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1 CB **** -*** -** -* ** *** **** itle: Comparison of radiation absorbed dose in target organs in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography and computed tomography Authors: Panjnoush M. Assitant Professor*, hokri A. Assitant Professor**, Hosseini Pouya M.***, Deevband M.**** Address: *Department of Oral and Maxillofacial Radiology, chool of Dentistry, ehran University of Medical ciences **Department of Oral and Maxillofacial Radiology, chool of Dentistry, Hamedan University of Medical ciences ***Dosimetry group head of Atomic Energy Organization of Iran ****upervision, inspection and Enforcement section of Atomic Energy Organization of Iran Background and Aim: he objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CB) and computed tomography (). Materials and Methods: hermoluminescent dosimeters (LD) were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. he Promax (PLANMECA, Helsinki, Finland) unit was selected for, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,UA) was selected for examination. he average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ. Results: he average absorbed dose for panoramic ranged from 0.08 (Buccal skin) to 0.08 (submandibular gland), linear tomography ranged from (Lens) to (submandibular gland), CB ranged from 0.22 (thyroid glad) to (parotid gland) and in ranged from (sublingual gland) to.424 (submandibular gland). otal effective dose in CB is 5 times greater than panoramic and 4 times greater than linear tomography, and in, 0 and 22 times greater than panoramic and linear tomography, respectively. otal effective dose in is 6 times greater than CB. Conclusion: For obtaining -dimensional (D) information in maxillofacial region, CB delivers the lower dose than, and should be preferred over a medical imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation. Key Words: Absorbed dose; hermoluminescent dosimetry (LD); Cone bean computed tomography * :: ab_sh80@yahoo.com: : 11

2 ... ( ) : RANDO 14. CB (LD) : ( PLANMECA) Promax. ( ) piral Hispeed/Fxi CB. ( ) 08 ( ) 08 : ( ) 1/144 ( ) 22 CB ( ) 510 ( ) CB. ( ) /424 ( ) 2/495 CB CB :...() Plain film CB Planmeca (D Finland) CB ( ). (Radiation Analog Dosimetry ystem) 10 RANDO.(1). CB (LD) : 88/06/2 : 88/06/20 : 88/04/10 : x 100. x %1/5-2.(1) x..(2) (CB) Cone Beam Computed omography.. 114

3 RANDO - LD 5 LD 2 CB LD..(4) LD. (background) LD. LD LD reader ) LD analyzer. Planchet Fraction irradiated ( (H ).(1) ( H (W R ) = W R D ) RANDO -1 (LD) 4 (chips) ) (16 84 ). ( PLANMECA) Promax CB 8 60 (16 Full maxilla & mandible scan ) 0 piral Hispeed/Fxi 2 ) 54 8 (high resolution ) (.(2 ) (59 40 RANDO CB

4 .... Dunn.. 4..(P>) CB CB.(P<).(P<) (49) -1 Fraction irradiated %16/5 %16/5 %5 (H ) (E). (E). E = W H W ICRP 2007 :.(2) Kruskal-Wallis (94) ICRP (W ) W 20 W 1990 W remainder remainder remainder - 10 (remainder) 116

5 ) CB () - Linear omo CB otal Linear omo CCB otal Linear omo CB otal Linear omo CB otal Linear omo CB otal Linear omo CB otal. ( (5) Ludlow (7) Clark ) Danforth (6). ((9) ilva Ivanovic..(7) 0 / / /220 2 /814 0 / /08 0 / /8595 / / / / /1446 / /199 0 / /6 0 / / / /08 0 /17 0 / /61 0 /778 0 / /048 0 /425 2 / / / /171 0 / / / / /288 0 / / / / /665 0 / / / / /12 0 / / /972 0 / / / / / /500 0 /44 0 /858 0 / /06555 CB 4 6 CB CB. 9/5 /5 CB 52 62/ CB CB 117

6 Version, Ivanovic CB Ludlow Promax.( CB high resolution Low Dose.. CB CB LD LD Field Of View (FOV). CB. FOV %0 (11) FOV. %5-10 Palomo FOV FOV. CB CB. FOV FOV CB. 1- Brenner DJ, Hall EJ. Computed tomography an increasing source of radiation exposure. N Engl J Med. 2007; 57(22): Bushong stewart C. Radiologic science for technologists. 8 th ed. United tates: Mosby; (8) Fung Chau / canora x sharp thin-slice.(8) 7 -scan CBCR 5 6 Ludlow Mah (6) (9) ilva. (9) Ivanovic (8) Fung Chau (4) Ivanovic Ludlow (10) Ludlow ) Promax D 67 mall adult ( Large adult ) Promax : - Ludlow JB, Davies-Ludlow LE, Brooks L. Dosimetry of two extraoral direct imaging devices: Newom cone beam and Orthophos Plus D panoramic unit. Dentomaxillofac Radiol. 200; 2(4): Ludlow JB, Davies-Ludlow LE, Brooks L, Howerton WB.

7 Dosimetry of CB devices for oral and maxillofacial radiology: CB Mercuray, Newom G and i-ca. Dentomaxillofac Radiol. 2006; 5(4): () -5 ingle, Double emulsion ilva MA, Wolf U, Heinicke F, Bumann A, Visser H, Hirsch E. Cone beam computed tomography for routine orthodontic treatment Planning: a radiation dose evaluation. Am J Orthod Dentofacial Orthop. 2008; 1(5):640.e Danforth RA, Clark DE. Effective dose from radiation absorbed during a Panormic examination with a new generation machine. Oral urg Oral Med Oral Pathol Oral Radiol Endod. 2000; 89(2): Chau AC, Fung K. Comparision of radiation dose for implant imaging using conventional spiral tomography, computed tomography and cone beam computed tomography. Oral urg Oral Med Oral Pathol Oral Radiol Endod. 2009; 107(4): Ludlow JB, Ivanovic M. Comparative dosimetry of dental CB devices and 64-slice for oral and maxillofacial radiology. Oral urg Oral Med Oral Pathol Oral Radiol Endod. 2008; 106(1): Mah JK, Danforth RA, Bumann A, Hatcher D. Radiation absorbed in maxillofacial imaging with a new dental computed tomography device. Oral urg Oral Med Oral Pathol Oral Radiol Endod. 200; 96(4): Palomo JM, Rao P, Hans MG. Influence of CB exposure conditions on radiation dose. Oral urg Oral Med Oral Pathol Endod. 2008; 1(6):