title: Assessment of dose and DNA damages in individuals exposed to low dose and low dose rate ionizing radiations during computed tomography imaging.
abstract: OBJECTIVE
  Computed tomography (CT) is a frequently used imaging modality that contributes to a tenfold increase in radiation exposure to the public when compared to other medical imaging modalities. The use of radiation for therapeutic need is always rationalized on the basis of risk versus benefit thereby increasing concerns on the dose received by patients undergoing CT imaging. Therefore, it was of interest to us to investigate the effects of low dose and low dose-rate X-irradiation in patients who underwent CT imaging by recording the doses received by the eye, forehead and thyroid, and to study the levels of damages in the lymphocytes in vivo.
  
  
  METHODS
  Lithium manganese borate doped with terbium (LMB:Tb) thermo luminescence dosimeters (TLD) were used to record the doses in the patient's (n = 27) eye, forehead, and thyroid and compared with the dose length product (DLP) values. The in vivo DNA damages measured were compared before and after CT imaging using chromosomal aberration (CA) and micronucleus (MN) assays.
  
  
  RESULTS
  The overall measured organ dose ranged between 2 ± 0.29 and 520 ± 41.63 mGy for the eye, 0.84 ± 0.29 and 210 ± 20.50 mGy for the forehead, and 1.79 ± 0.43 and 185 ± 0.70 mGy for the thyroid. The in vivo damages measured from the blood lymphocytes of the subjects showed an extremely significant (p < 0.0001) increase in CA frequency and significant (p < 0.001) increase in MN frequency after exposure, compared to before exposure.
  
  
  CONCLUSIONS
  The results suggest that CT imaging delivers a considerable amount of radiation dose to the eye, forehead, and thyroid, and the observed increase in the CA and MN frequencies show low dose radiation effects calling for protective regulatory measures to increase patient's safety. This study is the first attempt to indicate the trend of doses received by the patient's eye, forehead and thyroid and measured directly in contrast to earlier values obtained by extrapolation from phantoms, and to assess the in vivo low dose effects in an Indian patient population undergoing CT procedures.
authors.affiliation: Department of Human Genetics, Sri Ramachandra University, Porur, 600 116 Chennai, India. Electronic address: karthikkanagaraj@hotmail.com.
authors.forename: Karthik
authors.initials: K
authors.lastname: Kanagaraj
authors.affiliation: Department of Human Genetics, Sri Ramachandra University, Porur, 600 116 Chennai, India. Electronic address: safabasheer88@gmail.com.
authors.forename: Safa
authors.initials: S
authors.lastname: Abdul Syed Basheerudeen
authors.affiliation: Department of Human Genetics, Sri Ramachandra University, Porur, 600 116 Chennai, India. Electronic address: tamizh096@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Tamizh Selvan
authors.affiliation: Radiation Safety Section, Radiation Safety Division, Indira Gandhi Center for Atomic Research, 603102 Kalpakkam, India. Electronic address: mtj@igcar.gov.in.
authors.forename: M T
authors.initials: MT
authors.lastname: Jose
authors.affiliation: Radiation Safety Section, Radiation Safety Division, Indira Gandhi Center for Atomic Research, 603102 Kalpakkam, India. Electronic address: anna@igcar.gov.in.
authors.forename: Annalakshmi
authors.initials: A
authors.lastname: Ozhimuthu
authors.affiliation: Department of Radiology, Sri Ramachandra University, Porur, 600 116 Chennai, India. Electronic address: smartsafa@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Panneer Selvam
authors.affiliation: Department of Radiology, Sri Ramachandra University, Porur, 600 116 Chennai, India. Electronic address: sudha@gmail.com.
authors.forename: Sudha
authors.initials: S
authors.lastname: Pattan
authors.affiliation: Department of Human Genetics, Sri Ramachandra University, Porur, 600 116 Chennai, India. Electronic address: venkip@yahoo.com.
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Perumal
mesh_terms: D001881:Borates / Q000737:chemistry; D002869:Chromosome Aberrations / Q000528:radiation effects*; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008094:Lithium / Q000737:chemistry; D008214:Lymphocytes / Q000378:metabolism / Q000528:radiation effects*; D008274:Magnesium / Q000737:chemistry; D015162:Micronucleus Tests; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D011839:Radiation, Ionizing; D011874:Radiometry / Q000295:instrumentation / Q000379:methods; D013725:Terbium / Q000737:chemistry; D014057:Tomography, X-Ray Computed / Q000009:adverse effects*
chemical_list: D001881:Borates; D013725:Terbium; D008094:Lithium; D008274:Magnesium
keywords: CT; DLP; DNA damages; Low dose radiation; TLD