Provides an overview of radiation and CT use in pregnancy including indications and clinical scenarios. Presentation material taken from journals with overall theme based on lecture by Elliot K. Fishman, MD.
Guidelines for Diagnostic Imaging During PregnancySun Yai-Cheng
Guidelines for Diagnostic Imaging During Pregnancy
American College of Obstetricians and Gynecologists.
ACOG Committee Opinion No. 299.
Obstet Gynecol 2004;104:647–51.
Presentation contains info on Radiation Protection in Pregnancy - radiodiagnosis, MRI, nuclear medicine and radiotherapy. Including notes on foetal dose, shielding techniques in radiotherapy and precaution for pregnant radiographers/medical physicists.
Guidelines for Diagnostic Imaging During PregnancySun Yai-Cheng
Guidelines for Diagnostic Imaging During Pregnancy
American College of Obstetricians and Gynecologists.
ACOG Committee Opinion No. 299.
Obstet Gynecol 2004;104:647–51.
Presentation contains info on Radiation Protection in Pregnancy - radiodiagnosis, MRI, nuclear medicine and radiotherapy. Including notes on foetal dose, shielding techniques in radiotherapy and precaution for pregnant radiographers/medical physicists.
EBCTCG METAANALYSIS
INDICATION OF POST OP RADIOTHERAPY
Immobilization devices
Conventional planning
Alignment of the Tangential Beam with the Chest Wall Contour
Doses To Heart & Lung By Tangential Fields
EBCTCG METAANALYSIS
INDICATION OF POST OP RADIOTHERAPY
Immobilization devices
Conventional planning
Alignment of the Tangential Beam with the Chest Wall Contour
Doses To Heart & Lung By Tangential Fields
This presentation is almost a complete Pictoral view of Radiograph chest.
This presentation will help radiologist in daily reporting.
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This will also help all in preparaing TOACS examination.
Radiology ----Classical Signs in GIT Dr. Muhammad Bin Zulfiqar.
It is very difficult to learn much in the sea of radiology.
This presentation is the way to memorize classical signs in radiology.
Discusses cancer risk from low-dose radiation from medical imaging and how this applies to young or pregnant patients.
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Should the alara concept and the image gently campaign be terminated?Mohan Doss
Abstract: Concerns have been raised about the cancer risk from pediatric CT scans based on the linear no-threshold (LNT) model assumption for radiation-induced cancers, and the assumed increased radiosensitivity of children. The pediatric radiology community has responded by initiating the Image Gently campaign and recommendations to keep imaging radiation doses as low as reasonably achievable (ALARA). One of the main evidences quoted for the low-dose radiation cancer concerns are the atomic bomb survivor data. However, with the recent update, these data are not compatible with the LNT model but are more consistent with the concept that low levels of radiation reduce cancers, a phenomenon known as radiation hormesis. In addition, more evidences have validated radiation hormesis hypothesis and major flaws have been identified in the data claimed to support the LNT model. Thus, dose reduction due to the ALARA principle and Image Gently campaigns would not benefit pediatric patients by reducing cancer risk. The false perception that CT scans cause cancer has led to parents refusing indicated scans for children and physicians not ordering the needed scans, potentially jeopardizing patient health. Also, misguided dose reduction efforts have resulted in nondiagnostic images being performed, again potentially harming pediatric patients. Since there are no benefits from the low-dose radiation dose concerns and dose reduction efforts but only potential harm to pediatric patients, the radiological community should firmly disavow the ALARA concept and discontinue the Image Gently campaign.
Explain the non safe or harm aspects of CT scan on the patient,, particularly after multiple CT scans done for one patient. mentioned essentially the risk of cancer in later life, which reach 1/2000.
Also, mentioned the organs, age group, and gender which affected more by CT radiation
Finally , stressing on eliminating CT scan as possible
Radiation Risk from CT Scan and the possibility of getting cancer after receiving high dose of radiation.
Dr. Khalid Shokor Mahmood, neurosurgeon, Iraq
This lecture details the science of sepsis care in 2015 with compliments to the multiple online sources used, some of which are other lectures on SlideShare.
