On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics
Comparison is made of technologies of radiopharmaceuticals (RPC) production that are labeled with positron-emitting nuclides using a cyclotron and an electron accelerator (EA). It is shown that specific activities of RPC produced on EA are sufficient for the g-camera and PET diagnostics.
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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| Cite this: | On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics / A.S. Zadvorny // Вопросы атомной науки и техники. — 2011. — № 5. — С. 39-41. — Бібліогр.: 8 назв. — англ. |
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irk-123456789-1114742017-01-11T03:02:36Z On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics Zadvorny, A.S. Ядерно-физические методы и обработка данных Comparison is made of technologies of radiopharmaceuticals (RPC) production that are labeled with positron-emitting nuclides using a cyclotron and an electron accelerator (EA). It is shown that specific activities of RPC produced on EA are sufficient for the g-camera and PET diagnostics. Проведено порівняння технологій отримання радіофармпрепаратів (РФП), мічених позитрон-випромінюючими нуклідами, які отримуються на циклотроні та електронному прискорювачі (ЕП). Показано, що питомі активності РФП, які отримані на ЕП, достатні для діагностики на g-камері та для ПЕТ-досліджень. Проведено сравнение технологий получения радиофармпрепаратов (РФП), меченных позитрон-излучающими нуклидами, получаемых на циклотроне и электронном ускорителе (ЭУ). Показано, что удельные активности РФП, полученные на ЭУ, достаточны для диагностики на g-камере и для ПЭТ-исследований. 2011 Article On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics / A.S. Zadvorny // Вопросы атомной науки и техники. — 2011. — № 5. — С. 39-41. — Бібліогр.: 8 назв. — англ. 1562-6016 PACS: 87.62+n http://dspace.nbuv.gov.ua/handle/123456789/111474 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Ядерно-физические методы и обработка данных Ядерно-физические методы и обработка данных Zadvorny, A.S. On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics Вопросы атомной науки и техники |
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Comparison is made of technologies of radiopharmaceuticals (RPC) production that are labeled with positron-emitting nuclides using a cyclotron and an electron accelerator (EA). It is shown that specific activities of RPC produced on EA are sufficient for the g-camera and PET diagnostics. |
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On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics |
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On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics |
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On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics |
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On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics |
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on possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Ядерно-физические методы и обработка данных |
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On possibility of short-living positron-emitting nuclides production using electron accelerator for medical diagnostics / A.S. Zadvorny // Вопросы атомной науки и техники. — 2011. — № 5. — С. 39-41. — Бібліогр.: 8 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-08T02:13:05Z |
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ON POSSIBILITY OF SHORT-LIVING
POSITRON-EMITTING NUCLIDES PRODUCTION USING
ELECTRON ACCELERATOR FOR MEDICAL DIAGNOSTICS
A.S. Zadvorny∗
National Science Center ”Kharkov Institute of Physics and Technology”, 61108, Kharkov, Ukraine
(Received June 16, 2011)
Comparison is made of technologies of radiopharmaceuticals (RPC) production that are labeled with positron-emitting
nuclides using a cyclotron and an electron accelerator (EA). It is shown that specific activities of RPC produced on
EA are sufficient for the γ-camera and PET diagnostics.
PACS: 87.62+n
1. INTRODUCTION
Short-living positron-emitting nuclides 11C, 13N , 15O
and 18F are labels for pharmaceuticals used for di-
agnostics on a positron-emitting tomograph (PET).
Traditionally they are produced on a cyclotron by ex-
posing the targets to accelerated protons (18 MeV ) or
deuterons (9 MeV ) [1]. The target thickness does not
exceed 1 cm with a high specific activity. After irra-
diation the target is transported to the radiochemical
laboratory where the RPC is synthesized. The RPC
having been produced is injected to the patient and
then scanning is performed on the PET tomograph.
The activity injected to the patient amounts 3...5 mK
(1.8× 108 Bk).
The RPC quality is monitored and must satisfy
such demands as sterility, apirogeneity, chemical and
radiochemical purities. The cost of the targets used
for production of the above mentioned nuclides is
not high. The exception is the target for 18F pro-
duction that is formed in the 18O(p, n)18F reaction.
