Conventional radiographic exam, and childhood cancer risk: Cohort study

Author: Janet

There is no increased childhood cancer risk, with very low dose radiation through diagnostic imaging, which is consistent with model calculations.

The study is available in American Journal of Roentgenology. The long-term consequences of diagnostic ionizing radiation exposure in childhood is slightly less known. Current evaluations are made with models obtained chiefly through research of survivors of atom bombs, people that vary from present-day patients in many aspects, and the preliminary research objective was to quantify risk amongst young patients through radiography exam.

In a German university hospital, cancer occurrence in children that underwent diagnostic x ray exposures during year 1976-2003 were assessed by the researchers. They reorganized case-by-case radiation dosage for each, and classified results by referral criteria groups for all cancers.

Through 78,527-patient cohort, in the duration of 1980-2006, about 68 cancer incidence cases were recognized, in the German childhood cancer registry: except for 25 other, 9 lymphoma, 28 leukemia, and 6 tumors of the central nervous system were found. For all the cancers, the standardized incidence ratio was 0.97; through multivariate poisson regression – dose response relationships were evaluated.

Even though cancer incidence risk varied by primary referral criterion for radiographic examination, for 5 patients with metabolic/endocrine disease, a positive dose response relationship was noted.

Conclusion: There was no heightened cancer risk amongst children/youth, with very low dose radiation through diagnostic imaging, which is consistent with model calculations. The increased usage of computed tomography justifies further studies to evaluate related cancer risk.

Low-dose over contrast-enhanced abdominal CT: for acute appendicitis, in young adults

The diagnostic performance of low-dose CT is comparable to standard dose CT, to characterize/analyze appendicitis in young adults.




Acute appendicitis_CT scan
The medical research study was conducted by So Yeon Kim, MD; Kyoung Ho Lee, MD, PhD; Kyuseok Kim, MD, PhD; Tae Yun Kim, MD, PhD; Hye Seung Lee, MD, PhD; Seung-sik Hwang, MD, PhD; Ki Jun Song, PhD; Heung Sik Kang, MD, PhD; Young Hoon Kim, MD, PhD and Joong Eui Rhee, MD, PhD from the Departments of Radiology, Emergency Medicine, Seoul National University, Korea; Department of Social and Preventive Medicine, Inha University School of Medicine, Incheon, Korea; and Department of Biostatistics, Yonsei University College of Medicine, Seoul, Korea.

Appendicitis is an inflammation/rubor of the vermiform/cecal appendix. The research objective was to equate standard and low radiation doses in intravenous, contrast-enhanced abdominal CT scan, for identification of acute appendicitis in young adults.

The study comprised about 257 patients, suspected of appendicitis that passed through CT with standard/low radiation dose; through with Wilcoxon rank-sum test, Freeman-Halton statistics, and ROC curve analysis the diagnostic performance of CT was recorded and equated by, for appendicitis.

Of 44 standard dose and 55 low radiation dose examinations, one of the abdominal radiologists made primary report, which served as final report; for residual examination, on-call radiologists were requested that submitted over primary reports, and the abdominal radiologists then put forward final reports.

About primary reports – standard and low dose CT groups did not considerably vary in regions under the receiver operating characteristic curve, specificity or sensitivity, for detection of appendicitis; no considerable deviation could be established amongst two groups in confidence level, when diagnosing/debarring appendicitis in preliminary reports; identical results were marked for the final reports. The dose groups even did not substantially vary in terms of subsequent: appendiceal visualization/image, distinctive characterization of appendiceal perforation, sensitivity for substitution method/diagnoses etc.

Conclusion: the diagnostic performance of low dose computed tomography to that of standard-dose CT is comparable, for characterization of appendicitis in young adults.

Warning Signs and Lights "Radiation Producing Machines and Devices"

All "analytical x-ray equipment" must have the following items:

1. A clearly visible label, near any switch energizing an x-ray tube, which bears the radiation symbol and the words: "Caution: This Equipment Produces X-rays When Energized. To Be Operated Only By Authorized Personnel."
2. A clearly visible label, near the x-ray tube housing, which bears the radiation symbol and the words: "Caution: High Intensity X-ray Beam."
3. A clearly visible fail-safe* warning light, near any switch energizing an x-ray tube, labeled with these words: "X-ray On."
4. A clearly visible fail-safe warning light in a conspicuous place near the x-ray tube which indicates when the x-ray tube is producing x-rays.

*As used for the purposes of Section 16, "fail-safe" means that all failures of warning and safety systems that can reasonably be anticipated will cause the equipment to fail in a mode such that personnel are safe from exposure to radiation.

Requirements for Enclosed Beam X-ray Systems

An enclosed beam system is a system in which all possible x-ray paths are fully enclosed so that any part of the body cannot enter the enclosure. In addition to the general requirements found in paragraph 2 above, the following requirements must be met:

a. Safety Devices

There must be:

• Enough interlocks to prevent the generation of x-rays or the emergence of the primary beam when any section of the enclosure is opened during routine operation, alignment or maintenance.
• A chamber or coupled chambers enclosing the radiation source, sample, detector and analyzing crystal, which cannot be entered by any part of the body during normal operation.
• A sample chamber closure with a fail-safe interlock so that no x-ray beam can enter an open sample chamber.

b. Dose Limits

The equipment must be so constructed that the dose rate due to leakage radiation at 5 cm from any accessible surface does not exceed 0.25 mrem/hour during normal operation.

Pregnant nuclear medical technician

• The regulatory gestational radiation dose limit to a declared pregnant worker is 500 mrem a
• Nuclear Regulatory Commission regulations and some Agreement State regulations state that average exposure to a declared pregnant worker should be maintained, if possible, to 50 mrem/month.
• The average whole-body radiation dose for a nuclear medical technician is 400-600 mrem/year (National Council on Radiation Protection & Measurements Report 124).

Pregnant magnetic resonance imaging (MRI) Technologist

There is no evidence in the scientific literature that a standard diagnostic MRI performed on a person who is pregnant will cause fetal biological effects. The literature suggests that the strength of the magnetic resonance (MR) field at diagnostic levels does not affect DNA synthesis, cell cycle, or proliferation kinetics in a fetus. The Food and Drug Administration (FDA) and other regulatory agencies have strict limits on MRI field strengths at diagnostic levels.

Radiation workers Rdiation limit per year

A radiation worker is allowed to receive up to 5000 mrem (5 rem) each year as a result of exposure received on the job. In most states, the radiation dose to a fetus of a declared pregnant worker (a radiation worker who has told the Radiation Safety Officer of her pregnancy) must be kept below 500 mrem (0.5 rem) during gestation. It is also important to note that low levels of ionizing radiation are not foreign to our bodies. Each year the average U.S. citizen receives an exposure of approximately 300 mrem (0.3 rem) from natural radiation sources. If you have concerns regarding the situation in your specific facility, you might try to contact your facility’s Radiation Safety Officer.