(-c-) If a device using a light source is used to satisfy
the requirements of item (-a-) or (-b-) of this subclause, the light
source shall provide illumination levels sufficient to permit visual
determination of the location of the tomographic plane or reference
plane under ambient light conditions of up to 500 lux.
(II) The CT x-ray system shall be designed such that
the CT conditions of operation to be used during a scan or a scan
sequence are indicated prior to the initiation of a scan or a scan
sequence. On equipment having all or some of these conditions of operation
at fixed values, this requirement may be met by permanent markings.
Indication of CT conditions shall be visible from any position from
which scan initiation is possible.
(III) The x-ray control and gantry shall provide visual
indication whenever x rays are produced and, if applicable, whether
the shutter is open or closed.
(IV) Means shall be provided to require operator initiation
of each individual scan or series of scans.
(V) All emergency buttons/switches shall be clearly
labeled as to their functions.
(VI) Termination of exposure shall be as follows.
(-a-) Means shall be provided to terminate the x-ray
exposure automatically by either de-energizing the x-ray source or
shuttering the x-ray beam in the event of equipment failure affecting
data collection. Such termination shall occur within an interval that
limits the total scan time to no more than 110% of its preset value
through the use of either a backup timer or devices that monitor equipment
function.
(-b-) A signal visible to the operator shall indicate
when the x-ray exposure has been terminated through the means required
by item (-a-) of this subclause.
(-c-) The operator shall be able to terminate the x-ray
exposure at any time during a scan or series of scans under CT x-ray
system control, of greater than 0.5 second duration. Termination of
the x-ray exposure shall necessitate resetting of the CT conditions
of operation prior to initiation of another scan.
(VII) CT x-ray systems containing a gantry manufactured
after September 3, 1985, shall meet the following requirements.
(-a-) The total error in the indicated location of
the tomographic plane or reference plane shall not exceed 5 mm.
(-b-) If the x-ray production period is less than 0.5
second, the indication of x-ray production shall be actuated for at
least 0.5 second. Indicators at or near the gantry shall be discernible
from any point external to the patient opening where insertion of
any part of the human body into the primary beam is possible.
(-c-) The deviation of indicated scan increment versus
actual increment shall not exceed ±1 mm with any mass from
0 to 100 kilograms (kg) resting on the support device. The patient
support device shall be incremented from a typical starting position
to the maximum incremented distance or 30 cm, whichever is less, and
then returned to the starting position. Measurement of actual versus
indicated scan increment can be taken anywhere along this travel.
(ii) Facility design requirements.
(I) Provision shall be made for two-way aural communication
between the patient and the operator at the control panel.
(II) Windows, mirrors, closed-circuit television, or
an equivalent shall be provided to permit continuous observation of
the patient during irradiation and shall be so located that the operator
can observe the patient from the console.
(-a-) Should the viewing system described in subclause
(II) of this clause fail or be inoperative, treatment shall not be
performed with the unit until the system is restored.
(-b-) In a facility that has a primary viewing system
by electronic means and an alternate viewing system, should both viewing
systems described in subclause (II) of this clause fail or be inoperative,
treatment shall not be performed with the unit until 1 of the systems
is restored.
(iii) Dose measurements of the radiation output of
the CT x-ray system.
(I) Dose measurements of the radiation output of the
CT x-ray system shall be performed by a licensed medical physicist
with a specialty in diagnostic radiological physics. If the CT system
is used for simulation purposes only, the following requirements do
not apply. If the unit is also used for diagnostic procedures, the
measurements shall be performed as follows:
(-a-) within 30 days after installation and thereafter,
at intervals not to exceed 14 months;
(-b-) when major maintenance that could affect radiation
output is performed; or
(-c-) when a major change in equipment operation (e.g.
introduction of a new software package) is accomplished.
(II) Measurements of the radiation output of a CT x-ray
system shall be performed with a calibrated dosimetry system. The
dosimetry system calibration shall be traceable to a national standard.
The calibration interval shall not exceed 24 months.
(III) Records of dose measurements specified in clause
(iii) of this subparagraph shall be maintained by the registrant in
accordance with subsection (l) of this section for inspection by the
agency.
(iv) A maintenance schedule shall be developed in accordance
with the manufacturer's United States Department of Health and Human
Services maintenance schedule. The schedule shall include, but need
not be limited to the following:
(I) dose measurements required by clause (iii)(I) of
this subparagraph; and
(II) acquisition of images obtained with phantoms using
the same processing mode and CT conditions of operation as are used
to perform dose measurements required by clause (iii)(I) of this subparagraph.
The registrant shall retain either of the following in accordance
with subsection (l) of this section for inspection by the agency:
(-a-) photographic copies of the images obtained from
the image display device; or
(-b-) images stored in digital form.
(i) Medical events (misadministrations).
(1) Medical events involving equipment operating at
energies below 1 MeV and electronic brachytherapy devices, shall be
reported when:
(A) the event involves the wrong individual, or wrong
treatment site;
(B) the treatment consists of 3 or fewer fractions
and the calculated total administered dose differs from the total
prescribed dose by more than 10% of the total prescribed dose; or
(C) the calculated total administered dose differs
from the total prescribed dose by more than 20% of the total prescribed
dose.
(2) Medical events involving equipment operating with
energies of 1 MeV and above shall be reported when:
(A) the event involves the wrong individual, wrong
type of radiation, wrong energy, or wrong treatment site;
(B) the treatment consists of 3 or fewer fractions
and the calculated total administered dose differs from the total
prescribed dose by more than 10% of the total prescribed dose;
(C) the calculated total administered dose differs
from the total prescribed dose by more than 20% of the total prescribed
dose; or
(D) the combination of external beam radiation therapy
and radioactive material therapy causes over-radiation of a patient
resulting in physical injury or death.
(j) Reports of medical events (misadministrations).
(1) For a medical event, a registrant shall do the
following:
(A) notify the agency by telephone no later than 24
hours after discovery of the event;
(B) notify the referring physician and also notify
the patient of the event no later than 24 hours after its discovery,
unless the referring physician personally informs the registrant either
that he or she will inform the patient or that, based on medical judgement,
telling the patient would be harmful. The registrant is not required
to notify the patient without first consulting the referring physician.
If the referring physician or patient cannot be reached within 24
hours, the registrant shall notify the patient as soon as possible
thereafter. The registrant may not delay any appropriate medical care
for the patient, including any necessary remedial care as a result
of the event, because of any delay in notification;
(C) submit a written report to the agency within 15
days after the discovery of the event. The report shall not include
the patient's name or other information that could lead to identification
of the patient. The written report shall include the following:
(i) registrant's name and certificate of registration
number;
(ii) prescribing physician's name;
(iii) a brief description of the event;
(iv) why the event occurred;
(v) the effect on the patient;
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