• A previous diagnosis of histologically confirmed WHO grade 3 or grade 4 glioma

• Radiologically (MRI) confirmed tumor relapse/progression ≥ 12 weeks since completed radiotherapy or suspicion of recurrence where inclusion in the theranostic part of study could be indicated

• Must be ≥ 18 years old

• Written informed consent for study participation

• Negative pregnancy test no longer than 14 days prior to enrollment

• Life expectancy \> 12 weeks

• Karnofsky performance status ≥ 70% (must be able to care for self after radionuclide therapy)

• High tumor uptake on diagnostic imaging with 68Ga -PSMA.

• Tumor not amendable for radiotherapy or surgery, and treating oncologist think that there are no other preferable systemic therapy options (e.g temozolomide, PCV or lomustine monotherapy).

• Women of childbearing potential (WOCBP) defined as fertile, following menarche and until becoming post-menopausal unless permanently sterile must use adequate contraception. Permanent sterilization methods include hysterectomy, bilateral salpingectomy or bilateral oophorectomy. Adequate contraception in the current study will be the following:

• o Combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation:

⁃ Intravaginal

⁃ transdermal

⁃ Progestogen-only hormonal contraception associated with inhibition of ovulation:

⁃ oral

⁃ injectable

⁃ implantable

⁃ intrauterine device (IUD)

⁃ intrauterine hormone-releasing system ( IUS)

⁃ bilateral tubal occlusion

⁃ vasectomised partner

⁃ sexual abstinence

• Patient accept not to receive any other tumor directed treatment before 8 weeks after each 177Lu-PSMA injection.