Medical Neutron Science

03 Neutron Activation Analysis03 Neutron Activation Analysis

The use of NAA techniques for medical applications was first reported in 1964 for measurement of sodium in the body

J A d S B O b RW T li D N J R d L S l d JWJ. Anderson, S.B. Osborn, R.W. Tomlinson, D. Newton, J. Rundo, L. Salmon, and J.W.Smith, Neutron‐Activation Analysis in Man in Vivo. a New Technique in Medical Investigation,Lancet 2, 1201–1205, (Dec 5 1964)..         

N 23 N 24Na23 + n Na24 ( 1.37; 2.75 MeV)

Between 1968 and 1972, Chamberlain Between 1968 and 1972, Chamberlain reported the measurement of body calcium and sodium in the body and described and sodium in the body and described techniques for whole-body NAA and pulsedNAA. NAA.

48Ca + n  49Ca +  (3.1  MeV ) ( )

M.J. Chamberlain, J.H. Fremlin, D.K. Peters, and H. Philip, Total body calcium bywhole body neutron activation: new technique for study of bone disease, Br. Med. J. 2,581–3, Jun 8 1968.

Cohn and Dombrowski reported the measurement of calcium, sodium chlorine, , ,nitrogen, and phosphorus in the humanbody through in vivo NAA.y g

Since then, NAA and PGNAA have been used ,for a variety of applications, such as the measurement of nitrogen, carbon and g ,oxygen, cadmium, and manganese in the body and in trace element research to yidentify cancerous tissue.

Inelastic neutron scatter analysis (INSA) i f 14 M V using fast neutrons use 14 MeV neutrons

from a (d,T) sealed-tube neutron generator d i h l b d b to determine whole body carbon content as a

measure of energy expenditure in the body.K. Kyere, B. Oldroyd, C.B. Oxby, L. Burkinshaw, R.E. Ellis, and G.L. Hill, Thefeasibility of measuring total body carbon byfeasibility of measuring total body carbon by counting neutron inelastic scatter gammarays, Phys. Med. Biol. 27, 805–17 (Jun 1982).

The use of nuclear resonance The use of nuclear resonance scattering (NRS) is used for detection of iron in the liver and in the heart using of iron in the liver and in the heart using an indirect method of nuclear excitation by gamma rays generated through neutron capture (INSA).t oug eut o captu e ( S )

Recently 14 MeV neutrons has been Recently, 14 MeV neutrons has been used for in vivo measurement of liver i th h INSA d NRSiron through INSA and NRS.

Neutron Stimulated EmissionNeutron Stimulated Emission Computed Tomography: 

A New Technique for SpectroscopicA New Technique for SpectroscopicMedical Imagingg g

Radiation therapy activation analysis

2002 Prompt‐gamma spektroskopi (PGS)

• Mätning av infångningsgamma utsända från bor och väte i patient under bestrålning med epitermiskaväte i patient under bestrålning med epitermiskaneutroner.

n + p              D2 + gamma

2002 Prompt‐gamma spektroskopi (PGS)

• Mätning av infångningsgamma

HPGe-detektorMCA+Dator

infångningsgamma utsända från bor och väte i patient underväte i patient under bestrålning.

Räk h ti h t i• Räknehastigheten i detektorn för linjerna k l t till

1000

10000

nts

kan relateras till borkoncentrationen in‐i

100Cou

n

vivo. 100 500 1000 1500 2000 2500

Energi [keV]

Tidigare resultat med PGSTidigare resultat med PGS

• Mättider kring 3 min.

• Borkoncentrationer kring 5 ppm.Borkoncentrationer kring 5 ppm.

• Vid homogen borfördelning blir noggranheten 3% (1 SD)3% (1 SD). 

