Effectiveness of Concurrent Ultra-Low-Dose Total-Skin Electron Beam Therapy and Brentuximab Vedotin Given Quarterly Over 12 Months for Patients With Mycosis Fungoides

To learn if a form of radiation therapy (called ultra-low-dose - total skin electron beam therapy \[ULD-TSEBT\]) in combination with brentuximab vedotin can help to control mycosis fungoides

Inclusion Criteria: 1. Biopsy-confirmed mycosis fungoides in stage I-IV (APPENDICES 3 AND 4); the presence of Sezary cells in the blood is acceptable at original diagnosis or at enrollment into the protocol, as long as the patient has current mycosis fungoides in the skin and the sesary cells in peripheral blood are \< 1000 cells/ microlitre at the time of enrollment. 2. Participants with relapsed/ refractory mycosis fungoides expressing at least 1% CD30 are eligible. 3. Previous systemic anticancer therapy must have been discontinued at least 1 week before treatment 4. In the case of myelosuppressive chemotherapy treatment may start once counts have recovered including absolute WBC\> 1000, platelets\> 50K. 5. Topical or systemic steroids (equivalent to 10 mg/day of prednisone) may be considered if the dose of such steroids has been constant and their discontinuation may lead to rebound flare in disease, adrenal insufficiency, and/or unnecessary suffering, after discussion with the Principal Investigator. 6. 18 years of age or older 7. Eastern Cooperative Oncology Group (ECOG) performance status score of ≤ 3 (APPENDIX 5) 8. No required wash-out period for prior therapies 9. HIV+ participants must be on stable antiretroviral treatment for 12 weeks before the first day of cycle 1 (C1D1), with CD4 count \>200 within the 7 days before C1D1. 10. Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: 1. Concurrent use of other systemic anticancer agents or treatments (including steroids unless adrenal insufficiency has been diagnosed) for mycosis fungoides or Sezary syndrome 2. Grade 2 or greater neuropathy 3. Severe renal impairment (creatinine clearance \[CrCL\] \