Establishment and Evaluation of Standardized Clinical, Biological and Imaging Parameters to Assess the Response of LDRT in Heel Spur With Plantar Fasciitis

Inclusion Criteria: * Age \> 39 years * Typical clinical picture of plantar fasciitis for at least 3 months without associated trauma, other musculoskeletal co-morbidities or degenerative joint disease * Patients with first-time application of LDRT to the affected joint * Willingness to cooperate and accessibility of patients, especially geographical proximity, for treatment and follow-up * Patients for whom LDRT is indicated independently of the study * Karnofsky Index \>70% Exclusion Criteria: * Achillodynia ("dorsal" calcaneal spur) * Previous trauma to the foot (fracture, tendon rupture) * Musculoskeletal comorbidities of the foot * Acute infections/open wounds in the area of the tendon to be examined or other relevant damage to the tendon to be examined * Local steroid injections into the tendon prior to the study * Rheumatic or vascular diseases, lymphedema * Patients with tumors * Individuals of childbearing potential who do not use adequate contraceptive measures consistently during therapy * Persistent drug, medication or alcohol abuse * Patients who have already undergone radiotherapy for the treatment of cancer * Patients with an increased risk of an MRI examination, including the presence of metal implants, pacemakers or claustrophobia