Tamara N. Oei, M.D.Paul B. Shyn, M.D.

Usha Govindarajulu, Ph.D.

Richard Flint, M.D.

Senior Research PresentationFebruary 26, 2010

Increasing rate of obesity◦ Epidemic◦ Known health effects

Bariatric surgery has proven to be one of the most effective and definitive solutions

Known complications and risks with bariatric surgery 9-23 %, mortality 0.1-0.3%

Post bariatric surgery imaging plays important role in evaluating complications, especially since clinical exams are often inconclusive

WHAT IS THE RADIATION DOSE ACQUIRED IN THIS POPULATION?◦ Mostly female

◦ Young population

Cohort: 100 lap RYGB and 100 lap band patients Retrospective Medical records and imaging studies reviewed Number of CT and fluoroscopic exams tabulated

for follow-up period of 2.5 years Clinically significant positive findings recorded Excluded: unrelated exams, plain radiographs, Included: outside exams when documented,

routine 24 hour post op exams

Abdominopelvic CT:

◦ mean DLP determined from 19 studies where this info available from protocol display.

◦ Effective dose = mean DLP x 0.017 mSv/mGy-cm

PECT: 20mSv from literature

UGI series: 4 mSv from literature

Student t test for unpaired data

Non-linear regression model was employed with cumulative dose as the outcome adjusted by gender, age, type of surgery, and BMI in separate univariate models

Multivariate analysis was not performed because of the high correlation of BMI with type of surgery.

Cum dose: 4 to 156 mSv

Mean dose: 20 ± 20 mSv

> 50 mSv: 7 pts

% dose from CT: 77 %

4 to 46 mSv

11 ± 11 mSv

0 pts

41 %

Non-linear regression analyses univariate models

Undergoing RYGB higher BMI

were each significant predictors of increased cumulative dose

35% (24/68) of CT scans16% (14/86) of UGI series

24% (6/25) of CT scans22% (35/161) of UGI series

*None of UGI series after routine 24 post op studies were positive

RY

GB

Ban

d

Indications for study Positive findings

CT Nausea/vomiting, pain, s/p mesh for hernia, LLQ pain, abnormal LFTs, r/o jejunojejunostomy obstruction, fever, post reduction, follow up fluid collection, hypoglycemia, RUQ pain, question leak, desaturation, emesis, question obstruction, SBO, renal colic, flank pain, skin ecchymosis

Small bowel hernia (1), mild sigmoid diverticulitis (1), SBO (6), abdominal hernia (3), fluid collections (8), pouchitis (1), appendicitis (1), internal hernia (1), gastrogastric fistula (1), LUQ hematoma (1)

Fluoroscopy Routine 24 hours post operation, weight gain, pain with eating, question fistula, post endoscopy

Delayed passage through the gastrojejunostomy, obstruction at gastrojejunostomy, obstruction at jejunojejunostomy, ileus

Indications for study Positive findings

CT Shortness of breath, question leak, liver contusion, reflux, abdominal pain, r/o leak, fever, nausea/vomiting, no bowel movement, desaturation, hematocrit drop, LLQ pain

Liver contusion (1), atelectasis (1), subcutaneous abscess (1), ventral hernia (1), rectus hematoma (1), low band position (1)

Fluoro Routine 1 day post operation, status post revision, nausea/vomiting, weight gain

Obstructed, reflux, slow emptying, paraesophageal hernia, vertical orientation of the band, band slippage, gastric pouch hiatal hernia

internal hernia (1)

SBO (6)

obstruction

RYGB and inc BMI a/w more studies

Positive finding rate was 23%

For RYGB none of the fluoro studies were positive after POD 1

Most of patients are female

Avg age of 41 yrs

BEIR VII: 1:100 persons could be expected to develop a cancer in their lifetime from a single dose of 100 mSv (42:100 from other causes unrelated to radiation)

Linear-no-threshhold

10 mSv may cause cancer in 1:1000 pts

Younger patients: TEEN-LABS, 200 patients younger than 19 years old undergoing RYGB

Mostly female (84%), women are subject to a slightly increased risk relative to men of developing solid tumors secondary to radiation exposure

Adapted from the International Commission on Radiological Protection: Recommendations. Annals of the ICRP Publication 60. Oxford, Pergamon Press, 1990

7/100 RYGB pts received > 50 mSv (~2500 CXR) 1/100 RYGB pt received > 100 mSv (~5000 CXR) Highest dose in band group was 46 mSv 1 CXR = 0.02 mSv Background radiation = 3 mSv/yr

In addition to known complications, potential risks a/w DMR in the post-operative period should also be considered

Possible that pts who do not undergo bariatric surgery will later develop complications from obesity that could prompt similar or even greater numbers of radiological exams

Radiation risks are easily overlooked in the clinical setting since the carcinogenic effects of ionizing radiation take many years to manifest and causation is generally not provable on an individual basis

How would be radiation dose change with patient size?