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Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
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2. Some Facts of Life Patients worry Sometimes their worries are real However, health care providers have to allay fears without prevarication when such fears are not grounded in evidence 2
3. Today’s Agenda Provide a background on radiation and the effects of radiation exposure Discuss the appropriate use of CT imaging in pregnancy Clinical scenarios 3
4. Why should I listen? Knowing types, number and cost of imaging services provided is important Imaging is on the rise Worldwide estimates from 2000-2007 show 3.6 billion medical procedures with ionizing radiation Deployed guidelines are in place to protect patients, improve quality of care, and reduce inter-practice practitioner variability Synthesize new information with previous knowledge K I KIDS D S 4
5. Imaging Use Statistics In the United States in 2006: 377 million diagnostic and interventional radiology exams 18 million nuclear medicine exams Usage in the U.S. alone accounted for: ~12% of the world’s radiologic procedures ~50% of the world’s nuclear medicine procedures Some skew in the data, ex: Germany does not performnuclear medicine stress testing because it’s not reimbursed Radiologic and Nuclear Medicine Studies in the United Statesand Worldwide: Frequency, Radiation Dose and Comparisonwith other Radiation Sources 1950-2007. Metler, FA ea al.Radiology 2009; 253:520-531 5
6. CT is not a benign procedure “On the basis of risk estimates and data on CT use from 1991 to 1996, it has been estimated that about 0.4% of all cancers in the United States may be attributable to the radiation from CT studies. By adjusting this estimate for CT use, this estimate might now be in the range of 1.5 – 2.0%.” Computed tomography – an increasing source of radiation exposure. Brenner DJ, Hall EJ. NEJM 2007 Nov 29;357(22):2277-2284. 6
7. CT is not a benign procedure “From an individual standpoint, when a CT is justified by medical need, the associated risk is small relative to the diagnostic information obtained. However, if it is true that one third of all CT scans are not justified by medical need, and it appears to be likely, perhaps 20 million adults and, crucially, more than 1 million children per year in the United States are being irradiated unnecessarily.” Computed tomography – an increasing source of radiation exposure. Brenner DJ, Hall EJ. NEJM 2007 Nov 29;357(22):2277-2284. 7
8. Average Exposure Amounts by Procedure 1 rad = 0.01 gray (Gy) = 0.01 Sievert (Sv) = 1 rem (roentgen-equivalent man)and 0.001 rad = 1 mrad = 0.01 mGy 8
9. Typical Effective Dose Values *The equivalent dose to a tissue is found by multiplying the absorbed dose, in gray, by a dimensionless "quality factor" Q, dependent upon radiation type, and by another dimensionless factor N, dependent on all other pertinent factors. The Sv attempts to reflect the biological effects of radiation as opposed to the physical aspects, which are characterized by the absorbed dose, measured in gray. 9
10. “Effective dose is not the risk for any one individual. Due to inherent uncertainties and oversimplifications involved, effective dose should not be used for epidemiologic studies or for estimating population risks.” How Effective is Radiation Dose as a Predictor of Radiation Risk? McCollough, CH et al. AJR 2010; 194:890-896 10
11. Controversy Risks Associated with Low Doses and Low Dose Rates of Ionizing Radiation: Why Linearity May (Almost) Be The Best We Can Do? Little MP et al. Radiology 2009; 251:6-12 v. The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data. Tubiana M et al. Radiology 2009; 251:13-22 11
12. Linearity Model “In summary, excess cancer risks obtained in the Japanese atomic bomb survivors and in many medically and occupationally exposed groups exposed at low or moderate doses are generally statistically compatible. For most cancer sites, the dose response in these groups is compatible with linearity over the range observed.” Risks Associated with Low Doses and Low Dose Rates of Ionizing Radiation: Why Linearity May (Almost) Be The Best We Can Do? Little MP et al. Radiology 2009; 251:6-12 12
