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How to estimate conceptus dose from radiographic, fluoroscopic and fluoroscopically guided interventional procedures Georgia Solomou, Medical Physicist.

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Presentation on theme: "How to estimate conceptus dose from radiographic, fluoroscopic and fluoroscopically guided interventional procedures Georgia Solomou, Medical Physicist."— Presentation transcript:

1 How to estimate conceptus dose from radiographic, fluoroscopic and fluoroscopically guided interventional procedures Georgia Solomou, Medical Physicist MSc Department of Medical Physics, University Hospital of Heraklion, Crete 8 th ECMP, September 2014, Athens

2  When a detailed dose assessment is needed  Available tools to estimate conceptus radiation dose  CONCERT Project  Conclusion Contents

3 Radiation and pregnancy Thousands of pregnant women are exposed to ionizing radiation Lack of knowledge may lead to unnecessary termination of pregnancies “No safe level” is a sweeping statement Radiation exposure should be medically appropriate

4 Is a detailed dose assessment always needed? No if: gestational age less than 2 weeks gestational age less than 2 weeks conceptus dose is low (conceptus is located out of the primary beam) conceptus dose is low (conceptus is located out of the primary beam)

5 Conceptus Dose(mGy) TERMINATION of pregnancy at conceptus doses of less than 100 mGy is not justified based upon radiation risk. ICRP publication 84: Conceptus dose estimation Dose > 10 mGy Dose > 10 mGy But when a detail assessment of conceptus radiation dose is needed? But when a detail assessment of conceptus radiation dose is needed? 10 mGy50 mGy100 mGy

6 When 10 mGy is exceeded? Examination “Typical estimate” conceptus dose (mGy) Reported range (mGy) Chest Radiography< Abdomen Pelvis Lumbar Spine42-40 Hip fractures0.16- Cardiac Catheter Ablation0.6- Kyphoplasty T93- Therapeutic ERCP

7 When 10 mGy is exceeded? Examination “Typical estimate” conceptus dose (mGy) Reported range (mGy) Chest Radiography< Abdomen Pelvis Lumbar Spine42-40 Hip fractures0.16- Cardiac Catheter Ablation0.6- Kyphoplasty T93- Therapeutic ERCP Barium enema Uterine fibroid embolization42- Kyphoplasty L5105- Pedicle screw fixation L Transureteral stent44- Cholangiography Varicocele embolization15.8 Dauer et al, JVIR, 2012

8 Which are the available tools for a detailed dose assessment?

9 Dosimeters - Patient models TLD MOSFET

10 Monte Carlo Simulation  A general purpose, three-dimensional general geometry, time- dependent, coupled neutron-photon-electron code  It is supported, on a variety of platforms including personal computers.  It has been widely used for medical physics applications   Input file: energy spectra, geometry, mathematical phantoms, materials and tallies.  Mathematical anthropomorphic phantoms are generated using BODYBUILDER software (White Rock Science, White Rock, NM).

11 … Monte Carlo  Output: Normalized conceptus dose /reference dose

12 PCXMC- Dose Calculation  Only at the first postconception weeks PCXMC 2.0, STUK-TR 7, Radiation and Nuclear Safety authority, 2012

13 How can we estimate conceptus dose in every day clinical practice?

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16 AP, PA Chest projections Dc= f (AP thickness) 1 st trimester 2 nd trimester 3 rd trimester Damilakis et al, Eur. Radiol, 2003

17 Limitations The existing studies do not include:  All performed projections  The depth of the conceptus at the first trimester,  All radiological examinations  Especially in fluoroscopically guided interventional procedures the existing studies are limited

18  Conceptus Dose Estimation by radiological examinations  Risks for fatal childhood cancer estimation

19 RADIOGRAPHS ExaminationsProjectionsField Size (cm)TrimesterskVpFiltration Abdomen AP PA 36X43 1 ST, 2 ND, 3 RD Chest AP PA LAT 36X43 1 ST, 2 ND, 3 RD Kidneys AP PA 36X24 1 ST, 2 ND, 3 RD Lumbar Spine AP LAT LAT LSJ LPO RPO 36X43 18X24 24X30 1 ST, 2 ND, 3 RD Pelvis/Colon AP PA AP Hip Joint 36X43 24X35 1 ST, 2 ND, 3 RD Thoracic Spine AP LAT 24X43 20X49 1 ST, 2 ND, 3 RD Urinary BladderAP 24X21 24X18 1 ST, 2 ND, 3 RD

20 Abdomen radiography Pregnant patient at the 1 st trimester of gestation  0.055mGy/mAs (FSD=100cm, 80kV)  Output =0.055mGy/mAs (FSD=100cm, 80kV) Examination ParametersAP Abdomen Tube potential (kV)80 Focus to skin Distance(cm)100 mAs33 Filtration (mm Al)3 Fetus Depth (cm)8 How conceptus dose was estimated?

