Radiation exposure of the Italian population from diagnostic radiology and nuclear medicine examinations

Gaetano Compagnone1, Faustino Bonutti2, Stefano De Crescenzo3,Anna Dipilato4, Daniele Giansanti5, Alessandro Lazzari6, Paola Angelini7,

Sara Domenichelli1, Renato Padovani2

1Medical Physics Department, S. Orsola Malpighi University Hospital, Bologna (I),

2Medical Physics Department, S. Maria della Misericordia University Hospital, Udine (I), 3Medical Physics Department, Niguarda Cà Granda Hospital, Milano (I), 4Medical Physics

Department, University of Perugia (I), 5Istituto Superiore di Sanità, Roma (I), 6Medical Physics Department, USL2 Hospital, Lucca (I), 7Regional Health Service Emilia-Romagna,

Bologna (I)

Workshop on European Population Doses from Medical Exposure24-26 April 2012, Athens, Greece

In the European Union many studies have been implemented to quantify the contribution of medical procedures to the ionizing

radiation exposure of the population

In spite of the fact that the Italian health level is similar to that of other European countries where the population radiation dose from

medical exposure was already estimated, in Italy this evaluation was not performed yet

INTRODUCTION

The present study was carried out by collecting data related to both the dose and the frequency of the main diagnostic radiology and nuclear medicine procedures in Italy for estimating:

frequency of procedurescollective effective doseper caput dose

to the Italian population

Regional Health Autorities every 5 years (2001, 2006, 2011) should evaluate dosesto the population from medical exposures and send them to the Ministry of Health

The survey included 5 Italian regions:Emilia-Romagna, Friuli Venezia Giulia, Lombardia, Toscana, Umbria (accounting for approximately 30% of the Italian population)

The included radiology procedures in 2006 (reference year) covered several broad categories:

PROJECTION RADIOGRAPHY: Chest/Thorax; Cervical, Thoracic and Lumbar spine; Mammography; Abdomen; Pelvis and hip

RADIOGRAPHY AND FLUOROSCOPY: Ba meal and Ba enema; Intravenous urography

INTERVENTIONAL RADIOLOGY: Cardiac angiography; Percutaneous Transluminal Coronary Angioplasty

COMPUTED TOMOGRAPHY: CT head; CT neck; CT chest; CT spine; CT abdomen; CT pelvis

+ 33 examinations in NUCLEAR MEDICINE

MATERIALS AND METHODS

For each procedure were requested to each region both the frequency and the dose.The metric of the latter was selected depending on the type of examination:

Entrance Skin Dose in projection radiography

Kerma Area Product in interventional radiology

Entrance Skin Air Kerma and Average Glandular Dose in mammography

Dose Length Product in computed tomography

Administered Activity in nuclear medicine

If a region was not able to provide data for a specific examination, the results were interpolated on the basis of the other regions data (weighted mean by the number of examinations)

Effective doses per examination were estimated using appropriate conversion coefficients and, finally, data linearly extrapolated to the whole Italian population, to assess collective effective dose and per caput effective dose

Variations in the terminology adopted by the

Hospitals for describing the different types

of examinations:

“CT abdomen” what is exactly?

Country: Number of inhabitants: (in millions) 60.626Year:

The "TOP 20 list" RP154 Specific exams included in exam types *)Total number

per yearannual frequency per

1000 pop

1 Chest/Thorax 87.12.1 87.13.2 87.16.1 87.17.1 11,942,928 196.992 Cervical spine 87.22 1,809,056 29.843 Thoracic spine 87.23 961,964 15.874 Lumbar spine (inc.LSJ) 87.24.1 87.24.2 2,774,049 45.765 Mammography 87.37.1 87.37.2 4,534,795 74.806 Abdomen 88.19 1,612,561 26.607 Pelvis & hip 4,189,262 69.108 Ba meal 7.62 87.62.1 87.62.2 87.62.3 87.62.4 87.66 173,745 2.879 Ba enema 87.65.1 87.65.2 274,853 4.53

10 Ba follow-through 88.26 na na

11 IVU87.73 87.74.1 87.74.2 87.75.1 87.76 87.76.1 87.77 87.79 221,418 3.65

12 Cardiac angiography 263,879 4.35

13 CT head87.03 87.03.1 87.03.2 87.03.3 87.0341 87.0342 87.03.5 87.03.6 87.03.7 2,934,812 48.41

14 CT neck 155,298 2.5615 CT chest 87.41 87.41.1 87.42.3 1,273,627 21.0116 CT spine 88.38.1 88.38.2 88.90.3 735,344 12.1317 CT abdomen 88.01.1 88.01.2 88.01.3 88.01.4 88.01.5 88.01.6 1,809,500 29.8518 CT pelvis 88.38.05 138,655 2.2919 CT trunk na na20 PTCA 149,154 2.46

Italy2006

“Ba follow-through” examinations are included in “Ba meal”

“CT trunk” examinations are included in “CT Chest” and “CT abdomen” because this examination is counted as 2 examinations (chest and abdomen)

RESULTS AND DISCUSSION

Mean E/exam(mSv)

Annual collective effectivedose per 1000 pop (mSv)

1 Chest/Thorax 0.09 17.732 Cervical spine 0.20 5.973 Thoracic spine 0.60 9.524 Lumbar spine (inc.LSJ) 0.53 24.255 Mammography 0.25 18.706 Abdomen 0.66 17.567 Pelvis & hip 0.77 53.218 Ba meal 2.00 5.739 Ba enema 6.50 29.4711 IVU 1.60 5.8412 Cardiac angiography 7.96 34.6513 CT head 1.60 77.4514 CT neck 2.24 5.7415 CT chest 7.92 166.3816 CT spine 6.27 76.0517 CT abdomen 8.61 256.9818 CT pelvis 7.80 17.8420 PTCA 20.93 51.49

For Radiology, the highest dose/procedure was found in Percutaneous Transluminal Coronary Angioplasty (20.9 mSv).The annual collective effective dose received by the whole Italian population amounted to

53,021 man Sv from Radiology

For the PET/CT examination the dose contribution from the CT part is omitted.

For Nuclear Medicine, the highest dose/procedure was found in I-131 Adrenal cortical scintigraphy (59.4 mSv).The annual collective effective dose received by the whole Italian population amounted to

4,246 man Sv from Nuclear Medicine

The most frequent procedures are Chest/Thorax (11,942,928

examinations/year) in radiology and Tc-99m Bone imaging (280,509 examinations/year) in nuclear medicine.

As far as the examinations under consideration are concerned, the estimated total number of examinations in Italy was 35,954,900 and 874,696 for radiology and nuclear medicine, respectively.

The annual collective effective dose received by the whole Italian

population amounted to 57,267 man Sv

The per caput dose was 0.94 mSv per inhabitant in 2006,(Italy population was 60.626 million)

The uncertainties at 95% confidence level were calculated according to the Dose DataMed2 criteria: in radiology

procedures, the total relative uncertainties were 9.3% and

11.4% for frequency and collective dose, respectively.

This study collected different regional surveys and made homogeneous the available data according to the DoseDataMed2 criteria with an acceptable statistical significance.

In Italy, this evaluation represents the first national estimation of frequency and population dose from diagnostic radiology and nuclear medicine examinations.

The next step could be to extend the same methodology to other regions and to increase the number of examinations, in order to reduce the uncertainties both in frequency and in dose.

CONCLUSIONS