13. Linearity is inconsistent with reality “Irradiated cells protect themselves (a) by immediate defense, repair and damage removal mechanisms and (b) by delayed and temporary protection also renewed DNA damage, irrespective of its causes – that is through adaptive responses… The fears associated with concept of the linear no-threshold model and the idea that any dose, even the smallest, is carcinogenic lack scientific justification.” The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data. Tubiana M et al. Radiology 2009; 251:13-22 13
14. Radiation Exposure in Pregnancy Most common adverse effects seen from high-dose radiation are intrauterine growth restriction, microcephaly, and mental retardation The risk of mental retardation appears to take at least a dose of 20 rads. This risk is 40% following a dose of 100 rads and increases to 60% with a dose of 150 rads. Microcephaly and fetal growth restriction have been reported at doses between 10 and 20 rads American College of Obstetricians and Gynecologists (ACOG) and the American College of Radiology (ACR) both state that exposures of less than 5 rads do not increase the risk for anomalies (which leaves the range of 5 to 10 rads as being the gray zone) 14
15. So what about risk? “The risk burden of radiation exposure to the fetus has to be carefully weighed against the benefits of obtaining a critical diagnosis quickly and using a single tailored imaging exam.” Imaging in Pregnant Patients: Examination Appropriateness. Weisler KM et al. RadioGraphics 2010; 30:1215-1233 15
17. ACR states that theoretical risks are unlikely at doses <100 mGy (1 Gy = 100 rad) 17
18. What about iodinated contrast in the pregnant patient? “Based on neonatal TSH measurements in a small number of patients, we found no ill effect of iodinated contrast agents on neonatal thyroid function after in utero exposure… In conclusion, based on neonatal TSH measurements in a small number of patients, the IV administration of water soluble nonionic iodinated contrast agents to pregnant patients has no subsequent effect on neonatal thyroid function.” Neonatal Thyroid Function After Administration of IV Iodinated Contrast Agent to 21 Pregnant Patients. Atwell TD et al. AJR 2008; 191:268-271 18
19. When is CT indicated? The most common indications for urgent CT during pregnancy are: Appendicitis For first and second trimester pregnancies US and/or MR should be performed prior to obtaining a CT Pulmonary embolism CT pulmonary angiogram exposes the fetus to less radiation than a VQ scan. CT should be the initial modality. Renal colic US is the initial study of choice. Trauma US may be sufficient for the initial imaging evaluation of a pregnant patient who has sustained trauma, but CT should be performed if serious injury is suspected. 19
20. Appendicitis Appendicitis Most common cause of surgical abdomen in pregnancy 50-70 per 1000 patients Slightly higher rate in second trimester Leukocytosis in pregnancy can confound the diagnosis (as high as 16,000 in second trimester) Ultrasound is typically done first. Some institutions, including Woodhull, will also perform MRI Small case series showed appendix not visualized in 22 of 23 pregnant patients in 3rd trimester due to gravid uterus* If indeterminate or MRI is not available, a CT is done using oral and IV contrast 20 *Abdominal CT during pregnancy for suspected appendicitis: a 5-year experienceat a maternity hospital. Shetty MK et al. Semin US CT MR 2010; 31:8
24. Pulmonary embolism Pulmonary embolism (PE) is the leading cause of maternal mortality in the developed world Pregnancy is associated with an increased risk of pulmonary embolism. A pregnant patient with symptoms of deep venous thrombosis (DVT) should undergo compressive ultrasound or impedance plethysmography. Diagnostic testing for pulmonary embolism (PE) should include either V/Q scanning or helical computed axial tomographic pulmonary angiography (HCTPA) Both can be performed safely during pregnancy). The greater accuracy of HCTPA, along with findings that the average fetal radiation dose is consistently lower than V/Q scanning for all 3 trimesters, illustrates that HCTPA is more appropriate for evaluating a pregnant patient in whom you suspect acute PE. 24 *Pulmonary embolism in pregnancy. Bourjeily, G et al. The Lancet, February 2010, Volume 375, Issue 9713, Pages 500 - 512