21 kVpdepth(cm) filtration (mm) D FETUS = Σ (ESD I *NFD I ) 0.454

22 FLUOROSCOPY ExaminationsProjectionsField Size (cm)TrimesterskVpFiltration Barium Enema AP Colon/Pelvis AP Rectum LAO Colon LAO Flexure LAT Rectum LPO Colon LPO Rectum PA Pelvis/Colon PA Rectum RAO Colon RAO Flexure RAO Rectum 24x30 15x15 35x35 28x35 17x17 35x35 19x19 40x40 15x15 35x35 28x35 19x19 1 ST Barium Follow Through AP Small Intestine PA Small Intestine 22x18 1 ST, 2 ND, 3 RD Barium Meal AP Duodenum AP Stomach AP Upper Stomach LAO Stomach LAT Stomach LPO Duodenum LPO Stomach PA Duodenum PA Stomach PA Upper Stomach RAO Duodenum RAO Stomach 15x15 18x22 15x15 21x21 19x24 19x19 21x21 15x15 18x21 15x15 19x19 21x21 1 ST Barium Swallow LAO Oesophagus LAT Throat LPO Oesophagus RAO Oesophagus 13x47 18x24 13x47 1 ST, 2 ND, 3 RD Cardiac CatheterizationAP Heart LAO Heart LAT Heart PA Heart RAO Heart 12.5x ST, 2 ND, 3 RD

23 Barium Enema  0.055mGy/mAs (FSD=100cm, 80kV)  Output =0.055mGy/mAs (FSD=100cm, 80kV) How conceptus dose was estimated? Pregnant patient at the 1 st trimester of gestation Examination Parameters AP Colon /Pelvis AP Rectum RAO Colon RAO Rectum LAO Colon LPO Rectum Tube potential (kV) Focus to skin Distance(cm) 80 mA3.5 Fluoroscopy time(min) Filtration (mmAl) 3.5 Contribution30%10%15% Total DAP (Gycm 2 )80

24 AP Pelvis/Colon kVp filtration(mm) AP Rectum kVp filtration(mm) LAO Colon kVp filtration(mm) LPO Rectum kVpfiltration(mm) RAO Colon kVpfiltration(mm) RAO Rectum kVpfiltration(mm) D fetus =5 cGy

25 Cardiac Procedures ExaminationsProjectionsField Size (cm)TrimesterskVpFiltration Pacemaker insertion LPO 30 Heart PA Heart RPO Heart 14x x x14 1 ST, 2 ND, 3 RD PCA/CALAO 40(±15) LAO 40-CAUDAL 30(±10) LAO45-CRANIAL 20(±10) LLAT(±10) PA(±15) PA(±15)-CAUDAL30(±5) PA-CRANIAL 30(±10) RAO20(±10)-CAU20(±5) RAO20(±10)-CRA20(±5) RAO 30 (±5) 12.5X ST, 2 ND, 3 RD Al Cu Interventional Procedures ExaminationsProjections Field Size (cm) TrimesterskVpFiltration Ballons PA Abdomen both PA Abdomen right PA Abdomen left 27.14x ST, 2 ND, 3 RD Al Cu Vena CavaSubrenal placement Supernal placement Guidance iliac & jug 15x8 6.31x ST, 2 ND, 3 RD Al Cu

26 Vena Cava filter placement Pregnant patient at the 2 nd trimester of gestation Examination ParametersCatheteriasm jugular VenographyGuidance jugular Suprenal filter placement Venography Tube potential (kV) Focus to skin Distance(cm) mA Fluoroscopy time(min)23242 Filtration (mmAl)5mm Al Contribution (%) Total DAP (Gy cm 2 )48 How conceptus dose was estimated?  mGy/(mAs×min) (FSD=100cm, 110kV)  Output = mGy/(mAs×min) (FSD=100cm, 110kV)

27 Catheterisation jugular FILTRATION3 mm AL 4 mm AL 5 mm AL kVp mm Cu Venography FILTRATION3 mm AL 4 mm AL 5mm Al kVp mm Cu Guidance jugular FILTRATION3 mm AL 4 mm AL 5 mm AL kVpmm Cu Suprenal placement FILTRATION3 mm AL 4 mm AL 5mm Al kVp mm Cu D fetus = 4 mGy

28 Conceptus Radiogenic Risk Dauer et al, JVIR, 2012, McCollough, Radiographics 2007 Barium Enema 0.49% 0.07% Vena Cava Filter Placement 0.12% Conceptus Dose(mGy) Possibility of childhood cancer %

29 Conclusion  Conceptus doses from extra-abdominal procedures are low. Conceptus risk is negligible compared to the benefit for the mother.  A detailed dose assessment is needed in examinations where conceptus is irradiated primarily.  Each physicist has the tools to estimate conceptus radiation dose and the associated radiogenic risk.

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