Accuracy

«Accuracy describes the difference between the measurement and the actual value of the part that is measured. It includes:

• Bias: a measure of the difference between the true value and the observed value of a part. If the “true” value is unknown, it can be calculated by averaging several measurements with the most accurate measuring equipment available.
• Linearity: a measure of how the size of the part affects the bias of a measurement system. It is the difference in the observed bias values through the expected range of measurement [1].»

  

  [1]

It is «analogous to uncertainty relative to a reference, is in its simplest terms the difference between measured and “true” values [2].»

Bibliographic references:

[1] Reliawiki. 2017. Measurement System Analysis. [online] Available at: <https://reliawiki.org/index.php/Measurement_System_Analysis> [Accessed 20 February 2022].

[2] Apogeeinstruments.com. 2022. Uniformity, Repeatability, Stability, and Accuracy. [online] Available at: <https://www.apogeeinstruments.com/uniformity-repeatability-stability-and-accuracy/> [Accessed 20 February 2022].

Actuarial (versus actual)

«Its use is often extended (...) to include the Kaplan-Meier (KM) method, (...). Actual is a new term (...) to refer to a technique with several designations in the statistical literature, including cumulative incidence and crude, unadjusted, absolute, or observable probability [1].»

«Actuarial analysis, (...), is used to describe and compare survival probabilities by allowing for partial survival times (censoring). (...) The actuarial event-free (survival) curve for a nonfatal event, such as structural valve deterioration (SVD) of porcine valves, estimates the event-free probability for a population in which death has been eliminated. This overestimates the percentage of valves that will actually fail, because many patients die before the valve fails [2].»

«Unlike cumulative incidence [actual estimates], the KM attempts to predict what the latent failure probability would be if death were eliminated. To do this, the KM method assumes that the risk of dying and the risk of failure are independent. But this assumption is not true for many cardiac applications in which the risks of failure and death are negatively correlated (ie, patients with a higher risk of dying have a lower risk of failure, and patients with a lower risk of death have a higher risk of failure, which is a condition called informative censoring) [3].»

«When used for nonfatal events such as SVD, actual analysis estimates the percentage of patients who will have SVD (or the probability that an individual patient will experience SVD). The KM (actuarial) method attempts to estimate the percentage of SVD that would occur if patients never died. Also, KM depends on the assumption that death and SVD are independent, which they are probably not [1].»

Bibliographic references:

[1] Grunkemeier GL, Wu Y. Actual versus actuarial event-free percentages. Ann Thorac Surg. 2001 Sep;72(3):677-8. Available at: https://doi.org/10.1016/s0003-4975(01)03059-4.

[2] Grunkemeier GL, Jamieson WR, Miller DC, Starr A. Actuarial versus actual risk of porcine structural valve deterioration. J Thorac Cardiovasc Surg. 1994 Oct;108(4):709-18. PMID: 7934107. Available at: https://doi.org/10.1016/S0022-5223(94)70298-5.

[3] Grunkemeier GL, Jin R, Eijkemans MJ, Takkenberg JJ. Actual and actuarial probabilities of competing risks: apples and lemons. Ann Thorac Surg. 2007 May;83(5):1586-92. Available at: https://doi.org/10.1016/j.athoracsur.2006.11.044.

Active Breathing Coordinator (ABC) device for lung cancer or abdominal tumors

Accelerated hyperfractionation

It is the combined rationales of accelerated fractionation and hyperfractionation: «increase in fraction number, reduction in fraction size and treatment time, compared with conventional.»

Bibliographic reference: Thames HD Jr, Peters LJ, Withers HR, Fletcher GH. Accelerated fractionation vs hyperfractionation: rationales for several treatments per day. Int J Radiat Oncol Biol Phys. 1983 Feb;9(2):127-38. Available at: https://doi.org/10.1016/0360-3016(83)90089-5.

Accelerated fractionation

«Overall time shorter than conventional, achieved by giving 2 or 3 doses daily; total dose and fraction size similar to conventional.»

Bibliographic reference: Thames HD Jr, Peters LJ, Withers HR, Fletcher GH. Accelerated fractionation vs hyperfractionation: rationales for several treatments per day. Int J Radiat Oncol Biol Phys. 1983 Feb;9(2):127-38. Available at: https://doi.org/10.1016/0360-3016(83)90089-5.