26. Urolitiasis Calculi in pregnancy are uncommon (1/200 to 1/2000) Urolithiasisduring pregnancy can be serious, causing preterm labor in up to 40% of affected women The frequency of stone localization is twice as higher in the ureter than in the renal pelvis or calyx, but there is no difference between the left and right kidney or ureter. Ultrasound is done first but, if not helpful, CT is done to rule out stone and look for other causes of flank pain. If CT is done, low dose, non-contrast CT is sufficient for diagnosis No difference between 100%, 50% and 25% examinations in detecting stones > 3 mm (reducing tube charge from 100 -> 30 mAs) Urinary Calculi: Radiation Dose Reduction of 50% and 75% at CT-Effect on Sensitivity. Ciaschini MW et al. Note that noise increases at low dose and makes detection of stones< 3 mm easy to miss. However, these stones and not likely to be clinically significant 26
30. Trauma The severity of injury determines workup but priority is given to maternal survival CT is used as needed in the chest and abdomen Most common uterine injury is placental abruption, which occurs in up to 40% of patients with severe injury. Uterine rupture is rare 30
35. In Summary “The risk burden of radiation exposure to the fetus has to be carefully weighed against the benefits of obtaining a critical diagnosis quickly and using a single tailored imaging exam.” Imaging in Pregnant Patients: Examination Appropriateness. Wieseler KM et al. RadioGraphics 2010; 30:1215-1233 35
Based on switching around numbers, you end up with 2% getting cancer because of a CT. Ludacris. You’re making this assumption based on extrapolation from the Hiroshima event. Hiroshima was a unique experience, it’s not like getting a CT. There are many different doses. We irradiated a population that was very ill. The average person in Japan was malnourished. Radiation effects on a malnourished population are significantly different than the effects on a healthy population but that’s never really looked at.
Effective does is a very important concept.People take effective dose and they turn that into people getting cancer and what happens with an individual patient. You have to be careful what numbers mean.Estimates are derived from simulation models.
People take effective dose and they turn that into people getting cancer and what happens with an individual patient. You have to be careful what numbers mean.Estimates are derived from simulation models.
The sievert (symbol: Sv) is the SI derived unit of dose equivalent. It attempts to reflect the biological effects of radiation as opposed to the physical aspects, which are characterised by the absorbed dose, measured in gray. It is named after Rolf Sievert, aSwedish medical physicist famous for work on radiation dosage measurement and research into the biological effects of radiation.The röntgen (roentgen) equivalent in man (or mammal[1]) or rem (symbol rem) is a unit of radiation dose equivalent. It is the product of the absorbed dose in rads and a weighting factor, WR, which accounts for the effectiveness of the radiation to cause biological damage.1 rem = 0.01 SvRad = dose causing 0.01 joule of energy to be absorbed per kilogram of matter.
There are many reasons for acute abdomen. Give lots of oral, wait 90 – 120 minutes and you can
Cecum and distal bowel are well filled.
Placenta enhancing, very bright, homogeneous. Fetus in place with fluid in the uterine cavity
Placenta, bright, fairly homogeneous enhancement
Extensive acute central PE with “saddle embolus” extending into both central pulmonary arteries in a 72-year-oldman. Contrast material–enhanced 16–detector row CT yielded coronal volume renderings in (a) anterocranial and (b) anteriorperspectives, which allow intuitive visualization of the location and extent of embolus (arrows).
Three-dimensional reconstructed CT scan image of a ureteral stent (left kidney, indicated by yellow arrow) in a 26-year-old male. There is a kidney stone in the pyelum of the lower pole (highest red arrow) and one in the ureter beside the stent (lower red arrow).
Look at the placenta, see the mild enhancement. It’s abnormal. There’s some bleeding in the abdominal wall. Rupture, injury to placenta. Monitored 12-13 hours, kid went into distress and required c-section. 36 weeks gestation.
Placenta abruptia
Coronal views of same patient – placenta abruptia – critical example of how a CT allowed to make a very specific diagnosis