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Titolo:
DOSIMETRY OF TRANSMISSION MEASUREMENTS IN NUCLEAR-MEDICINE - A STUDY USING ANTHROPOMORPHIC PHANTOMS AND THERMOLUMINESCENT DOSIMETERS
Autore:
ALMEIDA P; BENDRIEM B; DEDREUILLE O; PELTIER A; PERROT C; BRULON V;
Indirizzi:
CEA,SERV HOSP FREDERIC JOLIOT,DEPT RECH MED,DIRECT SCI VIVANT,4 PL GEN LECLERC F-91406 ORSAY FRANCE CEA,SERV HOSP FREDERIC JOLIOT,DEPT RECH MED,DIRECT SCI VIVANT F-91406ORSAY FRANCE HOP VAL DE GRACE,NUCL MED SERV PARIS FRANCE CEA,SERV RADIOPROTECT INSTALLAT,SERV PROTECT RAYONNEMENTS,UNITE GEST SECUR PROTECT SACLAY FRANCE
Titolo Testata:
European journal of nuclear medicine
fascicolo: 10, volume: 25, anno: 1998,
pagine: 1435 - 1441
SICI:
0340-6997(1998)25:10<1435:DOTMIN>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
POSITRON EMISSION TOMOGRAPHY; ATTENUATION CORRECTION; LABELED RADIOPHARMACEUTICALS; HUMAN BIODISTRIBUTION; LINE SOURCE; SPECT; EQUIVALENT; ACCURACY; TL-201; PET;
Keywords:
POSITRON EMISSION TOMOGRAPHY; SINGLE-PHOTON EMISSION TOMOGRAPHY; TRANSMISSION MEASUREMENTS; RADIATION DOSE; THERMOLUMINESCENT DOSIMETERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
20
Recensione:
Indirizzi per estratti:
Citazione:
P. Almeida et al., "DOSIMETRY OF TRANSMISSION MEASUREMENTS IN NUCLEAR-MEDICINE - A STUDY USING ANTHROPOMORPHIC PHANTOMS AND THERMOLUMINESCENT DOSIMETERS", European journal of nuclear medicine, 25(10), 1998, pp. 1435-1441

Abstract

Quantification in positron emission tomogrpahy (PET) and single photon emission tomographic (SPET) relies on attenuation correction which is generally obtained with an additional transmission measurement. Therefore, the evaluation of the radiation doses received by patients needs to include the contribution of transmission procedures in SPET (SPET-TM) and PET (PET-TM). In this work we have measured these doses for both PET-TM and SPET-TM. PET-TM was performed on an ECAT EXACT HR+ (CTI/Siemens) equipped with three rod sources of germanium-68 (380 MBq total) and extended septa. SPET-TM was performed on a DST (SMV) equipped with two collimated line sources of gadolinium-153 (4 GBq total). Two anthropomorphic phantoms representing a human head and a human torso, were used to estimate the doses absorbed in typical cardiac and brain transmission studies. Measurements were made with thermoluminescent dosimeters (TLDs, consisting of lithium fluoride) having characteristicssuitable for dosimetry investigations in nuclear medicine. Sets of TLDs were placed inside small plastic bags and then attached to different organs of the phantoms (at least two TLDs were assigned to a given organ). Before and after irradiation the TLDs were placed in a 2.5-cm-thick lead container to prevent exposure from occasional sources. Ambient radiation was monitored and taken into account in calculations. Transmission scans were performed for more than 12 h in each case to decrease statistical noise fluctuations. The doses absorbed by each organ were calculated by averaging the values obtained for each corresponding TLD. These values were used to evaluate the effective dose (ED) following guidelines described in ICRP report number 60. The estimated ED values for cardiac acquisitions were 7.7x10(4)+/-0.4x10(-4) mSv/MBq . h and 1.9x10(-6)+/-0.4x10(-6) mSv/MBq . h for PET-TM and SPET-TM. respectively. For brain scans, the values of ED were calculated as 2.7x10(-4)+/-0.2x10(-4) mSv/MBq . h for PET-TM and 5.2x10(-7)+/-2.3x10(-7) mSv/MBq . h for SPET-TM. In our institution, PET-TM is usually performedfor 15 min prior to emission. SPET-TM is performed simultaneously with emission and usually lasts 30 and 15 min for brain and cardiac acquisitions respectively. Under these conditions ED values, estimated for typical source activities at delivery time (22000 MBq in SPET and 555 MBq for PET), were 1.1x10(-1)+/-0.1x10(-1) mSv and 1.1x10(-2)+/-0.2x10(-2) mSv for cardiac PET-TM and SPET-TM respectively. For brain acquisitions, the ED values obtained under the same conditions were 3.7x10(-2)+/-0.3x10(-2) mSv and 5.8x10(-3)+/-2.6x10(-3) mSv for PET-TM and SPET-TM respectively. These measurements show that the dose received by apatient during a transmission scan adds little to the typical dose received in a routine nuclear medicine procedure. Radiation dose, therefore, does not represent a limit to the generalised use of transmissionmeasurements in clinical SPET or PET.

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Documento generato il 06/07/20 alle ore 05:30:27