Comparação da dose absorvida de dois protocolos de varredura tomográfica em exame de PET/CT
DOI:
https://doi.org/10.15392/bjrs.v6i2B.394Keywords:
Dosimetry, Computed Tomography, PET/CTAbstract
Positron emission tomography (PET) associated with computed tomography (CT) allows the fusion of functional and anatomical images. When compared with other diagnostic techniques PET/CT subjects the patients to higher radiation dose levels because two radiation modalities in a single exam are used. In this study, the absorbed doses were evaluated in 19 organs from the CT scan. Radiochromic filmstrips were correctly positioned into the Alderson anthropomorphic phantom, masculine version. For this evaluation two Whole-body CT scan protocols were compared, one protocol for generating images with lower resolution aiming only the anatomical mapping (1), and a second protocol with higher resolution images for diagnostic purposes (2). There was an increase of up to 600 % in the absorbed dose in the hypophysis and cervical spine when comparing the protocols, with an average increase of around 230 % in other organs. The CT organ dose in patients submitted to PET/CT scanning is higher in the protocol used for diagnosis. Considering the higher cost of PET/CT examination and its applications in the diagnosis of minor alterations, in some cases it is necessary that CT scan has diagnostic quality, not only for the anatomical mapping, even knowing the dose increase for the patient. In these cases, the argument for using a higher patient doses technique is based on the Principle of Justification. It is worth emphasizing the importance of a careful evaluation of the need to perform the exam using protocol (2) for all patients, but only in essential cases.
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References
CZERNIN, J.; SCHELBERT, H. PET/CT imaging: facts, opinions, hopes, and questions. Journal of Nuclear Medicine, v. 45, n. 1 suppl, p. 1S-3S, 2004.
BROWNELL, L. G. A History of Positron Imaging. Physics Research Laboratory Massachusetts General, Hospital Division of Radiological Sciences, Massachusetts Institute of Technology. 1999.
CABREJAS, M. L. Tomografia em Medicina Nuclear. Editora Argentina, Argentina, 1999.
BEYER T., TOWNSEND D.W., BRUN T., KINAHAN P.E., CHARRON M., RODDY R., et al. A combined PET/CT scanner for clinical oncology. J Nucl Med. 2000; 41(8):1369–79.
BRIX, G.; BEYER, T. PET/CT. Nuklearmedizin, v. 44, p. S51-7, 2005.
QUINN, Brian et al. Radiation dosimetry of 18F-FDG PET/CT: incorporating exam-specific parameters in dose estimates. BMC medical imaging, v. 16, n. 1, p. 41, 2016.
MOORE, S.C.; PARK, M.. PET and PET/CT physics, instrumentation, and artifacts. 2012.
CZERNIN, J.; ALLEN-AUERBACH, M.; SCHELBERT, H. R. Improvements in cancer staging with PET/CT: literature-based evidence as of September 2006. Journal of Nuclear Medicine, v. 48, n. 1 suppl, p. 78S-88S, 2007.
HUANG, B.; LAW, M.M.W.; KHONG, P. Whole-body PET-CT scanning: Estimation of radiation dose and cancer risk. Radiology, v. 251, n. 1, p.166-174. 2009.
SANTANA, P.C. Doses e risco da radiação em pacientes submetidos a exames de corpo inteiro de 18F-FDG PET-CT para diagnóstico oncológico. 2014. 117f. Tese (Doutorado em Ciências e técnicas nucleares). Universidade Federal de Minas Gerais, 2014.
KAUSHIK, Aruna et al. Estimation of radiation dose to patients from 18FDG whole body PET/CT investigations using dynamic PET scan protocol. The Indian journal of medical research, v. 142, n. 6, p. 721, 2015.)
SOMERWIL, A.; VAN KLEFFENS, H. J. Experience with the Alderson Rando phantom. The British journal of radiology, v. 50, n. 592, p. 295-296, 1977
OLIVEIRA, Cássio Miri et al. Suggestion of a national diagnostic reference level for 18F-FDG/PET scans in adult cancer patients in Brazil. Radiologia Brasileira, v. 46, n. 5, p. 284-289, 2013.
ISP - International specialty products, 2010. Gafchromic XR catalogue. 8p.15.
GIADDUI, Tawfik et al. Characteristics of Gafchromic XRQA2 films for kV image dose measurement. Medical physics, v. 39, n. 2, p. 842-850, 2012.)
MOURÃO, A. P.; GONÇALVES JR, R. G.; ALONSO, T. C. Dose profile variation with pitch in head CT scans using gafchromic films. Recent Advances in Biomedical & Chemical Engineering and Materials Science, v. 1, p. 51-4, 2014.,
Abramoff M, Magelhaes P, Ram S: Image Processing with ImageJ. Biophotonics International. 2004, 11: 36-42.
ABRAMOFF, M. D.; MAGALHAES, P. J.; RAM, S. J. Image processing with ImageJ. Biophotonics Int. 11: 36–42. Google Scholar, 2004.
BERA, G. et al. Equivalent dose rate from patients after whole-body FDG-PET/CT. Médecine Nucléaire, 2017.
TSUKAMOTO, Eriko; OCHI, Shinji. PET/CT today: system and its impact on cancer diagnosis. Annals of nuclear medicine, v. 20, n. 4, p. 255, 2006.
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