68Ga/177Lu-PSMA Theranostics in Recurrent Grade 3 and Grade 4 Glioma

Inclusion Criteria: * 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. Exclusion Criteria: * Estimated GFR \< 30 mL/min * Platelet count \<75 x109 /L * White blood cells ≤ 2.5 x 109/L * Neutrophil count \< 1.5 x109 /L * Hb \< 8.0 g/dL * Albumin ≤ 25 g/L * Uncontrollable symptomatic epilepsy refractory to standard medication * Pacemakers or defibrillators not compatible with 3T MRI * No ability to obtain informed consent (e.g. due to severe dysphasia or cognitive deficits). * Breastfeeding * Pregnancy * Hypersensitivity to the active substance or to any of the excipients * Urinary and fecal incontinence (patient cannot have diaper needs) * Significant medical or psychiatric illness that, in the investigator's opinion, would compromise the patient's ability to tolerate this therapy * If previous radiotherapy and/or radionuclide therapy have resulted in absorbed doses \>=23 Gy to any of the kidneys, or \>= 25 Gy to any of the parotids, an individual assessment will be made by the nuclear medicine physician and medical physicist if patient can be included to the therapy part of the study. * Concurrent investigational drugs or experimental therapy must be stopped at least 4 weeks prior to study entry * Unwilling to accept potential challenge with xerostomia