Satya Bose, Ph.D. Director of Radiation Safety & Head of Medical Physics

Transcription

Satya Bose, Ph.D. Director of Radiation Safety & Head of Medical Physics
Radiation Oncology Department
Howard University
Washington, DC
Satya Bose, Ph.D.
Director of Radiation Safety &
Head of Medical Physics
FDA Public Meeting June 9-10, 2010
Open Session 3: Quality Assurance
 Radiotherapy is a complex process.
 It involves understanding the principles:
 Medical physics
 Radiobiology
 Radiation safety
 Dosimetry
 Radiation treatment planning
 Interaction of
radiation with other modalities
 Goal is to ensure that each patient treated receives the best possible
long-term tumor control
Quality Assurance and Existing Protocols –
Are They Sufficient ?
 Goal is to deliver prescribed radiation dose with less than 5% overall uncertainty
 This requires to set tolerance limits for the planning and delivery system to make sure the
overall uncertainty is within the acceptable limits
 Complexity of Radiation treatments are increasing every year with the new
technology
 Computers are a vital part of the treatment process and requires serious attention to
Avoid ERRORS
 Each step in the integrated treatment process needs quality control (QC) and QA to
prevent errors and to give high confidence that patients will receive the prescribed
treatment correctly
 Goal is to link QA activities with Radiation Therapy to deliver dose precisely to the
target in order to achieve cure or palliation.
Quality Assurance and Existing Protocols –
Are They Sufficient ?
Overall QA procedures include, but not limited to the
followings:
Treatment Machine – hardware & software
Beam data commissioning
Treatment Planning software
Treatment plans
Treatment delivery Systems
Pre- and Post Treatment Image Acquisition to
verify Treatment Port
Quality Assurance and Existing Protocols –
Are They Sufficient ?
 Patient-specific QA is only a total system check. It does not tell
us anything about the accuracy with which the patient receives
treatments
 Accuracy is strongly dependent on the accuracy of:
 patient
positioning
 internal
 and
organ motion
the presence of heterogeneities
 Small movements in the target and normal tissues may lower
doses to the target and higher doses to the normal tissues
Existing Protocols – Are They Sufficient
Enough to Prevent Misadministration?
 Different QA protocols have set limits to measure the
performance of RT equipments.
 These tolerance limits are set strict, but can be achieved.
 Guidelines for these limits are provided in various
documents by AAPM Task Groups
 There are about 200 reports for different treatment modalities
recommended by AAPM.
 Each of these reports has its own QA procedures and
tolerance limits.
 External Peer Review may improve patient safety and quality
care
 Both regulatory authorities and professional societies should
work together to find out clinical needs for QA programs
Examples of Existing Protocols
 TG-40: Comprehensive QA for Radiation Oncology,
updated & superseded in report 142
 TG-41: Remote Afterloading Technology
 TG: 43: Dosimetry of Intestinal Brachytherapy sources,
updated (AAPM Report #84)
 TG-51: Protocol for clinical dosimetry of high energy
photons & electron beams
 TG-53: QA for clinical radiotherapy treatment planning
 TG-56: Code of practice for brachytherapy physics
 TG:59: High Dose Rate brachytherapy Treatment Delivery
Examples of Existing Protocols
Guidance document on delivery, treatment planning,
and clinical implementation of IMRT: Report of the
IMRT subcommittee of the AAPM radiation therapy
committee (Gary A. Ezzell)
TG64: Permanent prostate seed implant brachytherapy
TG-66: QA on CT -Do not know how many centers are
using?
TG-75: The management of imaging dose during imageguided radiotherapy.
Vendors specific procedures need to addressed
precisely
Existing Protocols-Are They Sufficient?
Are these protocols sufficient to protect us from
making mistakes?
What are the major causes of “Under Dose”, & “Over
Dose” in Radiotherapy Treatments?
To Err is Human:
Is this Error related to the device, the human being or the
method used?
 It is imperative to find the source of the problem

From 1976-2007, > 1700 patients received erroneous
treatments of which about 2% died due to radiation
overdose toxicity.
Existing Protocols-Are They Sufficient?
 About 98% of these incidents have occurred in the
planning stage during introduction of new equipments and
software
 About 7% due to the planning stage
 39% during transfer of information
 19% during treatment delivery
 Remaining 35% occurred in the categories of prescription,
simulation, patient positioning, mis-communications etc.
_________________________________________________
Reference: Quality Assurance of Radiotherapy in Cancer
Treatment: Towards Improvement of patient safety and
quality of care, Jpn J Clin Oncol 2008:38(11)723-729
Corrective Measures for Quality
Assurance
Independent check of a physicist’s work should be
performed
Formal procedures for calibrating the treatment unit
on a regular schedule should exist and be followed.
A department should provide sufficient staff to handle
the workload.
Records must accurately document the performance of
accepted QA procedures.
Develop procedures that clearly indicate the software
commissioned for clinical use, and software that has
been removed from clinical service.
Mandatory QA Check List
Follow Policies and Procedures that describe all processes
Create a QA checklist based on Policies and Procedures to
follow each step of the treatment planning and delivery
procedures
The checklist must be followed by the dosimetrist,
therapists, physicists & other staff member of the
department covering all points from A to Z
Follow checklist on each case through the entire course of
treatment to prevent errors in order to ensure patient safety
Mandatory Time Out
Need a checklist for the Front Desk
Need a checklist for the Sim-tech
Need a checklist for the Dosimetrists – you need a
mandatory Time Out
Need a checklist for the Physicists – give yourself a Time
Out - don’t rush
Need a checklist for the Physicians – don’t sign plans give
yourself a Time Out
Need a checklist for the Therapists – don’t treat until you
give yourself a Time Out
Comments on NY Times News Report
 Open Jaw and Open MLC & Open treatment patient anatomy
 Plan done and approved by the physician without checking
 Patient was then treated, but the computer crashed again
 No IMRT QA was done & did not follow IMRT QA protocol
 Therapists did not monitor computer screen
 Physicians failed to verify the treatment port
 Secondary dosimetry system was not used
 Use of secondary dosimetry system (TLD’s, diodes etc.) during the
first treatment could have saved the patient
 Bad practice to implement IMRT program without an approved
protocol in place
Frequently Asked Questions…
•
•
•
•
•
•
•
•
Are your treatment planning systems reliable?
Are your equipment delivery systems reliable?
Is it OKAY to assume it is safe?
Are you missing a step?
Are you nervous?
Are you confident?
Do you TRUST yourself?
Can you smile at the end of the day (are you satisfied with your
work)?
Take two steps backwards before you take one step forward
(CHECK YOUR WORK)
Thank You!