For this the water is used enriched with the 18O iso-
tope (0.2%) in the natural mixture, its content should
amount 70...90%. The cost of the diagnostics with
18F is determined by the cost of such water which is
produced in Ukraine as well.
The PET diagnostics allows one to find the local-
ization and size of new growths at the stage where
other known methods cannot reveal this yet. The
above mentioned nuclides emit positrons with dif-
ferent energies. As a result of positron interaction
with the medium electrons, the annigilation of these
particles happens with formation of two 511 keV
γ-quantums with the 180◦ angle of scattering which
are recorded by the counters forming the ring of the
PET scanner. The detecting system (a ring detector
containing up to 1000 counters) records less than 2%
of all irradiated γ-quantums. It is the low efficiency of
g quantum registration that results in a high activity
of RPC injected to patients.
2. THE POSSIBILITY OF USING AN
ELECTRON ACCELERATOR
We consider the possibility of using an electron ac-
celerator (linear one or microtron) for production
of above-mentioned positron-emitting nuclides and
manufacturing RPC on their basis. These nuclides
can be produced on an electron accelerator supplied
by the converter. The accelerated electrons gener-
ate γ-quantums (bremstralung) in the field of retard-
ing target nucleus (converter). The bremstrahlung
spectrum is continuous, and the maximum energy
of γ-quantums is (Emax −mec
2) where Emax is the
maximum energy of electrons. Such γ-quantums can
excite the (γ, n) reaction, its products being the nu-
clides necessary for diagnostics. As the neutron bond-
ing energy in the nucleus amounts about 8 MeV in
average, the thresholds of these reactions are of the
same value. The (γ, n) reaction cross-section is a
maximum at the energy 15...17 eV and drops to zero
at 25...27 eV . Therefore, the maximum energy of the
accelerated electrons should not exceed 30 MeV not
to excite the (γ, p), (γ, d), (γ, pn), (γ, pα) reactions
that will result in formation of impurity nuclides.
The cross-sections of these reactions amount tens mB
and are substantially less than cross-sections on pro-
tons and deuterons. The divergence of the beam
of γ-quantums in steradians is characterized by the
Θ value which is equal to the electron rest energy
mc2/electron maximum energy ratio. This quan-
tity determines the target diameter irradiated by the
γ-quantums. At least 95% of high-energy quantums
must hit the target. The peculiarities of investiga-
tions on the beams of bremstrahlung γ-quantums are
described in detail in [2], and data useful for exper-
∗Corresponding author E-mail address: zadvorny@kipt.kharkov.ua
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2011, N5.
Series: Nuclear Physics Investigations (56), p.39-41.
39
imentalists are in the monograph [3]. Photoneutron
sources are described in the monograph [4]. The lon-
gitudinal size of the target is determined by the free
path of γ-quantums, their slowing-down to the (γ, n)
reaction threshold. As the γ-quantums loose their
energy exponentially, the longitudinal size of the tar-
get, proceeding from the above mentioned data, is
determined by the length of e-fold γ-quantum en-
ergy decrease. Therefore, the size of photo-nucleus
target is 100...1000 times larger than that of cy-
clotron targets. This results in a low specific ac-
tivity and large volumes of the liquid preparations.
In this case, the intravenous injection is ruled out,
and the peroral RFP delivery or the radioactive air
inhalation are used. With this, the volume of the
liquid is 100...200 times larger than that of the in-
tervenous injection. The high penetrating ability of
γ-quantums that generate short-living radionuclides
allows one to use pharmaceutical preparations, such
as the water for injections, the glucose solution and
other medicinal forms. These forms can be used not
only for radionuclide production but as RPS as well.
In this case, all above mentioned RPS inspection de-
mands are ensured. The activity produced in pho-
tonuclear reactions was estimated theoretically and
experimentally by a number of authors [5-7]. The re-
sults of these works were compared with the data ob-
tained in NSC KIPT within the frames of the STCU
project [8]. Below Table is presented where the re-
sults obtained by different authors are compared.
