Yttrium86

86Y can be produced on a biomedical cyclotron via the 86Sr(p,n)86Y nuclear reaction using isotopically enriched 86Sr foil or carbonate pellet [20]. The separation of 86Sr from the 86Y is carried out by dissolving the carbonate in an acidic solution and then co-precipitating the Sr with lanthanum. The precipitate is then dissolved and separated using anion exchange [20]. 86Y is appealing as an isotope (ti = 14.74 h) because of its potential use for evaluating dosimetry prior to 90Y radiotherapy.

With the current interest in small-animal PET imaging [21], a word should be said about the application of these metal radionuclides in such devices. One of the biggest constraints for these scanners is the positron range of the nuclide used. Many of the nuclides described in this chapter have P+max energies in excess of 1 MeV. Above this threshold, significant reduction in resolution is seen. One isotope, 64Cu, has demonstrated particular utility and promise in small-animal imaging. Its P+max energy of 646 keV puts it in the range of 18F, and the resolution of the images is comparable [22-24].

Table 11.2. Generator-produced metal PET isotopes [4].

Daughter Isotope

Daughter half-life

Daughter decay

Max ß+ energy

Parent Isotope

Parent half-life

Parent decay

mode (%)

(MeV)

mode(%)

128Cs

3.8 m

P+(61), EC(39)

2.90

128Ba

2.43 d

EC(100)

44Sc

3.92 h

P+(95), EC(5)

1.47

44Ti

48 y

EC(100)

62Cu

9.76 m

P+(98), EC(2)

2.91

62Zn

9.13 h

P+(7), EC(93)

82Rb

1.25 m

P+(96), EC(4)

3.15

82Sr

25 d

EC(100)

68Ga

68.3 m

P+(90), EC(10)

1.90

68Ge

275 d

EC(100)

52mMn

21.1 m

P+(98), EC(2)

1.63

52Fe

8.2 h

P+(57), EC(43)

110In

66 m

P+(71), EC(29)

2.25

110Sn

4.0 h

EC(100)

118Sb

3.5 m

P+(77.5), EC(22.5)

2.67

118Te

6.00 d

EC(100)

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