observer Variability in the Detection and Interpretation of Chest X-Ray Anomalies in Adults in an Endemic Tuberculosis Area

Purpose: To assess the inter-observer agreement in reading adults chest radiographs (CXR) and determine the effectiveness of observers in radiographic diagnosis of pulmonary tuberculosis (PTB) in a tuberculosis endemic area. Methods: A quasi-observational study was conducted in the Pneumology Department of Yaounde Jamot Hospital (Cameroon) from January to March 2014. This included six observers (two chest physicians, two radiologists, two end-training residents in medical imaging) and 47 frontal CXRs (4 of diffuse interstitial lung disease, 6 normal, 7 of lung cancers, 7 of bacterial pneumonia, 23 of PTB). The sample size was calculated on the basis of an expected 0.47 Kappa with a spread of 0.13 (α = 5%, CI = 95%) for six observers and five diagnostic items. The analysis of concordance was focused on the detection of nodules, cavitary lesions, pleural effusion, adenomegaly and diagnosis of PTB and lung cancer. These intervals of kappa coefficient were considered: discordance (0.81). Results: The average score for the detection of caverns was the highest (58.3%) followed by that of the correct diagnosis of tuberculosis (49.3%). Pneumologists had the highest proportions of correct diagnosis of tuberculosis (69.6% and 73.9%) and better inter-observer agreement (k = 0.71) for PTB diagnosis. Observers were more in agreement for the detection of nodules (0.32 - 0.74), adenomegalies (0.43 - 0.69), and for the diagnosis of cancer (0.22 - 1) than for the diagnosis of tuberculosis (0.19 - 0.71). Disagreements were more frequent for the detection of pleural effusions (-0.08 - 0.73). Conclusion: The inter-observer agreement varies with the type of lesions and diagnosis. Pneumologists were most effective for the diagnosis of pulmonary tuberculosis. Observers were more in agreement for the detection of nodules and the diagnosis of cancer than for the diagnosis of pulmonary tuberculosis.

Reliability of Thyroid Imaging Reporting and Data System(TIRADS)Classification in Differentiating Benign from Malignant Thyroid Nodules

Background: Ultrasonography (US) is the best diagnostic tool in the initial assessment of thyroid nodule. Giving its appropriateness and accessibility, ultrasound-based thyroid imaging reporting and data systems (TIRADS) classifications have been developed with main goal to standardize reporting and facilitate communication between practitioners, and to indicate when fine-needle aspiration biopsy (FNAB) should be performed. Objective: To determine the reliability of Russ’ modified TIRADS classification in predicting thyroid malignancy. Materials and Methods: It was a cross sectional study carried out at Centre Hospitalier de Lagny, Marne La Vallée (France). Consecutive records of patients with focal thyroid nodules on ultrasound (US) for which US-guided FNAB was performed and pathology results were available, from January 2007 to August 2012, were selected for review. The risk of malignancy of each TIRADS category was determined and correlation with pathology assessed. Statistical performances of some US features were also assessed. The threshold for statistical significance was set at 0.05. Results: A total of 430 records of patients were eligible. Twenty-three out of 430 (5.3%) nodules were malignant. The risk of malignancy of the TIRADS categories were as follows: TIRADS2 0%, TIRADS3 2.2%, TIRADS4A 5.9%, TIRADS4B 57.9%, TIRADS5 100% (Gamma statistic = 0.85;Spearman correlation = 0.30, Pearson’s R = 0.37, p Conclusion: Russ’ modified TIRADS classification is reliable in predicting thyroid malignancy. More evidence is nevertheless necessary for widespread adoption and use.

Referring Physicians’ Knowledge on Justification of Medical Exposure in Diagnostic Imaging in a Sub-Saharan African Country, Cameroon

