To estimate the dose equivalent (H_1cm) of a person who may come into close contact with patients exposed to ²⁰¹T1, dose rates around 15 adult patients (rest group: 8, exercise group: 7) have been measured with ionization survey meters. Measurements were carried out at 30min, 24h, 72h, 144h (or 120h) and 216h after the administration of ²⁰¹T1Cl. Survey meters were set up at the height of the first cervical vertebrae (I), xiphoid process (II) and anterior superior iliac spines (III) with the patient in a standing posture, and at distances of 0.05, 0.5, 1.0 and 1.5m from the patient. The maximum H_1cm rate of 18.37μSv/h per 74MBq was recorded at level II in the anterior projection. Doses in the posterior projection were similar to those at the anterior projection, however, in the right- and left-lateral projections the doses were lower than the anterior dose. The difference in doses between the rest and exercise groups was slight. The calculated effective half-life was 63.0h. H_1cm^S were 891, 196, 77 and 42μSv/w per 74MBq at distances of 0.05, 0.5, 1.0 and 1.5m, respectively. These H_1cm^S correspond to 84% of the total H_1cm^S (μSv/∞h). The family of a patient given ²⁰¹T1 was one-third of the total H_1cm at 0.05m, the dose did not exceed the dose limit described in recommendations-1990 of ICRP. However, it was a substantial dose for them. Staff doses in general wards and in special wards (ICU or CCU) were one-fourth of a total H_1cm at 0.5m, these doses were the result of contact with 17 ²⁰¹T1 patients and 257 ²⁰¹T1 patients for one year. The dose of patient in the same room as patients given ²⁰¹T1 were 42μSv/w at 1.5m; this dose did not exceed his dose limit of 100μSv/w. These results do not suggest that radiation protection is necessary when exposed to a patient given ²⁰¹T1, but in the case of close contact with many ²⁰¹T1 patients, it would be necessary when the radiation dose exceeds the limit.