AJCC

American Joint Committee on Cancer

Anorectal anatomy

«Note the anal crypts and glands; 90 percent of anorectal fistulas originate in a cryptoglandular abscess. Also note the relationship of the crypts and glands to the internal and external sphincters.»

Source: UpToDate [Internet]. Uptodate.com. 2019 [cited 2019 May 26]. Available from: https://www.uptodate.com/contents/image?imageKey=SURG%2F72874&topicKey=SURG%2F17127&search=rectum&source=outline_link&selectedTitle=1~150.

«The anal canal is 2.5 to 3.5 cm long and begins superiorly where the rectal ampulla is narrowed by the puborectalis sling (the levator ani muscle, which is palpable as the anorectal ring). It ends at the intersphincteric groove. Externally, the anal canal is surrounded by the internal and external anal sphincter muscles.

The superior half of the anal canal contains a series of longitudinal ridges called the anal columns (of Morgagni), which extend from the anorectal junction superiorly to the anal valves inferiorly. The anal valves form an irregular line called the dentate (or pectinate) line (colored purple in the diagram), which is an important anatomical landmark. The portions of the anal canal superior and inferior to it have different origins of arterial supply, nerve innervation, venous/lymphatic drainage, and epithelial lining.

The anal canal is internally lined with mucous membrane above the dentate line and anoderm below it. The upper portion of the anoderm (anal verge) consists of smooth, hairless skin; the lower portion of the anoderm (perianal skin) contains pigmented skin containing hair follicles and glands.»

Source: UpToDate [Internet]. Uptodate.com. 2019 [cited 2019 May 26]. Available from: https://www.uptodate.com/contents/image?imageKey=ONC%2F62539&topicKey=ONC%2F106743&search=rectal%20cancer&source=outline_link&selectedTitle=1~150.

Acute side effects of radiotherapy

Toxicity typically occurring within 3 months of treatment.

Bibliographic reference: Peach MS, et al. Systematic Review of the Relationship between Acute and Late Gastrointestinal Toxicity after Radiotherapy for Prostate Cancer. Prostate Cancer. 2015;2015:624736. Available at: https://doi.org/10.1155/2015/624736.

Abscopal effect

AFU

Association Française d’Urologie, the French Association of Urology.

Adjuvant therapy

It is an «additional cancer treatment given after the primary treatment to lower the risk that (...) cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or biological therapy.»

Bibliographic reference: National Cancer Institute. (n.d.). NCI Dictionary of Cancer Terms. [online] Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms?CdrID=45587 [Accessed 10 May 2017].

α/β, alpha/beta ratio

The ratio of “intrinsic radiosensitivity” to “repair capability” of a specified tissue (in units of Gy). This ratio is large (>8 Gy) for rapidly proliferating tissues and most tumors. It is small (<6 Gy) for slowly proliferating tissues, including late normal-tissue complications. This difference is vital for the success of radiotherapy. When beta (β) is large, both mis-repair and good-repair are high. It is the mis-repair that causes the cell survival curve to bend downward [1]. It is the "dose for which the number of acutely responding cell deaths is equal to the number of late-responding cell deaths (the dose for which the linear and quadratic components of cell death are equal). (...) The α/β ratio may differ among tumor types" [2]. It is the fractionation factor [13]. For skin tumors, the α/β for 90% control rate is 13.8 Gy [3].

