Best Practices with Radiochromic Film: Question Set

1. Which of thefollowing is not a charge of AAPM TG-235, “Radiochromic Film Dosimetry: An Update to TG-55”?

(a) / To review the literature on RCF dosimetry in radiation therapy since TG-55
(b) / To assess the densitometers/scanners used for digitizing RCF since TG-55
(c) / To outline the procedures for accurate dosimetry and to evaluate measurement uncertainties
(d) / To highlight the advantages of RCF as compared to other types of dosimeters
(e) / To provide guidelines on RCF dosimetry for clinicalradiotherapy applications

Answer: d-To highlight the advantages of RCF as compared to other types of dosimeters

Ref: AAPM Task Group #235, “Radiochromic Film Dosimetry: An Update to TG-55”,

2. Which of the following statement on radiochromic film model is true?

(a) / RTQA2 is for IMRT dose QA
(b) / EBT2/3 is more sensitive to light than EBT film
(c) / XR-RV3 has the highest low energy response
(d) / XRQA2 has the highest low energy response
(e) / EBT-XD film covers a dose range up to 10Gy

Answer: d-XRQA2 has the highest low energy response

Ref: C. G. Soares, S. Trichter and S. Devic, “Radiochromic Film Dosimetry,” In: D. W. O. Rogers and J. Cygler, Eds., Clinical Dosimetry for Radiotherapy, Medical Physics Publishing, Madison, 2009, pp. 759-813.

3. Which is not a proper way to handle radiochromic film?

(a) Store film in an area of controlled humidity, dark environment

(b) Handle film with care, avoiding dust, fingerprints, or crimping

(d) Identify film orientation and alignment and filmsconsistently

(e) Use the same film lot for both calibration and dose measurement

Answer: c-Keep a consistent temp.~25-27oC for storage, irradiation, and scanning

Best Practices with Radiochromic Film: Question Set

4. Which is not true about multichannel film dosimetry as compared to single-channel dosimetry?

(a) / Better non-uniformity correction of radiochromic film
(b) / Rational functions for curve fitting of calibration data (dose vs. response)
(c) / Often use 3rd-4th order of polynomial fitting for calibration data
(d) / Correction for a variety of anomalies, artifacts, and other disturbances
(e) / Must use a specialized film digitizer/scanner with 48-bit RGB channels

Answer: c-Often use 3rd-4th order of polynomial fitting for calibration data

Ref: A. Micke, D. F. Lewis and X. Yu, “Multichannel Film Dosimetry with Nonuniformity Correction,” Med Phys, Vol. 38, No. 5, 2011, pp. 2523-2534.

5. Whichsource of doseerrorscan the “One-scan protocol” not eliminate?

(a) / Inter-scan variation
(b) / Effects of temperature and humidity conditions
(c) / Film lot difference
(d) / Different scanners and types
(e) / Post-exposure density growth

Answer: c-Film lot difference

Ref: D. Lewis, A. Micke, X. Yu and M. F. Chan, “An Efficient Protocol for Radiochromic Film Dosimetry Combining Calibration and Measurement in a Single Scan,” Med Phys, Vol. 39, No. 10, 2012, pp. 6339-6350.