---
kind: "section"
citation: "10 C.F.R. § 35.633"
title: "10"
number: "35.633"
heading: "Full calibration measurements on remote afterloader units."
url: "https://uscodex.org/cfr/10/35.633"
---

# §35.633. Full calibration measurements on remote afterloader units.

- (a) A licensee authorized to use a remote afterloader unit for medical use shall perform full calibration measurements on each unit—
  - (1) Before the first medical use of the unit;
  - (2) **Before medical use under the following conditions—**
    - (i) Following replacement of the source or following reinstallation of the unit in a new location outside the facility; and
    - (ii) Following any repair of the unit that includes removal of the source or major repair of the components associated with the source exposure assembly; and
  - (3) At intervals not exceeding 1 quarter for high dose-rate, medium dose-rate, and pulsed dose-rate remote afterloader units with sources whose half-life exceeds 75 days; and
  - (4) **At intervals not exceeding 1 year for low dose-rate remote afterloader units.**
- (b) To satisfy the requirement of [paragraph (a)](#a) of this section, full calibration measurements must include, as applicable, determination of:
  - (1) The output within ±5 percent;
  - (2) Source positioning accuracy to within ±1 millimeter;
  - (3) Source retraction with backup battery upon power failure;
  - (4) Length of the source transfer tubes;
  - (5) Timer accuracy and linearity over the typical range of use;
  - (6) Length of the applicators; and
  - (7) **Function of the source transfer tubes, applicators, and transfer tube-applicator interfaces.**
- (c) A licensee shall use the dosimetry system described in [§ 35.630(a)](/cfr/10/35.630.md?p=a) to measure the output.
- (d) A licensee shall make full calibration measurements required by [paragraph (a)](#a) of this section in accordance with published protocols accepted by nationally recognized bodies.
- (e) In addition to the requirements for full calibrations for low dose-rate remote afterloader units in [paragraph (b)](#b) of this section, a licensee shall perform an autoradiograph of the source(s) to verify inventory and source(s) arrangement at intervals not exceeding 1 quarter.
- (f) For low dose-rate remote afterloader units, a licensee may use measurements provided by the source manufacturer that are made in accordance with [paragraphs (a) through (e)](#a..e) of this section.
- (g) A licensee shall mathematically correct the outputs determined in [paragraph (b)(1)](#b-1) of this section for physical decay at intervals consistent with 1 percent physical decay.
- (h) Full calibration measurements required by [paragraph (a)](#a) of this section and physical decay corrections required by [paragraph (g)](#g) of this section must be performed by the authorized medical physicist.
- (i) A licensee shall retain a record of each calibration in accordance with [§ 35.2632](/cfr/10/35.2632.md).

## Notes

### Authority

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.

### Source

Source: 67 FR 20370, Apr. 24, 2002, unless otherwise noted.