	List of α/β (Gy)
Heart	3 [3]
Spinal cord (radiation myelopathy)	0,87 [12], 2 [4,5]
Lung	3 [4], 4 (fibrosis), 5 (pneumonitis) [5], 2.7-4 (late reactions) [6]
Liver (fibrosis)	1 [4,5]
Kidney (nephropathy)	2 [5], 3 [4], 2-2.4 (late reactions) [6]
Parotid gland	2 [4]
Salivary glands (permantent xerostomia)	3 [5]
Lachrymal system (dry eye, ulceration)	3 [5]
Nervous system	3 [4]
Central nervous system (brain, spinal cord) (late reactions)	1.8-2.2 [6]
Eye lens (cataract)	1-2 [5]
Optic nerve (neuropathy)	2 [5]
Chiasma opticum (loss of vision)	2 [5]
Testicle	1 [4]
Testis (early reactions)	12-13 [6]
Ovary	1 [4]
Eye	1 [4]
Bone	3 [4]
Bone marrow	10 (transient hypoplasia), 5 (lethal aplasia [1 year]) [5]
Cartilage	1 [4], 6 [5]
Larynx (chronic oedema, necrosis)	2-4 [5]
Rectum (chronic inflammation, ulcer)	5 [4,5], 2.5-5 (late reactions) [6]
Urinary bladder	2 [4], 10 (acute cystitis), 5-10 (shrinkage, ulceration) [5], 3-7 (late reactions) [6]
Skin (acute erythema, dry radiodermatitis)	8.8 (erytema) (confidence interval: 6.9; 11.6) [14], 9-10 [5], 9-12 (early reactions) [6], 11,2 (desquamation) (confidence interval: 8.5; 17.6) [14], 12.3 (erytema) (confidence interval: 1.8; 22.8) [15]
Hair follicles (hair loss)	7 [5]
Mucosa (early reactions)	9-10 [6]
Oral mucosa (acute ulcerative mucositis)	10 [5]
Stomach (ulcer)	4 [5]
Small intestine (acute malabsorption)	8 [5]
Jejunum (early rections)	6-10 [6]
Small intestine (ulcer/obstruction)	4 [5]
Colon (early reactions)	9-11 [6]
Breast, adult (fibrosis/atrophy)	2-3 [5]

Human tumors	List of α/β (Gy)
Malign melanoma	0.57 [7], 1.5 [2]
Prostate adenocarcinoma	1.2 [8], 1.49 [9], 1.5-3.5 [2,10]
Bladder cancer (transitional cell carcinoma)	13 (for external beam radiotherapy [EBRT]) and 24 (for EBRT and brachytherapy) [16]
Rhabdomyosarcoma	2.8 [11]
Skin	13.8 [3]
Vocal cord	9.9 (Harrison et al., 1988, cited in [6])
Oropharynx	13-19 (Rezvani et al., 1993, cited in [6])
Larynx	25-35 (Maciejewski et al., 1988, cited in [6]), 50-infinity (Chappell et al., 1995, and Roberts et al., 1998, cited in [6])

