Ashwathanarayana et al. 2017). A bicentric study by Prasad et al. (2010) indicated

the superiority of ⁶⁸Ga-DOTANOC PET/CT in the detection and management of

NENs with unknown primary sites (Prasad and Baum 2010).

Metaiodobenzylguanidine (mIBG) coupled with the theranostic pair of ¹²³I/¹³¹I

has been of immense utility in the detection and treatment of NENs, especially

neuroblastomas and pheochromocytoma-paragangliomas (Bombardieri et al. 2010;

Decarolis et al. 2013; Schmidt et al. 2008). Treatment of advanced neuroblastomas

with ¹³¹I-mIBG has shown response rates of 20–40%, with an acceptable toxicity

profile with/without chemotherapy followed by stem-cell rescue (Zhou et al. 2015).

As previously discussed, the development of PSMA-based ligands for diagnosis

and therapy has been a game changer in prostate cancer. The primary PSMA-based

ligands in current use include PSMA-11 (⁶⁸Ga-based), PSMA-I&T (imaging and

therapy), PSMA-1007 and DCFPyL (¹⁸F-based), ^99mTc-PSMA, and PSMA-617

(therapy with ¹⁷⁷Lu), among others (Prasad et al. 2016a; Singh et al. 2021). A

biodistribution study in prostate cancer using ⁶⁸Ga-PSMA-11 is shown (Fig. 7.1).

A randomized controlled trial of mCRPC patients treated with either 177Lu-PSMA-

617 radioligand therapy (RLT) or cabazitaxel showed more frequent PSA-based

responses in the RLT arm (66% vs 37%) with lesser incidence of Grade 3 or

4 adverse events (33% vs 53%) (Hofman et al. 2021).

Angiogenesis which is an essential step in tumor growth and metastasis is a useful

pathway for molecular targeting. αvβ3 integrin targeting using RGD peptides (argi-

nine-glycine-aspartate),

labelled

with

68Ga,

is

used

for

the

detection

of

neo-angiogenesis (Fig. 7.2) and can be more accurate in detection of malignancies

such as breast and thyroid carcinoma in comparison to ¹⁸F-FDG (Parihar et al. 2018f,

Fig. 7.1 A known case of castration-resistant metastatic prostate carcinoma with ⁶⁸Ga-PSMA-11

PET/CT showing diffuse disseminated skeletal metastases involving the multiple bones of the axial

and proximal appendicular skeleton

100

B. Singh et al.