10 CFR § 35.2642 - Records of periodic spot-checks for teletherapy units.

---
identifier: "/us/cfr/t10/s35.2642"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "10 CFR § 35.2642 - Records of periodic spot-checks for teletherapy units."
title_number: 10
title_name: "Energy"
section_number: "35.2642"
section_name: "Records of periodic spot-checks for teletherapy units."
chapter_name: "NUCLEAR REGULATORY COMMISSION"
part_number: "35"
part_name: "MEDICAL USE OF BYPRODUCT MATERIAL"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Atomic Energy Act of 1954, secs. 81, 161, 181, 182, 183, 223, 234, 274 (42 U.S.C. 2111, 2201, 2231, 2232, 2233, 2273, 2282, 2021); Energy Reorganization Act of 1974, secs. 201, 206 (42 U.S.C. 5841, 5846); 44 U.S.C. 3504 note."
regulatory_source: "67 FR 20370, Apr. 24, 2002, unless otherwise noted."
cfr_part: "35"
---


# 35.2642 Records of periodic spot-checks for teletherapy units.

(a) A licensee shall retain a record of each periodic spot-check for teletherapy units required by § 35.642 for 3 years.

(b) The record must include—

(1) The date of the spot-check;

(2) The manufacturer's name, model number, and serial number of the teletherapy unit, source and instrument used to measure the output of the teletherapy unit;

(3) An assessment of timer linearity and constancy;

(4) The calculated on-off error;

(5) A determination of the coincidence of the radiation field and the field indicated by the light beam localizing device;

(6) The determined accuracy of each distance measuring and localization device;

(7) The difference between the anticipated output and the measured output;

(8) Notations indicating the operability of each entrance door electrical interlock, each electrical or mechanical stop, each source exposure indicator light, and the viewing and intercom system and doors; and

(9) The name of the individual who performed the periodic spot-check and the signature of the authorized medical physicist who reviewed the record of the spot-check.

(c) A licensee shall retain a copy of the procedures required by § 35.642(b) until the licensee no longer possesses the teletherapy unit.