Bibliographic references:
[1] Fowler, J. (2006). Part I: Basic Concepts in Treatment Planning, 1. Practical Time-Dose Evaluations, or How to Stop Worrying and Learn to Love Linear Quadratics. In: S. Levitt, J. Purdy, C. Perez and S. Vijayakumar, ed., Technical Basis of Radiation Therapy, Practical Clinical Applications, 4th ed. Springer-Verlag Berlin Heidelberg, pp.3-31.
[2] Beyzadeoglu, M., Ozyigit, G. and Ebnuli, C. ed., (2010). 2.6.2. Linear-Quadratic Model (LQ Model). In: Basic Radiation Oncology, 1st ed. Berlin: Springer Berlin Heidelberg, p.104.
[3] Maia MAC, Oliveira SC. Radioterapia nos tumores de pele. In: Âmbito Editores Ltda, 3.ª ed. Manual de condutas diagnósticas e terapêuticas em oncologia [Portuguese]. São Paulo, Brazil: Kowalski LP, Guimarães GC, Salvajoli JV, Feher O, Antoneli CBG (eds.); 2006; 327-330.
[4] Sfjro.fr. (2010). eLQ - Radiation Therapy Equivalent Dose Calculator. [online] Available at: http://www.sfjro.fr/ilq/en/biblio.html [Accessed 25 Jul. 2016].
[5] Dörr, W. (2009). 13 - Pathogenesis of normal-tissue side-effects. In: M. Joiner and A. van der Kogel, ed., Basic Clinical Radiobiology, 4th ed. London, United Kingdom: Hodder Arnold, an Hachette UK Company, pp.179-181.
[6] Fowler JF. The radiobiology of prostate cancer including new aspects of fractionated radiotherapy. Acta Oncol. 2005;44(3):265-76. Available at: http://dx.doi.org/10.1080/02841860410002824.
[7] Bentzen SM, Overgaard J, Thames HD, Overgaard M, Vejby Hansen P, von der Maase H, et al. Clinical radiobiology of malignant melanoma. Radiother Oncol. 1989 Nov;16(3):168-82. Available at: http://dx.doi.org/10.1016/0167-8140(89)90017-0.
[8] Brenner DJ, Martinez AA, Edmundson GK, Mitchell C, Thames HD, Armour EP. Direct evidence that prostate tumors show high sensitivity to fractionation (low alpha/beta ratio) comparable to late-responding normal tissue. Int J Radiat Oncol Biol Phys. 2002 Jan 1;52(1):6-13. Available at: http://dx.doi.org/10.1016/s0360-3016(01)02664-5.
[9] Fowler JF. Biological factors influencing optimum fractionation in radiation therapy. Acta Oncol. 2001;40(6):712-7. Available at: http://dx.doi.org/10.1080/02841860152619124.
[10] Brenner DJ, Hall EJ. Fractionation and protraction for radiotherapy of prostate carcinoma. Int J Radiat Oncol Biol Phys. 1999 Mar 15;43(5):1095-101. Available at: http://dx.doi.org/10.1016/S0360-3016(98)00438-6.
[11] Timmerman RD, Mendonca M. In regard to Donaldson et al: results from the IRS-IV randomized trial of hyperfractionated radiotherapy in children with rhabdomyosarcoma-a report from the IRSG. IJROBP 2001;51:718-728. Int J Radiat Oncol Biol Phys. 2002 Dec 1;54(5):1579-80; author reply 1580. Available at: http://dx.doi.org/10.1016/S0360-3016(02)03015-8.
[12] Schultheiss TE. The radiation dose-response of the human spinal cord. Int J Radiat Oncol Biol Phys. 2008 Aug 1;71(5):1455-9. Available at: http://dx.doi.org/10.1016/j.ijrobp.2007.11.075.
[13] Dale RG, Hendry JH, Jones B, et al. Practical methods for compensating for missed treatment days in radiotherapy, with particular reference to head and neck schedules. Clin Oncol (R Coll Radiol). 2002 Oct;14(5):382-93. Available at: http://dx.doi.org/10.1053/clon.2002.0111.
[14] Turesson I, Thames HD. Repair capacity and kinetics of human skin during fractionated radiotherapy: erytema, dequamation, and telangiectasia after 3 and 5 year's follow-up. Radiother Oncol. 1989 Jun;15(2):169-88. Available at: https://doi.org/10.1016/0167-8140(89)90131-x.
[15] Bentzen SM, Christensen JJ, Overgaard J, Overgaard M. Some methodological problems in estimating radiobiological parameters from clinical data. Alpha/beta ratios and electron RBE for cutaneous reactions in patients treated with postmastectomy radiotherapy. Acta Oncol. 1988;27(2):105-16. Available at: https://doi.org/10.1016/0167-8140(89)90131-x.
[16] Pos FJ, Hart G, Schneider C, Sminia P. Radical radiotherapy for invasive bladder cancer: What dose and fractionation schedule to choose? Int J Radiat Oncol Biol Phys. 2006 Mar 15;64(4):1168-73. Available at: https://doi.org/10.1016/j.ijrobp.2005.09.023.

α, alpha

Intrinsic radiosensitivity. Loge of the number of cells sterilized non-repairably per gray of dose of ionizing radiation.
Bibliographic reference: Fowler, J. (2006). Part I: Basic Concepts in Treatment Planning, 1. Practical Time-Dose Evaluations, or How to Stop Worrying and Learn to Love Linear Quadratics. In: S. Levitt, J. Purdy, C. Perez and S. Vijayakumar, ed., Technical Basis of Radiation Therapy, Practical Clinical Applications, 4th ed. Springer-Verlag Berlin Heidelberg, pp.3-31.

ASTRO

American Society for Radiation Oncology.

Bibliographic reference - Astro.org. (2016). ASTRO - American Society for Radiation Oncology (ASTRO). [online] Available at: https://www.astro.org/home/ [Accessed 1 May 2016].