Background: Justification is the process of weighing the potential benefit of the exposure against potential detriment for that individual. Its role has been largely delegated to imaging professionals. Nevertheless, justification process involves referring physicians, radiographers and radiologists. Objective: To assess the knowledge of referring physicians regarding justification of irradiating examinations in medical imaging at the university-affiliated hospitals in Yaoundé Cameroon. Materials and Methods: A questionnaire (18 questions) based on the French guide for the proper use of medical imaging tests in relation to the justification of irradiating examinations, was self-administered to 151 referring physicians in Yaounde (Cameroon) between October 2012 and January 2013. The pre-tested questionnaire was completed in the presence of the investigator. A scoring system was then adopted with a total of 15 points from the level of knowledge on justification which could be classified as satisfactory or not. Results: Referring physicians were 75 (49.7%) GPs, 53 (35.1%) residents and 23 (15.2%) specialists. Knowledge on justification was unsatisfactory for 79.5% of referring physicians with no significant difference in terms of professional experience (p = 0.95) or specialty (p = 0.119). The concepts of “useful exam” and “justified exam” were not known by 113 (74.8%) and 95 (62.9%) practitioners. MRI was selected as irradiating by 62 (41.1%), SPECT and PET-scan as non-radiating examinations by 98 (64.9%) and 115 (76.1%) participants. The main reasons for repeating a giving radiology exam were: unsatisfactory interpretation, unknown of where it was performing and poor quality exam respectively for 23 (15.2%), 37 (24.5%) and 43 (28.5%) referring physicians. Justification was the responsibility of the referring physician alone for 57% of respondent. Only 11 clinicians knew the reference of “Justification-Optimization-Limitation” to radiation protection. Conclusion: The knowledge of physicians on radiating medical procedures and justification of requests for these procedures is inadequate. Training in radiation protection and the introduction of guidelines for the proper use of imaging tests could improve physicians’ justification of radiating examinations.

Kinetics of Iododeoxyuridine release from sodium alginate hydrogel in vitro

Objective To investigate the kinetics of Iododeoxyuridine(IUdR)release from sodium alginate hydrogel cross-linked with varying amounts of calcium chloride, and to optimize sustained release for further periadventitial I125-labeled IUdR delivery to suppress intimal hyperplasia following angioplasty in vivo. Methods Four hydrogels,composed of 0.16 mEq sodium alginate and 200 g IUdR, were cross-linked with calcium chloride to yield ion equivalence (IE) ratios (Calcium: alginate) of 3:1, 4:1, 5:1, or 6:1. 2 ml of normal saline was placed on top of each hydrogel and allowed to remain in contact at 37℃ for up to 30 days. At set time intervals, the concentration and amount of IUdR in the eluate were assayed by high performance liquid chromatography using UV detection and Water symmetry C18 column. The data for accumulated release rate and concentration in the eluate were calculated based on the calibration curve of peak area versus IUdR concentration. The hydrogel morphologic degradations were also observed. Results The hydrogels entrapped 92.9%, 98.6%, 98.4% and 98.6% of the IUdR with 3:1, 4:1, 5:1 and 6:1 IE ratios, respectively. IUdR concentration in eluates from 3:1 IE ratio hydrogel decreased faster than that from other hydrogels over time (P < 0.01). The 4:1, 5:1 and 6:1 IE ratio hydrogels produced more than 10 μm IUdR concentrations in eluates for the first 8 days, while the 3:1 IE ratio hydrogel for 4 days. IUdR release rates of the 4:1, 5:1 and 6:1 IE ratio hydrogels were very close, however they were lower than that of the 3:1 IE hydrogel in the first 48 hours (P < 0.05). At day 30, the 3:1 and 4:1 IE ratio hydrogels had 100% and 88% degradation, but no significant degradation was observed in the other hydrogels. Conclusion The sodium alginate hydrogel with 4:1 IE ratio exhibited an optimal IUdR sustained release and almost complete degradation in 30 days. (J Intervent Radiol, 2006, 15: 293-298)

Potential Association between Anterior Cruciate Ligament Tear and “Bi-Collateral” Ligamentous Rupture: A Retrospective Study

Background: Anterior cruciate ligament (ACL) tears are common complications of knee trauma. This entity can be reliably diagnosed by Magnetic Resonance Imaging. There is a lack of data on the epidemiology of ACL tears in Sub-Saharan Africa. The aim of this study is to describe the radiological aspects of post traumatic ACL tears in a black African setting (Yaounde Teaching Hospital). Methods: ninety six (96) MR studies of the knee were retrospectively reviewed. They were realized on a low field device (0.2T) from July 2012 to December 2013. All the examinations were indicated for knee trauma. Ligamentous, meniscal, bony and joint lesions were sought on coronal and sagittal sections. Results: the sample consists of 70% (68/96) of men. The mean age is 35.36 ± 11.86 years. The prevalence of ACL tears is 45.8% (44/96) of which 36 (81.81%, 36/44) are total tears. 23 (24%) have associated meniscal lesion and 8 (8.3%) have a simultaneous damage of the collateral ligaments. The most frequently injured part of the meniscus is its posterior horn (12/23 cases). Meniscal and “bi-collateral” ligament injuries are independently associated to ACL tears. Conclusion: The prevalence of ACL tears at the Yaounde Teaching Hospital is 45.8%. It is independently associated to meniscal tears and concomitant injury of the tibial and fibular collateral ligaments.