How does patient size limit image quality and diagnostic interpretation?

How often are other complications discovered at surgery or endoscopy that were not evident by radiology?

While the risks-to-benefit ratio may be justified, strategies to minimize radiation dose in this patient population should be pursued.

Judicious use of radiologic tests should be emphasized.

Appropriate technique factors should be applied for all radiologic exams according to ALARA

Research Mentor: Paul Shyn, MD

Richard Nawfel, PhD (physicist)Richard Flint, MD (surgeon)Usha Govindarajulu (statistician)

Tamara N. Oei, Paul B. Shyn, Usha Govindarajulu, Richard Flint. (2009) Diagnostic Medical Radiation Dose in Patients After Laparoscopic Bariatric Surgery.

Obesity Surgery Online publication date: 25-Oct-2009.

Brenner D, Hall E. Computed tomography—an increasing source of radiation exposure. N Engl J Med 2007; 357: 2277-2284. Health risks from exposure to low levels of ionizing radiation—BIER VII. Washington, DC: National Academies Press, 2005. Brenner D, Doll R, Goodhead, D, et al. Cancer risks attributable to low doses of ionizing radiation: assessing what we really know. Proc Natl Acad Sci

2003; 100: 13761-13766. Overweight and obesity. Centers for Disease Control and Prevention, Department of Health and Human Services, 2009. (Accessed January 26, 2009, at

http://www.cdc.gov/nccdphp/dnpa/obesity/). Ogden C, Carroll M, Curtin L, et al. Prevalence of overweight and obesity in the United States, 1999-2004. JAMA 2006; 295: 1549-1555. Elder K, Wolfe B. Bariatric surgery: a review of procedures and outcomes. Gastroenterology 2007; 132: 2253-2271. Parikh MS, Laker S, Weiner M, et al. Objective comparison of complications resulting from laparoscopic bariatric procedures. J Am Coll Surg 2006; 202:

252-261. Tice JA, Karliner L, Walsh J, et al. Gastric banding or bypass? A systematic review comparing the two most popular bariatric procedures. Am J Med 2008;

121: 885-893. Livingston, EH. Procedure incidence and in-hospital complication rates of bariatric surgery in the United States. Am J Surg 2004; 188: 105-110. Sovik TT, Erlend TA, Kristinsson J, et al. Establishing laparoscopic roux-en-y gastric bypass: perioperative outcome and characteristics of the learning

curve. Obesity Surgery 2009; 19: 158-165. Santry HP, Gillen DL, Lauderdale DS. Trends in bariatric surgical procedures. JAMA 2005; 294: 1909-1917. Rosenthal RJ, Szomstein S, Kennedy C, et al. Laparoscopic surgery for morbid obesity: 1,001 consecutive bariatric operations performed at the bariatric

institute, Cleveland Clinic Florida. Obesity Surgery 2006; 16: 119-124. Campos GM, Ciovica RC, Rogers SJ, et al. Spectrum and risk factors of complications after gastric bypass. Arch Surg 2007; 142: 969-975. Filip JE, Mattar SG, Bowers SP, et al. Internal hernia formation after laparoscopic roux-en-y gastric bypass for morbid obesity. Am Surg 2002; 68: 640-

643. Merkle EM, Hallowell PT, Crouse C, et al. Roux-en-y gastric bypass for clinically severe obesity: normal appearance and spectrum of complications at

imaging. Radiology 2005; 234: 674-683. European Guidelines on Quality Criteria for Computed Tomography, EUR 16262 EN, May 1999 (Accessed June 9, 2008, at

http://www.drs.dk/guidelines/ct/quality/index.htm). Hurwitz LM, Reiman RE, Yoshizumi TT, et al. Radiation dose from contemporary cardiothoracic multidetector CT protocols with an anthropomorphic

female phantom: implications for cancer induction. Radiology 2007; 245: 742-750. Huda, W and Slone, R. Review of Radiologic Physics. 2nd ed. 2003: p 80 ICRP Publication 60: 1990 Recommendations of the International Commission on Radiologic Protection. International Commission on Radiological

Protection. Oxford, Pergamon Press, 1990. Inge TH, Zeller M, Harmon C, et al. Teen-longitudinal assessment of bariatric surgery: methodological features of the first prospective multicenter study

of adolescent bariatric surgery. J Pediatr Surg 2007; 42: 1969-1971. Preston D, Shimizu Y, Pierce D, et al. Studies of mortality of atomic bomb survivors. Report 13: solid cancer and noncancer disease mortality: 1950-1997.

Radiat Res 2003; 160: 381-407. Amis E, Butler P, Applegate K, et al. American college of radiology white paper on radiation dose in medicine. J Am Coll Radiology 2007; 4: 272-84. Lee CL, Haims AH, Monico EP, et al. Diagnostic CT scans. Radiology 2004; 231: 393-98. Martin D, Semelka R. Health effects of ionizing radiation from diagnostic CT. Lancet 2006; 367: 1712-1713.