Neutron stimulated emission Neutron stimulated emission computed tomography (NSECT), was pioneered at Duke University in was pioneered at Duke University in 2003 by the late Dr. Carey E. Floyd Jr. for the purpose of diagnostic medical imaging.g g

A neutron incident on a sample travels freely along its projected path until it collides with an atomic nucleus of projected path until it collides with an atomic nucleus of an element present in the sample. If the collision with the atomic nucleus results in inelastic scatter, the nucleus can get excited to one of its quantized higher-energy states. The excited nucleus is often unstable and will rapidly deca to a lo e ene g state emitting a gamma a decay to a lower energy state, emitting a gamma-ray photon with energy equal to the difference of the two states These energy states are well established for most states. These energy states are well established for most elements and isotopes and are mostly unique for the elements commonly found in the body. Therefore, the energy of the emitted gamma photon can be treated as a unique signature of the emitting element. Tomographicdetection and analysis of gamma lines in the emitted detection and analysis of gamma lines in the emitted spectrum provide quantitative information about the spatial distribution of the element in the samplespatial distribution of the element in the sample

Spectrum for Fe with the sample‐out spectrum subtracted from the sample‐in tspectrum.

Geometry of the phantom imaged in the tomography experiment.

Reconstructed image from the NSECT acquisition of the sample.

The vertical outer bars represent copper while the diagonal inner (gray) bars represent iron.

The vertical outer regions represent copper while the diagonal inner region represents iron.

Each bar measures 0.6 cm by 6 cm by 2.5 cm

Each element was reconstructed separately and then combined

56Fe

63Cu

63Cu 56Fe

Gamma energy spectrum from the iron‐copper phantom showing spectral linesfrom six transitions in 56Fe and 63Cu:1. 63Cu from 1st excited state to ground state; energy 660 keV2. 56Fe from 1st excited state to ground state; energy 847 keV3. 63Cu from 2nd excited state to ground state; energy 962 keV4. 56Fe from 3rd to 2nd excited state; energy 1239 keV5. 56Fe from 4th to 2nd excited state; energy 1811 keV6. 63Cu from 6th to 1st excited state; energy 1864 keV

6 MeV Neutron Stimulated Emission 6 MeV Neutron Stimulated Emission6 MeV Neutron Stimulated Emission Computed Tomography NSECT spectrum of a benign breast sample showing elements identified through gamma spectroscopy

6 MeV Neutron Stimulated Emission Computed Tomography NSECT spectrum of a malignant  breast sample showing elements identified through gammaidentified through gamma spectroscopy. elements identified through gamma spectroscopy.

The Dose analysis can be summarized in the following three steps:

(a) a Monte‐Carlo simulation is used to estimate two parameters for an incident( ) pneutron beam – the number of neutrons that interact in the volume ofinterest and the average energy deposited per interacting neutron,

(b) the resulting energy deposited in the volume is converted from MeV to J/kgusing the knownmass of the volume to give the absorbed energy in Gray (Gy),And

(c) the absorbed energy is multiplied by the quality factor for neutrons (10) andthe weighting factor for the organ of interest to give the effective dose

l ( )equivalent in Sieverts (Sv).

Patient dose was calculated for h t bt i d d each gamma spectrum obtained and

was found to range from between 0.05 and 0.112 mSv depending on the number of neutrons. This the number of neutrons. This simulation demonstrates that NSECT has the potential to NSECT has the potential to noninvasively detect breast cancer th h fi i t t through five prominent trace element energy levels, at dose levels comparable to other breast cancer screening techniques.cancer screening techniques.

NSECT represents an exciting new imaging modality that has the potential for application in both medical and biological research.At the department of Medical Radiation Physics in Lund we already have a lot of expertisein the different field of knowledge necessary to establish Neutron Stimulated Emissionin the different field of knowledge necessary to establish Neutron Stimulated EmissionComputed Tomography NSECT in practice. 

What we are missing are laboratories for neutron Exposure. A prototype of the g p p ypNSECT acquisition system has been developed and built at Duke University using a Van‐de‐Graaff accelerator and HPGe detectors.  That would be able to establish in Lund aswell,  in collaboration with our friends at  Nuclear Physics.  For furthe establishment at ESS 

The use of nano particles of iron or other elements labelled with biologically active moleculesor antibodies or lymphocytes labelled with nanoparticles in combinations withy p y pNeutron Stimulated Emission Computed Tomography NSECT opens up for a completelynew field of Nano‐Nuclear medicine.

This could be one important leg for establishing Medical Neutron Beam at ESS