Monte Carlo模拟法评估多层螺旋CT扫描时胎儿所受剂量与孕妇体型及孕龄关系

目的利用Monte Carlo模拟法对不同胎龄及不同母体体型的孕妇进行腹部或盆腔检查时胎儿所接受的辐射剂量。

对局限性前列腺癌患者采用直肠内球囊中度低分割调强放射治疗的长期结局

背景与目的放射治疗的技术进步使兼顾剂量递增和提升膀胱和直肠保留成为可能。然而,对于局限性前列腺癌的最佳辐射剂量分割方案尚不清楚。实验室和临床证据表明,低分割可提高放疗的治疗率。在此报道我们医院采用中度低分割调强放疗(intensity?modulated radiotherapy,IMRT)和直肠内球囊对局限性前列腺癌患者的治疗结局,重点关注患者的长期生化控制和治疗相关不良事件。方法从1997年1月到2004年4月,596例c T1–T3前列腺癌患者使用带直肠内球囊的中度低分割方案(76.70 Gy,2.19 Gy/次)进行IMRT。根据D'Amico分类低风险、中风险或高风险患者分别226(37.9%)例、264(44.3%)例和106(17.8%)例。大多数中、高风险患者接受雄激素剥夺治疗。使用2005年Phoenix标准评估无生化复发生存(biochemical relapse?freeSurvival,bRFS),并使用Kaplan?Meier法进行估算。结果中位随访时间为62个月。总的5年bRFS和10年bRFS率分别为92.7%和87.7%。低风险、中风险和高风险患者的5年bRFS率分别为96.9%、93.3%和82.0%,10年bRFS率分别为91.4%、89.3%和76.2%。前列腺特异性抗原、Gleason评分和T分期是bRFS的重要预测因子(均P<0.01)。重度(≥3级)不良事件的5年发生率非常低:胃肠道不良事件和泌尿生殖系统不良事件的发生率分别为1.2%和1.1%。结论中度低分割IMRT后的长期结局令人鼓舞。中度低分割是治疗局限性前列腺癌的安全、有效的替代方案。

Long-term outcome of a moderately hypofractionated, intensity-modulated radiotherapy approach using an endorectal balloon for patients with localized prostate cancer

Background:Technical advances in radiotherapy delivery have simultaneously enabled dose escalation and enhanced bladder and rectal sparing.However,the optimal radiation fractionation regimen for localized prostate cancer is unclear.Laboratory and clinical evidence suggest that hypofractionation may improve the therapeutic ratio of radiotherapy.We report our institutional outcomes using moderately hypofractionated,intensity-modulated radio-therapy(IMRT),and an endorectal balloon,with emphasis on long-term biochemical control and treatment-related adverse events in patients with localized prostate cancer.Methods:Between January 1997 and April 2004,596 patients with cT1-T3 prostate cancer underwent IMRT using a moderate hypofractionation regimen(76.70 Gy at 2.19 Gy/fraction)with an endorectal balloon.Using D’Amico clas-sification,226(37.9%),264(44.3%),and 106(17.8%)patients had low-,intermediate-,or high-risk disease,respectively.The majority of intermediate-and high-risk patients received androgen deprivation therapy.Biochemical relapse-free survival(bRFS)was evaluated using 2005 Phoenix criteria and estimated using the Kaplan-Meier method.Results:The median follow-up was 62 months.Overall 5-and 10-year bRFS rates were 92.7%and 87.7%.For low-,intermediate-,and high-risk patients,the 5-year bRFS rates were 96.9%,93.3%,and 82.0%,respectively;the 10-year bRFS rates were 91.4%,89.3%,and 76.2%,respectively.Prostate-specific antigen,Gleason score,and T stage were significant predictors of bRFS(all P<0.01).The 5-year rates of severe(≥Grade 3)adverse events were very low:1.2%for gastrointestinal events and 1.1%for genitourinary events.Conclusions:Long-term outcomes after moderately hypofractionated IMRT are encouraging.Moderate hypofrac-tionation represents a safe,efficacious,alternative regimen in the treatment of localized prostate cancer.