Comparative data on isotopes production Isotope
Isotope Specific activity, Bk/gµA at 25 MeV
M.H. Mc Gregor G.L. Luts Our
[5] [6] experiment∗
11C 7.5 · 106 0.8 · 106 2.25 · 106
13N 3 · 106 1.4 · 106 3.36 · 106
15O 1.85 · 106 1 · 106 2.25 · 106
18F 1.85 · 106 0.75 · 106 1 · 107
∗beforesaturation
3. CONCLUSIONS
The data cited above show that the produced specific
activities of isotopes coincide by the order of mag-
nitude. The difference in the quantities at the fac-
tor 106 are explained by different experimental con-
ditions - convertor thickness, irradiated sample size,
its disposition in the bremstrahlung beam, distance
between the output foil and the convertor and be-
tween the convertor and the irradiated sample. On
electron accelerators regimes can be realized with cur-
rents amounting 20...50 mA. It is seen that activities
produced at currents 100 mA are sufficient for the
PET diagnostics. The maximum counting rate for
the γ-camera is limited by 5× 104 pulses/s. Such an
activity amounts about 25% of that injected to the
patient. Proceeding from the condition that only 25%
of the activity participate in the diagnostics process
and the injected radiation is extended over the 4π
geometry, 2 × 105 Bk should be injected to the pa-
tient. As is seen in the Table, such an activity is pro-
duced on the electron accelerators. The processes of
the peroral and respiratory activity injection are im-
portant because of a lower radiation loading on the
medical staff. The γ-camera enables to make diag-
nostics of most of human organs. Therefore, it is rea-
sonable to combine the PET-scanner and γ-camera.
References
1. M.V.Korsakov. Manual on PET Radiochemistry.
S.-Petersburg: ”Khimiya”, 2002, 180 p. (in
Russian).
2. O.V.Bogdankevich, F.A. Nikolaev. Operation
with Bremstrahlung Beam. M: ”Atomizdat”,
1964, 246 p. (in Russian).
3. V.P.Koval’ov. Secondary Radiations of Electron
Accelerators. M: ”Atomizdat”, 1979, 200 p. (in
Russian).
4. N.A.Vlasov. Neutrons. M: ”Nauka”, 1971, 551 p.
(in Russian).
5. M.H.McGregor. Linear Accelerators as Radioiso-
tope Producers // Nucleonics. 1957, v.15, p.176-
180.
6. G.L. Luts //Anal. Chem.. 1969, v.41, p.425.
7. H.P. Piltingsrud. Design of target system for pro-
ducing clinically useful quantities of oxygen-15
using an electron linear accelerator // Med. Phys.
1982, v. 9, N4, p.514-520.
8. G.L.Bochek, A.N. Dovbnya, A.S. Zadvornyj,
V.I.Kulibaba, A.A.Kaplij, V.D. Ovchinnik,
I.M.Prokhorets, A.V. Torgovkin, B.I. Shra-
menko. Production of short-living izotopes
on the EPOS accelerator of NSC KIPT for
positron-emission tomography // Problems
of Atomic Science and Technology. Series
”Nuclear-Physical Investigations”. 1999, N1(37),
p. 66-67.
40
ВОЗМОЖНОСТЬ НАРАБОТКИ КОРОТКОЖИВУЩИХ
ПОЗИТРОН-ИЗЛУЧАЮЩИХ НУКЛИДОВ НА ЭЛЕКТРОННОМ УСКОРИТЕЛЕ
ДЛЯ МЕДИЦИНСКОЙ ДИАГНОСТИКИ
А.С. Задворный
Проведено сравнение технологий получения радиофармпрепаратов (РФП), меченных позитрон-излуча-
ющими нуклидами, получаемых на циклотроне и электронном ускорителе (ЭУ). Показано, что удель-
ные активности РФП, полученные на ЭУ, достаточны для диагностики на γ-камере и для ПЭТ-
исследований.
МОЖЛИВIСТЬ ВИРОБЛЕННЯ КОРОТКОЖИВУЧИХ
ПОЗИТРОН-ВИПРОМIНЮЮЧИХ НУКЛIДIВ НА ЕЛЕКТРОННОМУ
ПРИСКОРЮВАЧI ДЛЯ МЕДИЧНОЇ ДIАГНОСТИКИ
А.С. Задворний
Проведено порiвняння технологiй отримання радiофармпрепаратiв (РФП), мiчених позитрон-випромiню-
ючими нуклiдами, якi отримуються на циклотронi та електронному прискорювачi (ЕП). Показано,
що питомi активностi РФП, якi отриманi на ЕП, достатнi для дiагностики на γ-камерi та для ПЕТ-
дослiджень.
41
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