I would use some imaging system. How do you induce prostate cancer?

I guess, You can test prostate specific antigen (PSA) with suitable antibody from the blood of the animal. So, collect the blood from the tail vein or nictitating membrane of the animal without sacrificing the animal.

Hello Simonetta 

Thanks for your answer, I induced the cancer by injecting the animals testosterone daily 2mg/Kg for 8 weeks and giving them PPT 3.4 mg/daily by gavaging them for eight weeks. I want to check the tumor development before kill the animals. 

 Thanks Tapan 

But do you know if PSA works with rats?

Many use 68Ga-PSMA ligand as tracer for PET/CT for detection of human prostate cancer

I found the following reference which may be helpful to you,

Mark A. Suckow, James Wheeler, and Min Yan. PAIII prostate tumors express prostate specific antigen (PSA) in Lobund-Wistar rats. Can J Vet Res. 2009 Jan; 73(1): 39–41.

Best wishes,

Tapan

As far as I know spontaneous prostate tumors in rat do not produce PSA, but I am not updated with the literature.

PCA 3 marker can be used

please go through this references

Masrudin, Mohamad: "Preventive effect of Pueraria mirifica on testosterone-induced prostatic hyperplasia in Sprague Dawley rats." in: Andrologia, 2015 (PubMed).

Peng, Liu, Chang et al.: "Action Mechanism of Ginkgo biloba Leaf Extract Intervened by Exercise Therapy in Treatment of Benign Prostate Hyperplasia." in: Evidence-based complementary and alternative medicine : eCAM, Vol. 2013, pp. 408734, 2013 (PubMed).

Nahata, Dixit: "Sphaeranthus indicus Attenuates Testosterone induced Prostatic Hypertrophy in Albino Rats." in: Phytotherapy research : PTR, 2011 (PubMed). Method employed by authors: ELISA

I was involved with studies of testis cancer transplanted to nude nice. Here we transplanted humen cancer subcutaneously. So you might have simillar options ir AVE SIMILAR OPTIONS IN YOUR SYSTEM, IMMUNE COMPETENT OR IMMUNE  your system. Immune competent or incopetent rats, human or rat prostate cancer.