Inclusion Criteria \_ALS-patients:
* Age ≥18 years
* Able to provide written informed consent prior to study participation
* Body weight of ≥ 50 kg and a body mass index (BMI) between 19-30 kg/m2
* Vital signs measured after three minutes resting in the supine position must be within the following ranges:
* oral body temperature: 35.0-37.5 °C
* systolic blood pressure: 90-140 mm Hg
* diastolic blood pressure: 50-90 mm Hg
* pulse rate: 40-90 bpm
* Clinically probable, probable laboratory supported, or definite ALS-diagnosis according to the revised version of the El Escorial World Federation of Neurology criteria (EEC) (46)
* Disease duration ≤ 18 months since date of diagnosis
* Slow vital capacity (sVC) ≥ 80 % of normal (best of three measurements)
* Pre-study ALSFRS-R progression between disease onset and screening of -0.4 points/month or worse (calculated by ALSFRS-R score decline from 48 divided by months since symptom onset until screening)
* Patient has to be on a stable dose of disease modifying treatments (Edaravone 60 mg i.v.
on ten days/month, Riluzole 100 mg/day)
nclusion Criteria \_Healthy controls
* Age ≥ 18 years
* Able to provide written informed consent prior to study participation
* Body weight of ≥ 50 kg and a body mass index (BMI) between 19-30 kg/m2
* Vital signs measured after 3 minutes resting in the supine position must be within the following ranges:
* oral body temperature: 35.0-37.5 °C
* systolic blood pressure: 90-140 mm Hg
* diastolic blood pressure: 50-90 mm Hg
* pulse rate: 40-90 bpm
Exclusion Criteria\_ALS-patients
* Previous participation in another clinical study involving trial medication within the preceding 12 weeks prior to \[18F\]RoSMA-18-d6 administration
* Tracheostomy or continuous assisted ventilation of any type, or any other significant pulmonary disorder not attributed to ALS
* Structural brain or spinal cord abnormalities on MRI (e.g. evidence of stroke, infarct, or other space-occupying lesion or structural abnormality in brain and/or spinal cord.)
* Significant illness within two weeks prior to dosing
* History of clinically significant drug allergy; history of atopic allergy (asthma, urticaria, eczematous dermatitis). A known hypersensitivity to the study drug or drugs similar to the study drug
* History of allergic reaction to drugs or anaphylactic shock.
* History of myocardial infarction or history of treated cancer\[18F\]RoSMA-18-d6 in ALS brain and spinal cord\_ Version 1.1\_29.11.2022 Page 45 of 98
* Current clinically significant systemic illness or symptoms (e.g., respiratory or cardiovascular disease) that may deteriorate or affect the patient's safety or ability to cooperate during the study.
* Gastrostomy
* Any medical condition known to have an association with motor neuron dysfunction or involving neuromuscular weakness or another neurodegenerative disease, e.g. Parkinson's Disease (PD) or Alzheimer's disease (AD), which might confound or obscure the diagnosis of ALS
* Major internal disorders (e.g. arterial hypertension, diabetes, evidence suggestive of liver or renal disease (bilirubin \>1.6 mg/dL, creatinine \> 150 μM).
* Presence of any concomitant life-threatening disease or impairment likely to interfere with functional assessment
* Donation or loss of 400 mL or more of blood within eight weeks prior to dosing.
* Clinically relevant abnormalities on blood screening (see 4.3.1)
* Use of any prescription drug with central action or over-the-counter (OTC) medication within two weeks prior to dosing, except ALS-medication and Paracetamol which are acceptable.
* Use of tobacco products in the previous three months
* History of drug (e.g. Cannabis) or alcohol abuse within 12 months prior to dosing
* Pregnancy or breast feeding
Exclusion criteria\_healthy volunteers:
* Significant neurological or psychiatric disease
* Significant illness within two weeks prior to dosing
* History of clinically significant drug allergy; history of atopic allergy (asthma, urticaria, eczematous dermatitis). A known hypersensitivity to the study drug or drugs similar to the study drug.
* History of myocardial infarction or history of treated cancer
* Current clinically significant systemic illness or symptoms (e.g., respiratory or cardiovascular disease) that may deteriorate or affect the patient's safety or ability to cooperate during the study.
* Major internal disorders (e.g. arterial hypertension, diabetes, evidence of suggestive liver or renal disease (bilirubin \>1.6 mg/dL, creatinine \> 150 μM).
* Other clinically significant abnormality on physical, neurological, or laboratory examination that, in the opinion of the investigator precludes the patient from the study.
* Clinically significant abnormality on electrocardiogram (ECG) that, in the opinion of the investigator, precludes the patient from the study.
* A past medical history of clinically significant ECG abnormalities or a family history of a prolonged QT-interval syndrome.
* Structural brain or spinal cord abnormalities on MRI (e.g., evidence of stroke, infarct, or other space-occupying lesion or structural abnormality in brain and/or spinal cord). History of allergic disease or anaphylactic shock.
* Presence of any concomitant life-threatening disease or impairment likely to interfere with functional assessment
* Use of any prescription drug or over-the-counter (OTC) medication within two weeks prior to dosing. Paracetamol is acceptable.
* Use of tobacco products in the previous three months.
* History of drug (e.g. Cannabis) or alcohol abuse within 12 months prior to dosing.
* Participation in any clinical investigation within four weeks prior to dosing or any ever participation in a research study with an amyloid lowering objective.
* Donation or loss of 400 mL or more of blood within eight weeks prior to dosing.
* Clinically relevant abnormalities on blood screening (see 4.3.1)
* Significant radiation exposure, especially in the last quarter (either X-ray or nuclear medicine studies). Any earlier nuclear medicine studies.
* Pregnancy or breast feeding
